1995 SCVIR Meeting Abstracts

1995 SCVIR Meeting Abstracts The following are abstracts of scientific sessions papers to be presented at the 20th Annual Scientific Meeting of the Society of Cardiovascular and Interventional Radiology, March 25-30, 1995, Fort Lauderdale, Florida. Authors with an * following their name have informed the SCVIR that a potential conflict of interest exists.

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Sunday, March 26 Room 315 Scientific Session 1 Stents: New Prototypes MODERATOR:

Gordon K. McLean, MD, Pittsburgh,

PA

Development of a Vascular Stent Made from Autologous Porcine Vein H. Yoon, MD, PhD S.C. Goodwin, MD E.K. Nishimura, MD, Los Angeles, CA PURPOSE: Development of an endovascular biologic stent with compliance characteristics comparable to those of native vessels. MATERIALS AND METHODS: A new endovascular biologic stent has been made from autologous porcine vein. The veins undergo chymotryptic digestion to remove as many cellular elements as possible and leave a collagen-elastin tube. Subsequent crosslinking provides additional tensile strength. Antithrombotic agents, such as heparin, can be incorporated into the stent wall. The stents are dried onto a conventional balloon angioplasty catheter for deployment. The stents recover their resiliency after introduction into the vessel lumen. The stent eventually is incorporated into the vessel wall. RESULTS: Initial results with various deployment systems are described in an atherogenic swine model of iliac artery disease. The stent appears to incorporate rapidly into the native vessel wall. Different methods for the incorporation of bioactive substances are also presented. CONCLUSION: A biologic stent has the advantages of compliance matching, incorporation into the native vessel wall, and the ability to deliver various bioactive substances to the damaged endothelium.

New Mechanically Expandable Vascular Stent V.S. Newman, MD, Winston-Salem,NC J.L. Berry, MS C.M. Ferrario, MD W.D. Routh, MD R.H. Dean, MD PURPOSE: We designed a new expandable metallic stent and compared its performance to that of the Palmaz stent in canine iliac arteries. MATERIALS AND METHODS: The prototype stent and a Palmaz P154M stent were each balloon deployed to an 8-mm diameter in the opposite iliac arteries of five adult mongrel dogs. The expanded experimental stent has 7% more open area and 66% less metallic surface area than the Palmaz stent and does not foreshorten during expansion. At 6 weeks following implantation, all stents were reevaluated with arteriography and pressure gradients. The stents were then explanted and examined pathologically. RESULTS: No arteriographic evidence of migration or mechanical deformation and no significant pressure gradients were detected with either device. No evidence of exaggerated neointimal hyperplasia was noted within either of the stents. CONCLUSION: This preliminary study suggests that our experimental stent design is conceptually sound and that the new stent performs as well as the Palmaz stent in normal canine arteries. A potential design advantage of the new stent is its lack of foreshortening during deployment, which may enhance precision of placement and could be a desirable feature were the stent used as a component of an endoluminal graft.

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3 2 : 1 5 ~ ~ New Stent Prototype: Comparison with Current Devices and in Vivo Analysis of Peripheral Applications A.B. Fontaine, MD, Columbus, OH D.G. Spigos, MD H. Khabiri, MD A.S. Urbaneja, MD PURPOSE: Evaluation of a new balloonfstent prototype (Cook) for possible improvements in fluoroscopic conspicuity, nominal diameter, flexibility, and hoop strength, relative to the Palmaz stent and the Wallstent. In addition, in vivo vascular (arterial) evaluation was performed, including femoral and iliac locations. MATERIALS AND METHODS: Radiographs were obtained of the prototype stent, the Palmaz stent, and the Wallstent on metallic phantoms for evaluation of fluoroscopic conspicuity. Nominal diameter was evaluated by calibration of 12-mm mounted stents. Flexibility was evaluated by manually bending mounted stents, and hoop strengths were calculated by an electronic load cell device. Prototypes were then placed percutaneously in 10 swine arteries (five iliac, five femoral). RESULTS: Regarding fluoroscopic conspicuity, the prototype was superior to both the Palmaz stent and the Wallstent. The prototype stent was superior to the Palmaz stent with respect to nominal diameter and flexibility, and superior to the Wallstent with respect to hoop strength. The prototype was equivalent to the Wallstent with respect to profile and flexibility, and displayed hoop strength similar to that of the Palmaz stent. It was easily placed in the peripheral locations of the femoral ( n = 5) and iliac ( n = 5) arteries. CONCLUSION: The new balloonfstent prototype demonstrates a low profile and broad expansion diameter (including 12 mm through a 7-F sheath), is flexible while retaining high hoop strength, and is easily placed for peripheral applications due to its high fluoroscopic visibility and simple balloon expansion capability. 4 2:30 PM Bulk Elastic Behavior of Vascular Stents J.L. Berry, MS, Winston-Salem, NC V.S. Newman, MD C.M. Ferrario, MD W.D. Routh, MD R.H. Dean, MD PURPOSE: A comparative study of three commercially available stents and one new prototype stent was conducted to determine their bulk elastic behavior, one of the structural properties that may affect long-term stent patency. MATERIALS AND METHODS: A comparison of deformation characteristics was made between the

Palmaz stent, the Wallstent, the Gianturco stent, and an experimental stent developed by the authors. Each stent was deployed within a transparent elastomeric tube. The tube was then placed into a pressure chamber such that the outer wall was subjected to increasing hydraulic pressure while the lumen remained exposed to atmospheric pressure. The transmural pressure differential was measured with a transducer and the cross-sectional luminal area within the stent was recorded with a digital video system. The change in cross-sectional area, AA, was then plotted against the incremental pressure increases, AP. A linear regression analysis was applied to all pressurelarea data within the elastic regions of deformation. The slope of the regression fit to the stent deformation data was determined as a representation of the compliance of the stented segment. RESULTS: The self-expanding stents (Gianturco and Wallstent) differed in compliance by only 15%. The Palmaz stent was 4.5 times stiffer than the self-expandable stents under a uniform compressive load. The experimental prototype stent was 34% stiffer than the Palmaz stent. CONCLUSION: A simplified experimental protocol was designed and employed for the objective assessment of the bulk elastic behavior of metallic stents. In this in vitro model, the experimental prototype stent exhibited 34% greater stiffness than the Palmaz stent, which was substantially stiffer than the two self-expanding stents tested. Accurate, objective assessment of the bulk elastic behavior of vascular stents may be of value in optimizing stent design and performance, since stent rigidity may affect long-term patency.

5 2:45 PM New Cordis Tantalum Balloon-expandable Peripheral Vascular Stent: Design Features and Properties G.J. Becker, MD, Miami, FL R.J. Cottone, Jr A. Nguyen PURPOSE: To introduce the design features of the new Cordis tantalum balloon-expandable peripheral vascular stent and determine stent shortening, area of endothelial coverage underlying the stent, and hoop strength. MATERIALS AND METHODS: The stent is manufactured from a single 0.0075-inch-diameter 5400 grade tantalum wire formed into a single-plane sinusoidal wave pattern. The resulting planar "ribbon" is wrapped in a helical fashion to form a tube, the shape of which is maintained by welded joints that connect tangential intersections of adjacent

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sine wave apices. Consecutive weld joints form a "spine"; multiple spines may be located along the long axis of the stent. At each end, the stent has an end weld termination. Deployed diameters range from 4 to 12 mm, and deployed lengths from 15 to 70 mm. They are very radiopaque, low in profile, and flexible in the undeployed state. Stents 4-12 mm in diameter were expanded on Opta-5 balloon catheters. Shortening was determined (expanded lengthlunexpanded length x 100%).The area of endothelial coverage was determined as the percentage of open (nonmetal) area underlying the stent. Hoop strength was assessed in a pneumatic hoop strength testing device: Stents were expanded in a latex tube (1.1:l or 1.2:l stent-tube ratio) chosen to simulate normal human arterial compliance. Stented tubes were placed into a test cylinder; increasing pressure was applied external to the tubing in 0.1-psi increments. The limit of hoop strength was said to have been reached when the pressure caused a 70% or greater collapse of the stent. Results were compared with those published for other stents. RESULTS: In all sizes, stents shortened less than 25% and uniformly toward the center. The area of endothelial coverage ranged from about 80% to over 85%. Hoop strength was over 700 mm Hg in the deployed state, a level significantly greater than that of the Strecker stent and Wallstent, and slightly less than that of the Palmaz stent. CONCLUSION: This new balloon-expandable stent has a unique combination of high radiopacity, flexibility in the undeployed state, minimal shortening with expansion, large area of endothelial coverage, and excellent hoop strength. The results of preclinical testing will determine its suitability for human clinical trials. 6 3:OO PM Evaluation of the New Cordis Tantalum Balloon-expandable Peripheral Vascular Stent in Canine Arteries G.J. Becker, MD, Miami, FL R.J. Cottone, Jr T. Scagnelli, MD J. W. Bancroff, MD S.M. ROWland, PhD * J.L. Halgowich, et a1 PURPOSE: To assess the deployment performance of the new Cordis tantalum balloon-expandable peripheral vascular stent, and to evaluate it angiographically and histologically in healthy canines. MATERIALS AND METHODS: Thirty-three stents were deployed in peripheral, visceral, and brachiocephalic arteries in 14 adult mongrel dogs via carotid or femoral cutdown after administration of isoflurane anesthesia. Stents precrimped on Opta-5 PTA

balloons were delivered via 8.0-F (4-, 7-, 8-, and 9mm-diameter stents) or 8.5-F (10- and 12-mm-diameter stents) sheaths and deployed by an inflation device with a digital pressure monitor. Deployment scores (0-20 scale, 20 highest) graded ease of introduction, tracking through sheath into target site, stent visibility, stent architecture, and balloon deflationlremoval. Points were subtracted for sDasm, dissection, thrombosis, balloon rupture, stent migration, and stent deformity. Animals were pretreated with parenteral enrofloxacin and aspirin, and aspirin was continued until the animals were killed. During all predeployment, postdeployment, and antemortem angiograms, activated clotting times were maintained at two to three times baseline with intravenous heparin. Angiomorphometry, initially supplemented with intravascular US, enabled stent selection (stent-artery diameter ratio of 1.1:l or 1.2: 1). The explant was as follows: death by potassium chloride (14 days; 1, 3, and 6 months) follows cannulation of the aorta; the vasculature is rinsed with heparinized (2 UImL) lactated Ringer's solution and fixed with 3 L of Trump-McDowell solution a t 80 mm Hg. Stented and adjacent arterial segments are explanted and evaluated by means of inspection, radiography, and light and election microscopy for stent deformity, hemorrhage, inflammation, thrombosis, dissection, rupture, and neointima. RESULTS: Thirty-two of 33 deployment attempts were successful. Deployment scores ranged from 17 to 20. All stents were highly radiopaque and resistant to recoil. Stent architecture was uniform (31 of 32) and position stable (31 of 32). Fourteen stents have been harvested from six animals (3 months, n = 9; 1 month, n = 4; 14 days, n = 1). All stented vessels have been patent at predeath angiography. Histology to date has revealed partial or complete coverage of stent wires with neointima, patency of the stented vessels and branches, an approximate 10% reduction in lumen diameter due to neointima at 1 month, and no rupture or aneurysm. CONCLUSION: The stent is highly radiopaque and balloon expandable. It resists elastic recoil, incorporates into canine arterial walls as do other stents, and, in early studies, does not cause serious complications. Further results will determine the suitability of the device for human trials.

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Sunday, March 26 Room 305 Scientific Session 2 MR Angiography MODERATOR:

John A. Kaufman, MD, Boston, MA

1:45~~ Gadolinium-enhancedMR Angiography of Abdominal Aortic Aneurysms M.R. Prince, MD, PhD, Ann Arbor, MI D.L. Narasimham, MD M.V. Marx, MD D.M. Williams, MD W.T. Jacoby, MD K.J. Cho, MD, et a1 PURPOSE: A gadolinium-enhanced MR angiographic technique was developed for resolving all preoperative imaging questions concerning abdominal aortic aneurysms. MATERIALS AND METHODS: A combination of TI-weighted, 3D time-of-flight, 2D time-of-flight, and phase-contrast pulse sequences optimized for aortoiliac and visceral artery imaging at 1.5 T in a body coil was developed. The four sequences were performed with gadolinium to increase the image signal-to-noise ratio and compensate for the slow flow within the aneurysms. Blinded MR interpretations were correlated with angiographic or surgical findings in 24 patients. RESULTS: MR angiography correctly demonstrated the maximum aneurysm diameter, its proximal and distal extent, and the presence and location of thrombus in every patient. One leaking and one inflammatory abdominal aortic aneurysm were correctly diagnosed. MR angiography identified 23 significant stenoses, with a sensitivity of 96% and a specificity of 98% in 113 visceral or iliac branches with correlation. It did not reliably identify small accessory renal, inferior mesenteric, lumbar, or internal iliac arteries. No patient had a reaction to contrast material or contrast-induced renal failure. CONCLUSION: Gadolinium-enhanced MR angiography has the potential to replace both angiography and CT for preoperative imaging of abdominal aortic aneurysms in many patients. 7

Three-dimensionalPhase-ContrastMR Angiography of the Renal Arteries: Comparison with Aortography A.S. Gomeq MD, Los Angeles, C A H. Yoon, MD, PhD S.D. Flamm, MD S.C. Goodwin, MD PURPOSE: To compare the results of 3D phase-contrast MR angiography and aortography in the evaluation of the renal arteries.

MATERIALS AND METHODS: Thus far 25 patients have undergone 3D PC MR angiography and contrast aortography. MR angiography was performed with a Signa 1.5-T unit (TRPTE, 34lminimum; 1.5-mm section thickness; flip angle, 20"; VENC, 40 cm/sec; matrix, 256 x 128; one signal averaged; field-of-view 24-28 cm with an inferior saturation band). RESULTS: Diagnostic 3D PC MR angiographic studies were obtained in all patients. The number of renal arteries was correctly identified with MR angiography in 20 patients (80%). Five patients had multiple renal arteries, and the number of renal arteries was correctly identified in three of them. Five patients had a renal artery stenosis. Three patients with less than 50% stenosis at angiography were diagnosed as normal or with minimal disease a t MR angiography. One greater than 50% stenosis of an accessory renal artery was misread a t MR angiography as normal. In two patients with normal renal arteries, a stenosis of over 50% was diagnosed with MR angiography. CONCLUSION: Currently, neither the sensitivity nor specificity of 3D PC MR angiography appear sufficiently high to recommend its use as a single diagnostic procedure in renal artery disease.

MR Angiography of the Aortoiliac System: Prospective Comparison of Contrast-enhanced 3D and 2D Time-of-FlightTechniques G.A. Holland, MD, Philadelphia, PA R.A. Baum, MD E. Danhey, MD J.P. Carpenter, MD C. Cope, MD L. Axel, MD, PhD PURPOSE: The purpose of this study was to compare 2D time-of-flight (TOF) with 3D TOF MR angiography of the aortoiliac system. MATERIALS AND METHODS: The aortoiliac system was studied in 30 patients wtih contrast angiography and 2D TOF and 3D TOF MR angiography. The order of the studies was randomized, and all studies were performed within 72 hours of one another. All MR imaging studies were performed a t 1.5 T. For 2D TOF imaging, the following parameters were used: inferior saturation, TWTE of 3317, 60" flip angle, and 2-mm-thick sections. Coronal 3DTOF images were obtained before and after intravenous administration of gadolinium (0.2 mmollkg), and the following parameters were used: no saturation, TRPTE of 1012, 60" flip angle, and 1.8-mm-thick sections. The MR and contrast angiograms were read by three radiologists in a blinded fashion. Contrast angiography was the gold standard.

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RESULTS: There were 18 angiographically identified stenoses measuring at least 50%. Two-dimensional TOF MR angiography identified 18 lesions with review of source images, and three additional lesions were incorrectly detected in horizontal segments of vessels (sensitivity, 100%; specificity, 75%). Three-dimensional TOF MR angiography correctly identified all 18 lesions and overgraded one additional lesion as clinically significant (sensitivity, loo%, specificity, 91%). CONCLUSION: Three-dimensional TOF is more specific than 2D TOF MR angiography for the evaluation of the horizontal segments of the aortoiliac system and can be performed in half of the time. Interpretations and Treatment Decisions Based on MR Angiography Compared with Those Based on Conventional Arteriography in Symptomatic Lower Extremity Ischemia J.J. Snidow, MD, Indianapolis, IN V.J. Harris, MD S. 0. Trerotola, MD D.F. Cikrit, MD S. G. Lalka, MD M.S. Johnson, MD PURPOSE: To determine the frequency with which treatment plans based on MR angiography match those based on conventional x-ray arteriography in the evaluation of symptomatic lower extremity ischemia. MATERIALS AND METHODS: Two-dimensional time-of-flight (TOF) MR angiography was performed in 42 patients undergoing conventional arteriography for evaluation of symptomatic lower extremity ischemia. The blind interpretations and treatment plans based on MR angiography were compared with those based on arteriography, with arteriography used as the gold standard. RESULTS: For identification of hernodynamically significant stenosis or occlusion, the sensitivity and specificity, respectively, of MR angiography were 100% and 22% for iliac segments, 100% and 82% for common femoral segments, 89% and 65% for superficial femoral segments, 100% and 88% for popliteal segments, 92% and 91% for tibioperoneal segments, and 50% and 78% for deep femoral segments. The treatment plan based on MR angiography matched that based on arteriography in 41% of patients. CONCLUSION: For evaluation of symptomatic lower extremity ischemia, 2D TOF MR angiography cannot be considered a reliable substitute for conventional arteriography in patients who lack contraindications to the latter.

Peripheral Vascular Surgery with MR Angiography as the Sole Preoperative Imaging Modality R.A. Baum, MD, Philadelphia, PA J.P. Carpenter, MD G.A. Holland, MD PURPOSE: To determine if vascular reconstructions could be planned and accomplished based on MR angiography alone. MATERIALS AND METHODS: Eighty consecutive bypass candidates with ischemic rest pain or tissue loss were studied with preoperative outpatient MR angiography of the juxtarenal aorta through the foot. No contrast arteriograms were obtained preoperatively. Confirmation of MR angiographic findings was provided by intraoperative intraarterial pressure measurements for proximal vessels and postbypass arteriography for the runoff. RESULTS: Two patients could not tolerate MR angiography and required contrast arteriography, but all others underwent reconstructive procedures based on MR angiography alone (11aortofemoral, 67 femoral-popliteal-tibial). Intraoperative findings regarding suitability of inflow and outflow vessels confirmed the accuracy of MR angiograms in every case. MR angiography indicated that one of the infrainguinal bypass patients had significant inflow occlusive disease, and this was confirmed at operation with pressure measurements of inflow vessels that were always within 10 mm Hg (peak systolic) of systemic pressure. Intraoperative completion arteriograms and preoperative MR angiograms were identical for all but two patients, who had minor discrepancies. All aortofemoral reconstructions remain patent and all limbs intact. The femoral-popliteal-tibia1 reconstructions have 84% limb salvage and 78% graft patency rates a t 21 months. CONCLUSION: MR angiography is a noninvasive, cost-effective outpatient imaging technique that, if properly performed and interpreted, is sufficient for planning peripheral bypass procedures. Its use may supplant contrast arteriography in many patients.

MR Angiography in Patients with TIPS G.A. Holland, MD, Philadelphia, PA 2.J. Haskal, MD L. Dougherty, MS R.A. Baum, MD C. Cope, MD L. h e l , MD, PhD PURPOSE: To evaluate the utility of MR imaging

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in monitoring patients with TIPS. MATERIALS AND METHODS: Serial MR imaging was performed in 22 patients with TIPS. Seven patients were studied before and after TIPS. Other pa-

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tients underwent imaging a t 1 week, 3 months, and 6 months after TIPS placement. Imaging was performed with patients in the fasted state. A torso multicoil was used at 1.5 T for TI, T2, and 2D timeof-flight MR venography (5.3 Signa). Portal venous flow was measured with cine two phase-contrast imaging (velocity encoding 30 and 40 cmlsec,) and with a new technique using press localization with oscillating gradient for blood velocity determination (written by L.D.). Contrast studies were performed within 48 hours of MR imaging and served as the gold standard. RESULTS: Four patients were lost to follow-up:two due to the use of metallic coils for embolization, one due to severe encephalopathy, one due to death. MR imaging performed before TIPS revealed the following: cavernous transformation of the portal vein (n = 2), dilated intrahepatic ducts due to a stone in the common bile duct, Budd-Chiari syndrome (n = 11, nondiagnostic findings due to massive ascites (n = 2). Decreased varices were noted in all three patients who underwent imaging before and 24 hours after TIPS. Follow-up examinations at 3 and 6 months revealed four malfunctioning TIPS due to the following: hepatic vein stenosis (n = 11, TIPS occlusion (n = 11, and TIPS stenosis (n = 4). Increased varices and coronary venous flow was noted in all four patients, but no significant decrease was noted in portal venous flow with either phase-contrast imaging or blood volume determination. CONCLUSION: MR imaging may be useful in monitoring TIPS patients by identifying increases in varices.

Sunday, March 26 Room 304 Scientific Session 3 Biopsy MODERATOR:

Steven L. Dawson, MD, Boston, MA

Transjugular Liver Biopsy: An Effective and Safe Method of Obtaining Liver Tissue in High-Risk Patients K.W. Sniderman, MD, Toronto, Ont M.E. Simons, MD E.Y. Yeung, MD R.F. Colapinto, MD PURPOSE: To review the results of transjugular liver biopsy (TLB) performed with use of the Colapinto technique.

MATERIALS AND METHODS: At the Toronto Hospital, absolute indications for TLB are coagulopathy and ascites. A retrospective review of all TLBs performed between 1980 and 1990 was conducted. (A further 546 were performed in 1991-1993.) We examined the number of patients in whom TLB was attempted, the number of technically successful procedures, reasons for failure, complications, and pathologic diagnoses. RESULTS: Of 956 attempted biopsies, 926 were technically sucessful. Inadequate tissue samples for diagnosis were obtained in 26 patients. The procedure was unsuccessful in 30 due to puncture site complications (n = 141, hepatic vein anatomy (n = 7), capsular perforation (n = 51, other organ biopsy (n = 31, or lack of cooperation from the patient (n = l). Complications (n = 44) included carotid artery puncture (n = 6), neck hematoma (n=3), local anesthesia complication (n = 11, nausealvomiting (n = 11, and hepatic laceration (18 intraparenchymal, 15 extracapsular with 11 embolizations). No patients died as a result of TLB. Pathology reports are available in 873. Common diagnoses were cirrhosis (n = 5191, alcoholic hepatitis (n = 92), viral hepatitis (n = 881, toxic liver failure (n = 31), fulminant hepatic failure (n = 511, and neoplasms (n = 24). We shall discuss our technique with respect to safely obtaining adequate tissue samples. CONCLUSION: TLB with the Colapinto technique is a safe, effective method of obtaining tissue in high-risk patients with coagulopathies or ascites.

False-Negative Liver Biopsy Results in 553 Cases: Frequency, Features, and Contributing Factors B.L. Murphy, MD, Boston, MA P.F. Hahn, MD, PhD S.N. Goldberg, MD M.J. Lee, MD P.R. Mueller, MD S.L. Dawson, MD PURPOSE: To determine the attributes of false-negative percutaneous liver biopsy. MATERIALS AND METHODS: Electronic record search identified 553 biopsies performed in 494 patients over 6 years. Of these, 338 (61.1%)biopsy specimens were positive for neoplasm, 180 (32.5%) were negative or nondiagnostic, and 35 (6.3%)were equivocal. Thirty-four negative specimens (18.9%) were proved falsely negative at repeated biopsy (n = 14) or surgery (n = 20), with the remainder considered truly negative by surgery, autopsy, or clinical course. An extrahepatic primary malignancy was known in 319 patients (64.6%)prior to biopsy.

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RESULTS: The rate of false-negative biopsy specimens in patients with a preexisting malignancy was 7.0% (16 of 2301, compared with 12.7% (18 of 142) in patients with no known primary tumor ( P < .03). False-negative specimens occurred in 8.4% of epithelial tumors (24 of 322), compared with 18.8% of lymphomas (three of 16) and 18.4% of sarcomas (seven of 38) ( P < .05). CONCLUSION: The most important factor contributing to a false-negative finding a t imaging-guided liver biopsy is the absence of a known primary. Lymphoma and occult sarcoma have a higher incidence of false-negative biopsy than epithelial tumors, and this should be considered when a patient with a definite liver lesion undergoes a biopsy with negative results.

Transvenous Forceps Liver Biopsy M. W. Mewissen, MD, Milwaukee, WI E.B. Cohen, MD M.R. Crain, MD R. Paz-Fumagalli, MD R.A. Beres, MD R.A. Wertz, MD, et a1 PURPOSE: To review our experience with transvenous forceps liver biopsies (TFLBs) in patients with contraindications to conventional liver biopsy. MATERIALS AND METHODS: One hundred consecutive TFLBs were performed in 86 patients in whom transabdominal liver biopsy was contraindicated. Sixty-six TFLBs were requested in patients who had undergone bone marrow transplantation to evaluate for possible graft-versus-host disease, venoocclusive disease, leukemic infiltrate, and/or infection. The remaining 34 TFLBs were performed to clarify clinically suspected entities such as cirrhosis, carcinoma, Budd-Chiari syndrome, lymphoma, liver transplant rejection, and portal hypertension of unknown cause. Flexible biopsy forceps were introduced coaxially through an 8-F curved sheath previously placed into the right hepatic vein via the femoral vein. To satisfy pathology and culture requirements, multiple "bites" were obtained simply by reinserting the forceps through the sheath. RESULTS: Tissue judged adequate for histologic interpretation was obtained in 91 biopsies (91%). There were nine failures (9%), due to thrombus formation in the vascular sheath in one case or to inadequate tissue sampling in eight. There were no complications. CONCLUSION: TLBF is extremely safe and provides diagnostic information in critically ill patients in whom transperitoneal liver biopsy is contraindicated.

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Transjugular Liver Biopsy: Experience with the Quick-Core Biopsy Needle in 17 Patients A.F. Little, MD, Pittsburgh, PA A.B. Zajko, MD P.D. Orons, DO PURPOSE: Hepatic biopsies via the transjugular approach are indicated in those patients with coagulopathy, thrombocytopenia, and/or massive ascites. However, the biopsy specimens obtained have often been suboptimal due to the limitations of the biopsy needles previously available. We report our experience with the 18-gauge Quick-Core transjugular biopsy needle. MATERIALS AND METHODS: Between January and September 1994, 17 patients underwent transjugular liver biopsy with the Quick-Core needle. Patients were referred for a transjugular approach when significant coagulopathy and thrombocytopenia were present. Dimensions and adequacy of the biopsy sample were determined from the pathology report. Immediate procedural complications were recorded. Delayed complications (within 48 hours) were evaluated from the patient's chart. Complications were classified as minor (pain, transient hypotension) or major (those requiring surgery or blood transfusions). RESULTS: A total of 44 biopsy specimens were obtained. No immediate or delayed complications of either minor or major categories were observed. A pathologic diagnosis could be made from all specimens submitted, and no repeated biopsies were required. In only one instance was the specimen considered suboptimal due to crush artifact, but this did not affect the pathologic interpretation. CONCLUSION: The Quick-Core biopsy system produces consistently satisfactory and reproducible specimen cores, with morbidity and complication rates comparable to those with other biopsy systems.

Prospective Diagnosis of Lymphoma by Using Percutaneous Needle Biopsy R.C. Sheley, MD, Portland, OR H.A. Nelson, MD T.A. Demlow, MD S.F. Quinn, MD PURPOSE: This is a prospective evaluation of the diagnostic accuracy of percutaneous needle biopsies in the original diagnosis of lymphoma. MATERIALS AND METHODS: In 38 patients, the diagnosis of lymphoma was made for the first time. Biopsies were performed with either a cutting ( n = 36) or a n aspiration-type ( n = 2) needle. Immunochemistry studies were performed in 89% of

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patients (34 of 38) and flow cytometry was performed in 21% (eight of 38). The patients were followed up to see if the biopsy results were used for treatment or if additional material was obtained with an open surgical procedure. RESULTS: With treatment decisions used as the standard of reference, the accuracy of needle biopsies was 82% (31 of 38). In the other seven patients, the needle biopsy specimens were considered nondiagnostic or suspicious, or the oncologist wanted more tissue before initiating therapy. None of the patients responded to therapy in a manner that suggested their diagnosis was anything other than lymphoma. CONCLUSION: In this prospective study, needle biopsy specimens provided enough tissue to make the original diagnosis of lymphoma in 82% of patients.

Percutaneous Transpedicle Biopsy of the Spine W.N. Crow, MD, Galveston, TX A. Hadipavlou, MD G. Chaljub, MD S. Arya, MD A. Eyal, MD D.S. Willig, MD PURPOSE: A percutaneous technique of transpedicle biopsy was developed to rival conventional biopsy techniques. The results of 30 procedures performed with use of this technique are presented. MATERIALS AND METHODS: The percutaneous procedure requires a high-resolution image intensifier with C-arm rotation capabilities. The image intensifier is rotated such that a "bull's-eye" view of the pedicle is obtained. Local anesthesia is achieved with 1%Xylocaine along the intended tract. A small guide pin is oriented collinear with sagittal and axial pedicle angles and concentric with the center of the bull's eye. The pin is advanced through the pedicle into the vertebral body with subsequent coaxial passage of a "toothed" bone-cutting biopsy needle into the lesion. Tissue is obtained directly from the cutting needle as well as from curette and biopsy forceps passed through a cannulated sleeve. RESULTS: Adequate specimen for diagnosis was obtained in all 30 patients. There were no periprocedural complications. CONCLUSION: The technique of percutaneous transpedicle biopsy is safe, rapid, and effective. The caliber of the pedicle accomodated biopsy instruments that are able to access any vertebral body lesion and retrieve sufficient tissue for diagnosis.

Sunday, March 26 Room 316 Scientific Session 4 Dialysis Access Thrombectomy MODERATOR:

Scott 0 . Trerotola, MD, Indianapolis,

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In Vitro Percutaneous Balloon-assistedAspiration Thrombectomy in a Flow-CircuitClotted Dialysis Graft Model M.J. Sharafuddin, MD, S t Louis, MO S. Kadir, MD L.F. Haddad, MD T.P. Bocchini, MD PURPOSE: Percutaneous balloon-assisted aspiration thrombectomy (PBAT) was assessed in a flow model of clotted dialysis grafts. MATERIALS AND METHODS: Six polyvinyl tubes (30-cm length, 7-mm inner diameter) were filled with fresh human blood and allowed to clot at 4°C for 24-48 hours. Each tube was placed in parallel with a low-resistance bypass conduit and perfused with normal saline solution a t 50 mm Hg. Filters were interposed in the bypass conduit and outflow limb to trap "arterial" and "venous" emboli, respectively. The tip of a 7-F sheath was inserted in the "venous end" of the tube. A 4-F Fogarty balloon catheter, advanced through the sheath into the "arterial end," was inflated and withdrawn during sideport aspiration. RESULTS: Near-complete thrombectomy was achieved in all tubes (97%-100%). A single pass was sufficient in all but one. Substantial mechanical thrombolysis occurred from maceration and aspiration, with release of red blood cells into the effluent. Of the recovered particulate thrombus, the major fraction was aspirated (99%), while the venous embolic fraction was 0%-2%. No arterial embolization occurred. The mean aspirated volume was 50 mL (particulate, lysed clot, saline). The mean aspirated particulate clot volume was 1.75 mL (range, 1.252.5 mL). CONCLUSION: Mechanical thrombectomy with PBAT, in a clotted dialysis graft model, is feasible and substantially reduces venous embolus load compared with methods using a Fogarty balloon alone. Percutaneous Balloon-assisted Aspiration Thrombectomy of Clotted Dialysis Grafts S. Kadir, MD M. J. Sharafuddin, MD, St. Louis, MO PURPOSE: Mechanical thrombectomy of clotted dialysis grafts offers shortened procedure time and

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decreased cost and risks. We present our experience with percutaneous balloon-assisted aspiration thrombectomy (PBAT). MATERIALS AND METHODS: Thirteen PBATs were performed on freshly clotted dialysis grafts. A 4-F Fogarty balloon catheter was used through a 7F single venous-end sheath or crossed sheaths. The inflated balloon was withdrawn while side-~ortsuction was applied. Passes were made until no further clot was retrieved. Angioplasty of underlying stenosis was performed in 10 procedures. Two venous stenoses required stent placement. RESULTS: With PBAT alone, graft thrill and patency was restored in five instances. In another six, supplemental pharmacologic thrombolysis (urokinase, 250,000 IU) was needed. In two others, failure of initial pharmacologic thrombolysis prompted PBAT. with successful revascularization. The average number of passes was five. The mean aspirated volume (blood + clot) was 80 mL. The mean procedure duration until completed thrombectomy was 90 minutes (range, 45-125 minutes). PBAT, used alone, reduced the procedure duration by half. There was no evidence of arterial or pulmonary embolism. Technical success (complete or near-complete thrombectomy) and clinical success (patency after 1week of dialysis) were achieved in all patients. All but two grafts remain primarily patent (follow-up, 4-17 weeks). CONCLUSION: PBAT of freshly clotted dialysis grafts is simple, safe, fast, and effective.

21 2:15p~ Thrombosed Dialysis Grafts: Experience with Percutaneous Mechanical Declotting in 59 Cases M.A. Amygdalos, MD, Philadelphia, PA M.R. Middlebrook, MD * M.C. Soulen, MD * R.A. Baum, MD * Z.J. Haskal, MD R.D. Shlansky-Goldberg, MD, et a1 PURPOSE: We report our experience with the mechanical declotting of 59 thrombosed dialysis grafts. MATERIALS AND METHODS: Thirty-eight patients had 59 episodes of dialysis graft thrombosis that were treated by means of percutaneous mechanical declotting. Thrombus within the graft was displaced into the central venous circulation either by using crossing balloon catheters to macerate and push clot centrally or by employing a balloon catheter introduced from the ipsilateral internal jugular vein to pull the clot centrally. Any significant arterial or venous stenoses were dilated. RESULTS: Clinical success, defined as successful dialysis for 1week following the procedure, was achieved in 71% of the grafts. Mean time for the

procedures was 116 minutes. Mean primary patency was 64 days (range, 11-385 days). No signs or symptoms of pulmonary embolism were noted during the procedures; however, one patient died of sepsis 4 days later from a presumed septic pulmonary embolism. A pulmonary embolus was documented in this patient with pulmonary angiography. CONCLUSION: Percutaneous mechanical declotting of dialysis grafts is fast and effective. The occurrence of a death in our series suggests that the procedure should not be performed in patients with suspected graft infection.

2:30 PM Percutaneous Mechanical Thrombectomy of Dialysis Fistulas: A Randomized Study R. Uflacker, MD, Charleston, SC P.R. Rajagopalan, MD I. Vujic, MD M.A. Chita, MD J.E. Stutley, MD P.S. Kilpatrick, R N PURPOSE: To evaluate the clinical application of the Amplatz mechanical thrombectomy (MT) device to declot occluded dialysis fistulas versus surgical thrombectomy (ST). MATERIALS AND METHODS: Twenty patients with occluded dialysis grafts were randomly selected to undergo either ST ( n = 10) or MT ( n = 10). Angiography followed the procedures in all cases, and Doppler US was performed a t 1 month. Pre- and postprocedure plasma free hemoglobin was determined in the MT series. RESULTS: The graft was successfully declotted with MT in all cases, with postprocedure patency of 70% a t 48 hours and 60% a t 30 days. The graft was successfully declotted with ST in 70% of cases, with patency of 70% a t both 48 hours and 30 days. Angioplasty andlor stent placement was performed in all MT cases. New fistula creation and reanastomosis were performed in 30% of the ST cases. There were significant changes in plasma free hemoglobin after MT in 30% of the cases. CONCLUSION: MT achieved successful removal of clots in all the patients with occluded dialysis fistulas and is comparable to ST. The 1-month follow-up showed similar results for ST and MT treatments. The limitation of MT is the underlying disease that caused the graft occlusion, mainly in the venous outlet. Additional procedures (angioplasty and stent placement) are necessary most of the time following MT. When the fistula cannot be treated adequately with ST because of venous outlet disease, a new fistula or a new anastomosis is easily created, potentially enhancing the surgical results, as opposed to MT. 22

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New Thrombolytic Brush Catheter in Thrombosed PTFE Dialysis Grafts: Preliminary Animal Study F. Castaneda, MD, Peoria, IL A.H. Cragg, MD P. Wyffels, MD J. Patel, MD M. Hayes, MD A. Mendez, MD, et a1 PURPOSE: To test the safety, efficacy, endothelial changes, and risks of pulmonary embolic events after the use of a new thrombolytic brush catheter in mature thrombosed polytetrafluoroethylene (PTFE) dialysis grafts. MATERIALS AND METHODS: PTFE femoral loop grafts were implanted in 12 canines 2-4 weeks before mechanical thrombosis was performed. The thrombus was allowed to consolidate for 24-72 hours in 11 animals and 7 days in one animal. Standard percutaneous cross access was performed in each limb. A soft nylon, low-speed, 6-mm-diameter brush, aided by periprocedural urokinase, was used for thrombolysis. The grafts, native vessels, and lungs were evaluated macro- and microscopically. RESULTS: Thrombolysis was complete, with the exception of a small segment between the crossing of the access vascular sheaths. The average time of lysis was approximately 15 minutes, and no difference was found with regard to length of thrombosis or amount of thrombus. No significant endothelial changes were noted, and no evidence of acute pulmonary embolus was found a t necropsy or histologic studies. CONCLUSION: This catheter offers a simple, safe, and faster means of recanalization of thrombosed PTFE dialysis grafts. Potential clinical applications are many and would include a decrease in morbidity, cost, and time required for recanalization. The need for intensive care or extended angiographic suite times would be avoided. These advantages would be very attractive in our current cost-conscious society.

Hybrid Therapy for Thrombosed Dialysis Grafts E.M. Walser, MD, Galveston, TX N.J. Finn, MD R.A. Morgan, MD G.R. Wittich, MD W.N. Crow, MD PURPOSE: Recent literature suggests that mechanical thrombectomy is effective for recanalization of occluded dialysis grafts. In the past, the standard approach was thrombolysis with urokinase therapy. Because mechanical thrombectomy can cause pul-

monary embolus and urokinase therapy alone is time consuming, we have fostered a combination of the two techniques. MATERIALS AND METHODS: This series involved 51 hemodialysis grafts that were thrombosed acutely. Multiple-side-hole catheters were placed directly into thrombosed polytetrafluoroethylene (PTFE) loop grafts. The thrombosed region was laced with urokinase by means of the pulsed spray technique. At the earliest sign of graft recanalization, that is, minimal flow of contrast material into the graft following arterial injection, a balloon catheter was used to macerate the remaining thrombus. The clot was then forced into the pulmonary circulation and angioplasty was performed if necessary. RESULTS: Forty-two (82%) of the procedures were successful and nine (17%) were failures. One failed procedure resulted in a n upper extremity hematoma. There were no other complications. The average time for each procedure was 105 minutes. CONCLUSION: Hybrid therapy for PTFE grafts, that is, thrombolysis in conjunction with thrombectomy and angioplasty, is successful in dialysis graft recanalization in 82% of our procedures. Complication rates are low, and procedure time is significantly less than that of thrombolysis alone.

.

Sunday, March 26 Room 316 Scientific Session 5 Angioplasty: Clinical Results Alan H. Matsumoto, MD, Charlottesville, VA

MODERATOR:

Superficial Femoral and Popliteal Arterial Angioplasty: Effect of Runoff on Long-term Patency-Results from the SCVIR Transluminal Arterial Revascularization Registry J.L. Groffsky, MD, Philadelphia, PA M.C. Soulen, MD PURPOSE: To evaluate the effect of runoff on longterm patency after femoropopliteal angioplasty. MATERIALS AND METHODS: The patency of 207 limbs in 194 patients who had undergone successful femoropopliteal angioplasty was prospectively monitored. Each runoff vessel was assigned a score: 0 (normal to 450% stenosis), 1 (50 to 99% stenosis), or 2 (occluded), then added, giving a total score of 0-6 for each limb. Long-term patency was deter-

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mined by means of clinical assessment, noninvasive studies, and/or angiography. Cumulative patencies and intergroup comparisons were calculated by using actuarial analysis and the log-rank test. RESULTS: The cumulative patency for all 207 limbs was 66.0% a t 3 years. For runoff groups, the 3-year cumulative patency was 86.1% for a score of 0, 75.0% for 1, 95.7% for 2, 33.3% for 3, 74.2% for 4, 12.6% for 5, and 30.2% for 6. There was a significant difference between groups 5 and 6 versus the remainder of runoff groups ( P < .0001). CONCLUSION: Runoff is a significant factor determining patency after femoropopliteal angioplasty. Patients with a t least one vessel free of significant disease or a t least two unoccluded vessels with 50%-99% stenoses do significantly better than those without. 26 4 : 1 5 ~ ~ Failure of Balloon Angioplasty in the Peripheral Arteries: Causes and Consequences R.I. Patel, MD, Philadelphia, PA G.A. Gardiner, Jr, MD J. Bonn, MD M.E. Donovan, R N PURPOSE: To document the prevalence, causes, and clinical significance of technical failure of balloon angioplasty in the peripheral arteries. MATERIALS AND METHODS: Data from a large multicenter trial of peripheral angioplasty (STAR Registry) were used for this study. Results from consecutively enrolled patients undergoing balloon angioplasty for stenotic lesions involving native lower-extremity arteries were reviewed. Technical failure was defined as residual stenosis of 50% or greater. RESULTS: Nine hundred forty-four balloon angioplasty procedures involving 534 patients were reviewed. Thirty-six technically unsuccessful procedures were reported (4%). The majority were infrainguinal in location (75%). A poor morphologic result despite successful balloon inflation was the single most common cause of failure (58%). The next most frequent cause was a complication occurring a t the angioplasty site (33%), most often vessel wall dissection. Four of six dissections were successfully treated by means of interventional techniques. One dissection resulted in arterial occlusion requiring surgical bypass. Another dissection did not require further treatment. Other causes of failure included inability to cross lesions with guide wire or catheter, failure to expand the angioplasty balloon completely, and spasm. CONCLUSION: Technical failure of balloon angioplasty for lower extremity native artery lesions was infrequent. Lesions unresponsive to balloon inflation

were the most important cause of failure. In no instance did failure result in emergency surgical procedures or preclude future treatment.

PTA and Thrombolysis in the Treatment of Leg Salvage A. Motarjeme, MD, Downers Grove, IL PURPOSE: To report the immediate and long-term results of PTA and thrombolysis performed for leg salvage. MATERIALS AND METHODS: Three hundred sixty-six limbs in 273 patients were treated to achieve leg salvage. The patients were classified according to the recommendations of the Ad Hoc Committee on Reporting Standards, Society for Vascular SurgeryINorth America Chapter, International Society of Cardiovascular Surgery. These patients suffered from a t least one of the following: ischemic resting pain, nonhealing ischemic ulcers, and/or gangrenous changes of the lower extremity, in addition to an ankle-brachial index 0.4 or less or a toebrachial index of 0.30 or less in diabetic patients. RESULTS: Of the 249 patients available for followup, total salvage was achieved in 181 patients (72.7%), 19 patients (7.6%) had small-part amputations, and four (1.6%) had transmetatarsal amputations. This constitutes a n 82% rate of limb salvage. Thirty-two patients (8.8%) had below-knee and 11 (3.6%) had above-knee amputations. With life-table analysis, the 5-year survival rate was 71%. CONCLUSION: PTA and thrombolysis are effective endovascular therapy for achieving leg salvage. The long-term leg salvage results are comparable to those of surgery, but the 5-year survival rate is superior.

PTA of Peripheral Arteries by Means of Retrograde Catheterization via the Popliteal Artery: A Series of 80 Cases M. Henry, MD, Essey Les Nancy, France M. Amor, MD G. Ethevenot, MD I. Henry, MD M. Allaoui, MD E. Le Borgne, MD, et a1 PURPOSE: To report our experience with the popliteal artery approach in treating superficial and common femoral artery lesions, especially after failure of antegrade femoral access. MATERIALS AND METHODS: In 80 symptomatic patients, the popliteal artery approach was used (3.2% of PTA procedures). The lesions were located in 63 superficial femoral arteries (six ostial lesions, 15 polystenotic lesions > 15 cm, 42 occlusions), 14

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common femoral arteries (nine stenoses, five occlusions), and three bypass grafts (three stenoses). The popliteal approach was used first in 53 patients and after failure of the antegrade femoral approach in 27 patients. Seven to 9-F introducers were used. RESULTS: Introducer placement was successful in all cases. The procedure failed in 11% of patients (nine of 80): seven in recanalization of occlusions and two because of elastic recoil. Local complications included two hematonlas and four arteriovenous fistulas. The overall success rate of the procedure was 89% (71 of 80). The rate of success after failure of the antegrade femoral approach was 85% (23 of 27 obstructed lesions). CONCLUSION: The popliteal approach is safe and effective and permits successful procedures after the antegrade femoral approach has failed. It deserves to be used more often to treat femoral lesions percutaneously. It enables "internal bypass" with stent grafts and covered stents.

Outpatient Percutaneous Endovascular Procedures J.H. Rundback, MD, Bethlehem, PA H.L. Folander, MD M.A. Granson, MD PURPOSE: To demonstrate the safety and efficacy of performing PTA and related endovascular interventions as outpatient procedures. MATERIALS AND METHODS: Since July 1993, 93 outpatient endovascular interventions were performed on 63 patients. There were 30 aortoiliac, 40 femoropopliteal, eight tibioperoneal, 14 peripheral bypass graft, and one venous procedure. Methods of access included 14 antegrade femoral puntures and one axillary puncture. Patients were observed in the ambulatory surgery unit for 4-6 hours after hemostasis was achieved. Written discharge instructions were provided, and patients were discharged home with adult supervision. Follow-up calls were made within 24 hours after the procedure. RESULTS: The technical success rate was 97% (90 of 93). Eleven patients were admitted: two who did not have an adult to accompany them home, three for a subsequent percutaneous intervention, three for thrombolytic therapy, two because of angioplasty site pseudoaneurysm, and one because of an iliac artery rupture requiring surgical repair. There were no delayed complications requiring treatment. CONCLUSION: Outpatient arterial endovascular procedures can be performed with a high success rate and low complication rate and may be a safe and effective alternative to routine admission.

Angioplasty for the Treatment of Mesenteric Ischemia M.J. Hallisey, MD, Hartford, CT H.S. Vine, MD S.K. Ohki, MD S.K. Sussman, MD J. Deschaine, BS J.J. Straub, Jr, MD, et a1 PURPOSE: To evaluate PTA in the treatment of mesenteric ischemia. MATERIALS AND METHODS: Over a 10-year period, 25 focal mesenteric stenoses were treated with PTA in 16 patients with acute or chronic mesenteric ischemia. There were 13 female patients and three male patients, and their mean age was 64.7 years (range, 54-79 years). Treated vessels included seven celiac arteries, 17 superior mesenteric arteries, and one inferior mesenteric artery. RESULTS: PTA was technically successful in 14 of 16 patients (87.5%).Nine of 14 (64.3%) demonstrated primary patency with relief of clinical symptoms at a mean follow-up of 2.3 years (range, 0.3-5 years). An additional three patients underwent successful repeated PTA for recurrent symptoms. There was one short-term (<30 days) death, and one patient subsequently underwent successful surgical bypass for recurrent mesenteric ischemia. CONCLUSION: Angioplasty of the mesenteric vessels may provide relief for selected patients with intestinal ischemia, but repeat dilation is needed in some patients. In treatment of mesenteric ischemia, better clinical results are achieved with PTA when more than one vessel is dilated.

Sunday, March 26 Room 304 Scientific Session 6 Embolotherapy: Visceral Richard D. Shlansky-Goldberg, MD, Philadelphia, PA MODERATOR:

Bleeding Associated with Pancreatic Disease I. Vujic, MD, Charleston, SC R. Uflacker, MD C.T. Reiheld, MD D. Adams, MD M.A. Chita, MD PURPOSE: This study was undertaken to review the role of interventional radiology in the treatment of vascular complications of pancreatitis. MATERIALS AND METHODS: A retrospective review was performed of 19 patients with arterial bleeding and 21 patients with venous bleeding due

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to left-sided portal hypertension caused by splenic vein thrombosis from 1979 to 1994. RESULTS: Eight of the 19 patients with arterial bleeding had definitive treatment with embolotherapy. Three underwent preoperative embolization, while the rest underwent surgery alone. Selection criteria for embolotherapy include the stability of the patient and location of the bleeding. The arterial bleeding sources included the gastroduodenal ( n = 6), splenic ( n = 6), leR gastroepiploic ( n = 21, inferior pancreatic ( n = 2), left gastric ( n = 1)right colic ( n = I), and transverse pancreatic ( n = 1)arteries. Venous bleeding was treated with preoperative emobolotherapy of the splenic artery with a balloon occlusion catheter in 10 of 21 patients, which resulted in significantly reduced mean operative blood loss at the time of splenectomy compared with surgery without embolization (1,730 vs 3,320 mL). CONCLUSION: Selective embolization may lead to complete control of bleeding, thereby obviating surgery and providing definitive treatment in patients with bleeding secondary to pancreatitis. Preoperative occlusion of the splenic artery prior to splenectomy significantly reduces operative blood loss.

Aneurysms of the Visceral Arteries: Review of Institutional Experience C.S. Payne, MD, Durham, NC KG. McDermott, MD P.V. Suhocki, MD E.R. Hudson, MD G.E. Newman, MD * T.P. Smith, MD PURPOSE: Historically, visceral artery aneurysms have been treated with surgical resection. Recently transcatheter embolization has been used, but the literature contains mostly single case reports. We present our institutional experience with visceral aneurysms in 11 patients, demonstrating the utility of interventional radiologic management in eight cases. MATERIALS AND METHODS: We retrospectively reviewed our cases that were limited to visceral aneurysms (including pseudoaneurysms). Renal artery aneurysms are not included. Selective angiograms were obtained in all patients, and coil embolization of the aneurysm or parent vessel was performed in eight patients. The radiologic and medical records were reviewed in an attempt to identify etiologic factors and to determine outcome following diagnosis. RESULTS: Cases identified include three superior mesenteric, one gastroduodenal, two splenic, six hepatic, and two celiac aneurysms in 11 patients. Eight cases were managed with transcatheter embolization of the aneurysm or parent vessel with im-

mediate technical success. One patient was successfully treated surgically. Two patients did not undergo intervention. CONCLUSION: We describe 11 patients with visceral aneurysms with case outcomes based on endovascular, surgical, or medical treatment. Our study demonstrates that endovascular therapies are becoming the treatment of choice for these entities.

33 4:30 PM Portal Vein Embolization with Steel Coils and Absolute Ethanol: Experimental Study with Canine Liver K. Yamakado, MD, Mie, Japan Y. Nishide, MD T. Hirano, MD K. Takeda, MD A. Nakatsuka, MD T . Nakagawa, MD PURPOSE: Portal vein embolization (PVE) is expected to be an adjuvant treatment of liver tumors. PVE was tried with two kinds of embolic materials, steel coils and absolute ethanol. The effects of each embolic material on the portal veins and the liver parenchyma were studied. MATERIALS AND METHODS: Five dogs were treated with coils and 12 with ethanol. The secondorder portal branches were embolized. RESULTS: PVE with coils achieved immediate occlusion of the embolized vessels in all dogs. Unexpectedly, unembolized vessels were also constricted andlor obstructed in four of five dogs treated with coils during a 4-week follow-up period. Histologic examination showed no hepatic necrosis in all dogs. By contrast, in the dogs treated with ethanol, venous occlusion was achieved immediately after embolization with ethanol doses of 0.4 mL/kg or more. The embolized vessels remained occluded, and no obstruction of unembolized vessels was observed until 4 weeks after embolization. Hepatic necrosis was observed in the segments where portal veins were occluded. The degree of parenchymal damage was proportional to the injected ethanol dose. CONCLUSION: Ethanol is probably more suitable than coils as an embolic material for PVE. PVE with coils might be dangerous because unembolized vessels might be occluded unexpectedly. For the clinical use of PVE with ethanol, the appropriate injected dose should be investigated.

.

34 4345 PM Chicken Chorioallantoic Membrane as a Model for Embolization L.S. Machan, MD, Vancouver, BC L. Arsenault, PhD W. Hunter, MSc, MD PURPOSE: To determine if embolic particles can be introduced into the arteries of a chicken egg chorio-

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allantoic membrane (egg CAM) and their distribution and effects observed. MATERIALS AND METHODS: The egg CAM is a dynamic living model that allows direct observation of blood vessel growth. It will support malignant implants, and malignant neovascularity can be directly observed. Twenty-four egg CAMS were embolized, four each with methylene blue, absolute alcohol, Gelfoam, Ivalon, polycaprolactone (PCL), and ethylene vinyl acetate particles. The immediate distribution of particles and temporal response to embolization were observed. RESULTS: Embolization and vascular occlusion was easily achieved with both liquids and the PCL particles, and was accomplished with practice with the remaining particles. Particle distribution is beautifully visualized, and arterial occlusion and regression easily seen. Commercially available particles are extremely variable in size, resulting in some difficulties with injection. CONCLUSION: The egg CAM is an excellent living model for observation of the effects of arterial embolization.

Transcatheter Embolization in the Management of Upper Gastrointestinal Hemorrhage: Laboratory and Clinical Factors Contributing to Success R.L. Duszak, Jr, MD, Philadelphia, PA M.C. SouZen, MD * R.D. Shlansky-Goldberg, MD * C. Cope, MD M.J . Pentecost, MD 2.J . Haskal, MD, et a1 PURPOSE: To evaluate laboratory and clinical factors contributing to the success of embolization for upper gastrointestinal hemorrhage. MATERIALS AND METHODS: Fifty-two patients with upper gastrointestinal hemorrhage underwent 56 embolization procedures. Etiologies included duodenal ulcer (n = 141, gastric ulcer (n = 81, gastritis (n = 7), Mallory-Weiss tear (n = 7), sphincterotomyl drainage (n = 7), anastomosis ( n = 6), malignancy (n = 4), arteriovenous malformation (n = 21, and pancreatitis (n = 1). Angiographic and endoscopic findings determined the arterial territory embolized: left gastric (n = 25), gastroduodenal (n = 251, or other (n = 6). Target vessel stasis and cessation of extravasation, when present, defined technical success. Bleeding cessation and hematocrit stabilization defined clinical success. RESULTS: The technical success rate was 96%. Bleeding recurred in 24 cases, between 3 hours and 15 days. Clinical success occurred in 11 of 32 (34%) procedures in patients with coagulopathy versus 19 of 24 (79%)without coagulopathy. Success did not

vary with embolic agent, target vessel, or presence (n = 26) versus absence (n = 30) of angiographic extravasation. Etiology affected success with rates as follows: duodenal ulcer, 43%; gastric ulcer, 38%; Mallory-Weiss tear, 71%; spincterotomyldrainage, 100%; anastomosis, 50%; and malignancy, 100%. Hospital mortality was 39% overall (coagulopathic, 66%; noncoagulopathic, 4%). No direct embolizationrelated complications were identified. CONCLUSION: Despite a high rate of technical success (96%), embolization controlled upper gastrointestinal bleeding in 54%. In patients with coagulopathy or gastritis, transcatheter management often fails. Embolization is equally effective in the absence of angiographic extravasation.

Transvascular Interventions in Patients with Small Bowel Hemorrhage G.R. Wittich, MD, Galveston, TX J .J . Bookstein, MD H. Eisenberg, MD E.M. Walser, MD R.A. Morgan, MD PURPOSE: The small bowel is not readily amenable to endoscopic intervention. Thus, angiographic diagnosis and possible transcatheter therapeutic interventions are often indicated in patients with acute or intermittent small-bowel hemorrhage. We present our experience in 53 patients. MATERIALS AND METHODS: Twenty-seven patients presented with active hemorrhage and 24

with a history of intermittent massive hemorrhage. Diagnostic angiographic work-up included studies of the superior mesenteric artery and celiac axis. In case of active hemorrhage, vasopressin therapy was usually initiated. In selected cases embolotherapy was performed with Gelfoam. RESULTS: Intraarterial vasopressin therapy was performed in 14 of 29 patients with active hemorrhage and was successful in 10 (71%). Embolization was successful in all 13 patients in whom it was performed. The remaining patients were treated by means of emergent surgery after preoperative angiographic localization of hemorrhage. In 14 of 24 patients (60%)without active hemorrhage, the source of bleeding was identified. Complications included transmural infarction in two patients. CONCLUSION: Selective angiography is now a well-established diagnostic tool for preoperative localization of small-bowel hemorrhage. Selective transcatheter therapy can be performed effectively with a relatively low risk of small-bowel infarction if emergent surgery is not indicated or is associated with very high risk.

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Sunday, March 26 Room 305 Scientific Session 7 Cancer: New Interventions MODERATOR:

Michael C. Soulen, MD, Philadelphia, PA

Cryosurgery for Prostate Cancer: Results in 300 Patients G. Casola, MD, San Diego, CA B.F. Stainken, MD E. van Sonnenberg, MD J.D. Schmidt, MD PURPOSE: To assess cryosurgery in the treatment of prostate cancer. MATERIALS AND METHODS: Three hundred men with biopsy-proved prostate cancer underwent transperineal cryoablation of the prostate. Endorectal US with a 7.5-MHz transducer was used to image the prostate, determine its volume, guide percutaneous technique, and monitor freezing. By means of the Seldinger technique, 11-F dilators and sheaths were inserted over an 0.038-inch J-tipped guide wire, initially placed through 18-gauge needles. Three-millimeter cryoprobes were placed through each sheath (maximum, five), and the entire prostate was frozen for 5-15 minutes by probe temperatures of -196°C. Follow-up biopsies were performed at 3-6 months following cryosurgery. RESULTS: The average age of the patients was 67 years. Eighty percent of the tumors were stage A and B. The only major complication was a urethralrectal fistula requiring surgical repair. Minor complications included hematuria (50%),ecchymosis (55%), scrota1 edema (30%),stress incontinence (14%), urinary obstructive symptoms (8%),and urinary tract infection (3.6%).These resolved shortly after the procedure with conservative therapy. Prostate biopsies a t 3-6 months in 100 patients were negative for cancer in 90% of cases. CONCLUSION: Early results suggest that percutaneous cryosurgery is effective in the treatment of prostate cancer and is associated with few significant complications. Long-term studies are ongoing. Percutaneous Transperineal Prostatic Cryoablation as an Adjunct or Salvage Procedure B.F. Stainken, MD, Albany, N Y G. Casola, MD J.D. Schmidt, MD I. Barkin, MD S.C. Rose, MD PURPOSE: To describe our experience with prostatic cryoablation in individuals with locally recurrent prostatic carcinoma after radiation therapy,

cryoablation, transurethral resection, and operative prostatectomy. MATERIALS AND METHODS: Prostatic cryoablation was performed with an array of three to five 3mm cryoprobes placed transperineally under transrectal US guidance with a modified Seldinger technique. One or two cycles of freezing were performed, and patients were followed up with biopsy and prostate-specific antigen (PSA) determinations at 3 and 6 months. RESULTS: Twenty-six of 300 cryoablation procedures performed in the past 18 months involved patients who had undergone another therapy for their biopsy-proved prostatic carcinoma (radiation in 11, cryoablation in four, TURP in nine, and operative prostatectomy in three). All procedures were technically successful. Postprocedure PSA and early biopsy results mirror those of the larger treated population. No major procedural complications occurred in this group. CONCLUSION: Transperineal US-guided percutaneous cryoablation of the prostate may be performed as an adjunct or salvage procedure for locally recurrent disease.

Intraoperative US-guided Cryosurgery for Liver Tumors: Techniques and Posttreatment Imaging R.A. Kane, MD M. Roizental, MD, Boston, M A J.B. Kruskal, MD PURPOSE: To describe our experience with intraoperative US-guided hepatic cryosurgery, including technique, complications, results, and findings on posttreatment imaging studies. MATERIALS AND METHODS: From 1985 until 1993, 62 patients underwent cryoablation of liver neoplasms, with liquid nitrogen (- 196°C) circulating through one or two cryoprobes. During continuous US monitoring, two freeze-thaw cycles were performed. A 1-cm margin was achieved beyond the tumor. CT was performed 1 week later and at 6month intervals thereafter. When possible, US or MR imaging was performed. RESULTS: The procedure was successfully performed in all patients. The range of follow-up was 3-88 months (mean, 22 months) in 49 patients. Overall, 26 patients are alive. Of 35 patients with no residual disease following cryosurgery, 22 (63%) are still alive. Major complications included capsule cracking with hemorrhage, wound dehiscence, and two subphrenic abscesses. No deaths have occurred from the procedure. All patients developed transient fever, leukocytosis, and elevated liver enzyme lev-

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els. Preliminary actuarial survival curves are similar to those for surgical resection. CONCLUSION: Intraoperative US-guided cryosurgery is an effective alternative method to treat nonresectable liver tumors.

High-Dose Percutaneous Ethanol Injection Therapy of Liver Lesions E.C. Unger, MD P. Granstrom, MD M.R. Baker, MD, Tucson, AZ PURPOSE: To evaluate the follow-up and outcome of patients treated with high-dose percutaneous ethanol injection (PEI). MATERIALS AND METHODS: Twenty-one patients with malignant hepatic tumors (three hepatoma, eight colon cancer, three melanomas, two leiomyosarcoma, two adenocarcinomas, one neuroendocrine pancreatic cancer, one pancreatic adenocarcinoma, and one renal cell cancer) underwent PEI. A total of 156 PEI treatments were performed under CT or US guidance, with a mean dose of 36 mL of ethanol administered through multiple 22-gauge spinal needles. The total volume of alcohol administered over multiple treatment sessions was determined with this equation: volume = 413 T (r+5I3, where r = tumor radius. Patients underwent liver biopsies and MR imaging before and after PEI. RESULTS: Sixteen of the patients completed courses of PEI. Seven of 16 had complete remission of their hepatic tumors (two hepatoma, three melanoma, one pancreatic neuroendocrine cancer, and one renal cell cancer). Complications of PEI included three cases of hepatic abscess and one case of hemorrhage, treated by percutaneous drainage and transfusion, respectively. CONCLUSION: PEI appears to be a n effective form of regional control of hepatic tumors. Hepatic abscess is a possible complication of high-dose PEI.

Combined CT and Angiography for Localization of Pancreatic Endocrine Tumors S.B. Oglevie, MD, San Diego, CA J.J.Bookstein, MD G. Casola, MD A.C. Roberts, MD K. Valji, MD PURPOSE: Endocrine tumors of the pancreas are frequently difficult to localize with preoperative US, CT, and standard angiogaphy. We investigated the accuracy of combined CT and angiography for localization of these tumors. MATERIALS AND METHODS: Seven patients with suspected endocrine tumors of the pancreas were

referred for localization. All patients were evaluated with US and thinly collimated CT, with and without intravenous contrast medium. Pancreatic angiography was then performed. The angiographic catheter was left in the celiac artery and the patients were transferred for CT. After noncontrast scans were obtained, CT images were obtained during the intraarterial infusion of contrast material. The accuracy of these preoperative localization techniques was determined by comparison with operative and histopathologic findings. RESULTS: CT combined with angiography accurately localized pancreatic endocrine tumors and excluded hepatic metastatic disease in all six patients with surgically proved tumors. The average lesion size was 1.9 cm (range, 5-3.0 cm). These lesions were not detected with preoperative US in three patients, not detected with CT in three, and not detected with pancreatic angiography in two. There were no complications associated with combined CT and angiography or angiography alone. CONCLUSION: CT combined with angiography is highly accurate for the localization of small pancreatic endocrine tumors. The combined technique is more sensitive than preoperative US, CT, or standard angiography. This technique should be employed in those patients with clinically suspected pancreatic endocrine tumors, in whom US and CT fail to demonstrate a lesion. I t is technically easier, safer, and thought to be more accurate than portal venous sampling in this difficult group of patients.

Malignant Insulinoma: Preliminary Results with Permanent Hepatic Artery Embolization of Liver Metastases F.W. Winkelbauer, MD, Vienna, Austria B. Niederle, MD R.H. Wildling, MD S.A. Thurnher, MD J. Lammer, MD PURPOSE: To evaluate permanent hepatic artery embolization of liver metastases after malignant insulinoma as a therapeutic procedure. MATERIALS AND METHODS: Three female patients had persistent severe hypoglycemia after distal pancreatectomy because of a malignant insulinoma. US, CT, and CT portography demonstrated multiple hypervascular metastases 0.5-3 cm in diameter in both lobes of the liver. Unilobar sequential transcatheter embolization of the hepatic artery was performed. Permanent occlusion was achieved by using a mixture of n-butyl-cyanoacrylate and ethiodized oil as the embolizing agent.

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RESULTS: In all patients, embolization of the hepatic artery was technically feasible and complete occlusion could be obtained. CT portography was performed for follow-up and revealed a marked decrease in tumor size of more than 50% 3-6 weeks after complete arterial occlusion of the liver. All patients improved within days after the procedure, as confirmed by a decrease in measurable hormone levels and amelioration of symptoms. Two patients are still alive 20 and 27 months after the first embolization. Current investigations revealed normal laboratory data and no further tumor progression in the liver. The third patient died 15 months after the first embolization. CONCLUSION: Hepatic arterial embolization appears to be a n effective means of palliation for liver metastases of malignant insulinoma. Long-term improvement seems to be most likely the effect of extensive ischemia obtained from permanent occlusion.

Sunday, March 26 Room 315 Scientific Session 8 Vena Cava Filters MODERATOR: David J. Eschelman, MD, New Haven, CT

Accuracy and Safety of CO, Inferior Vena Cavomaphy K.L. Sullivan, MD, Philadelphia, PA J. Bonn, MD M.J. Shapiro, MD G.A. Gardiner, Jr, MD PURPOSE: The accuracy of CO, in determining IVC diameter prior to filter placement was compared with that of iodinated contrast material. The safety of CO, venography was also evaluated. MATERIALS AND METHODS: Consecutive patients undergoing inferior vena cavography before filter placement were prospectively evaluated with both iodinated contrast material and CO,. Blood pressure and arterial oxygen saturation were measured before and after CO, injection. Infrarenal IVC diameter was measured before and after CO, injection. Infrarenal IVC diameter was measured in the same four locations in each patient for both agents. Significance was defined as P < .05 and determined with the paired t test. RESULTS: Ten patients were enrolled during the first 4 months of the study. The mean blood pres-

.

sure was 129 + 17/70 + 13 mm Hg before CO, versus 124 & 14/70 12 mm Hg after CO, (not significant [NS]). Arterial oxygenation was 98% + 2% before versus 96% 8% after CO, (NS). There was a trend toward smaller IVC diameters with CO, (mean, 16.7 mm + 4.3) versus iodinated contrast material (17.9 mm + 3.3) (P = .054). CONCLUSION: There was no cardiopulmonary compromise from injection of CO, into the IVC. CO, may undersize the IVC compared with iodinated contrast material. Additional data from this ongoing study will be presented.

+

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In Vitro Evaluation of Guide-Wire Entrapment by Vena Caval Filters J.A. Kaufman, MD, Boston, MA J. W. Thomas, MD A. C. Waltman, MD S.M. Rivitz, MD S. C. Geller, MD PURPOSE: Filter dislodgement by guide wires is of clinical concern. An in vitro study of IVC filter entrapment of guide wires inserted from the jugular1 subclavian approach was conducted. MATERIALS AND METHODS: In a n IVC flow model (21-mm diameter), guide wires (0.038-inch straight, 15-mm J , 3-mm J , and 0.035 inch 1.5-mm J) were drawn 50 times each through all five commercially available IVC filters from a superior approach. The ways in which the filters engaged the guide wires were recorded. For each type of filter/ guide wire interaction recorded above, the force required to disengage the guide wire with traction was measured using a digital strain-gauge. RESULTS: All filters engaged curved guide wires. Guide-wire entrapment leading to structural failure of the filter without disengagement occurred in three specific configurations: the curve of a 1.5-mm J guide wire around a Vena Tech filter leg and the tips of 3-mm J and 1.5-mm J guide wires engaged in the hole a t the Vena Tech filter apex. In these cases structural failure of the filter occurred when the force on the guide wires exceeded 4.0 lb. All other filterlguide wire configurations disengaged with a force of less than 0.5 lb. CONCLUSION: In this model, guide wires with J curves 3 mm or less in diameter are a t risk for entrapment by Vena Tech filters.

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Journal of Vascular and Interventional Radiology

January-February 1995

45

4:30 PM

Long-term Follow-up of Patients with IVC Filters by Using Biplanar Inferior Cavography H.J. Jaeger, MD, Dortmund, Germany K.D. Mathiaq MD * U. Kempkes PURPOSE: Evaluation of the long-term complication rate for IVC filters with use of biplanar inferior vena cavography for follow-up. MATERIALS AND METHODS: In 55 consecutive patients, IVC filters were implanted over a 5-year period. Follow-up was obtained in 19 of these patients by means of biplanar inferior vena cavography. The mean follow-up time was 30 months (range; 6 months to 5 years). RESULTS: In the 19 patients in whom follow-up was obtained, the following filters were implanted: 10 Bird's Nest filters, four LGM filters, three Giinther basket filters, and two Giinther Tulip filters. Complete occlusion of the IVC was demonstrated in four patients (21%) and IVC thrombosis with partial occlusion of the IVC in two patients (11%).None of these patients had IVC thrombosis at the time of insertion. Perforation of the IVC wall was observed with nine filters of 15, excluding the four cases of caval occlusion (60%).In addition, two Bird's Nest filters demonstrated mechanical breakage and two LGM filters showed incomplete opening. Only one inferior vena cavogram was completely unremarkable except for the presence of the N C filter. CONCLUSION: Biplanar inferior vena cavography used for long-term follow-up of IVC filters will demonstrate a high incidence of complications. 46

4:45

PM

Retrievable IVC Filter: A New Design for Extended Implantation-In Vitro and in Vivo Evaluation J. Krysl, MD, S t Louis, MO T.M. Vesely, MD M.E. Hicks, MD PURPOSE: To evaluate a new retrievable IVC filter with in vitro and in vivo studies. MATERIALS AND METHODS: Eight filters were placed percutaneously through the femoral vein into the IVC in eight pigs. All pigs were killed after 30 days, four with the filters in situ and four following transvenous removal of the filter via concurrent jugular and femoral routes. Histologic evaluation, including scanning electron microscopy of the IVC wall and filter struts, was performed to assess for intimal hyperplasia. In addition, in vitro clot capture efficiency studies using both laminar and pulsed flow techniques as well as flow disturbance studies were performed.

RESULTS: All filters were successfully deployed in the infrarenal IVC. Transvenous extraction of the filter was successful in all four of the pigs in which it was attempted. After 30 days, intimal hyperplasia was present in the IVC at all the filter attachment sites but did not compromise filter retrieval. In vitro testing demonstrated clot capture capability and flow disturbance characteristics similar to those of available IVC filters. CONCLUSION: In the presence of intimal hyperplasia this filter demonstrates easy retrievability and in vitro performance similar to that of currently available filters. Role of Anticoagulation in a Tethered Temporary Vena Caval Filter in a Swine Model B.G. Johnson, BS, Baltimore, MD R.L. Reichle, MD A.C. Venbrux, MD M.A. Samphilipo, Jr, BS C.A. Magee, BS J.H. Anderson, PhD, et a1 PURPOSE: To evaluate the role of anticoagulation after deployment of the Tempofilter caval filter and to study the histopathologic effects of the filter on the caval wall of a swine animal model. This temporary filter is in clinical use in Europe. MATERIALS AND METHODS: Anticoagulation is initiated when possible. The filter was fluoroscopically placed in the infrarenal IVC through an external jugular cutdown in seven swine. The tethering catheter, attached to the filter, was secured subcutaneously at the cutdown site, where it can later be explanted. Intravenous heparin was administered during deployment, and oral Coumadin therapy was then initiated. In addition, concomitant Enoxaparin was given in two animals for 5 days. Studies include pre- and posttreatment cavography, pulmonary arteriography, and gross and histologic examination of the cava after death. RESULTS: In animals receiving Coumadin alone, thrombus was noted on the Tempofilter or caval wall in four or five. Concomitant subcutaneous Enoxaparin significantly reduced thrombus formation. Pulmonary arteriography showed no significant pulmonary embolus. Filter migration (3-12 cm) was observed in all animals. CONCLUSION: Coumadin therapy alone does not consistently prevent thrombus formation on the Tempofilter or caval wall. However, in swine receiving concomitant subcutaneous Enoxaparin, thrombus formation was significantly decreased.

1995 SCVIR Meeting Abstracts

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Volume 6 Number 1

New IVC Filter Retrievable Even after Neointimal Formation T. Irie, MD, Saitama, Japan S . Kusano, MD PURPOSE: To develop a new IVC retrievable filter. MATERIALS AND METHODS: Eight new filters were placed percutaneously in the infrarenal IVC of eight dogs. Four weeks after placement, percutaneous retrieval of the filter was attempted. Three dogs were killed immediately after retrieval. In the other five dogs, follow-up cavography was done 4-14 weeks after retrieval to assess the IVC for delayed stenosis, and autopsy was performed. RESULTS: The filters were placed and retrieved successfully in all eight dogs. No filter showed migration, caval penetration, or tilting. The IVCs were patent both before and immediately after retrieval in all eight dogs. Delayed stenosis of the IVCs was not seen in any of the five dogs that were followed UP. CONCLUSION: This new IVC filter can be easily placed and safely retrieved percutaneously even after neointimal formation.

Monday, March 27 Ballroom Scientific Session 9 Stent-Grafts MODERATOR:

Joseph Bonn, MD, Philadelphia, PA

Initial Experience with Combined SurgicalInterventional Procedures Performed in the Interventional Suite B.T. Katzen, MD, Miami, FL G.J. Becker, MD J.F. Benenati, MD G. Zemel, MD O.A. Puente, MD J. Aluarez, Jr, MD, et a1 PURPOSE: To determine the feasibility of performing vascular interventions that require surgical access in the interventional suite, rather than the operating room. MATERIALS AND METHODS: Requirements to obtain a necessary aseptic environment were reviewed using AORN, Joint commission, and Florida state regulatory guidelines. Rather than create an operating room with angiographic equipment, we attempted to modify the interventional environment to make it suitable for performing the types of procedures requiring surgical access by femoral artery

cutdown, but also adequate for more extensive surgery on an emergency basis. Issues such as air handling, scrub location, surface substances (floors and ceilings), controlled flow of personnel, handling of blood products, anesthesia, and training and integration of staff were carefully studied by a multidisciplinary task force of interventionalists, vascular surgeons, cardiologists, anesthesiologists, and administrative representatives from infection control, operating room, risk management, and interventional services. Preparations for adverse events were made and rehearsed. This resulted in an integrated team of interventionalists and surgeons working with support teams from the operating room and interventional services, with movement of support equipment such as "cell-saver", anesthesia equipment, and surgical instruments. RESULTS: Eight patients underwent placement of endografts via cutdown in the interventional suite (seven femoral, one axillary). In one patient, rupture of the iliac artery by the delivery device required immediate conversion to iliofemoral bypass, which was done successfully. Postprocedural surveys showed unanimous acceptance of this approach, and postprocedural infection rates fall within accepted standards. CONCLUSION: An aseptic environment suitable for endoluminal vascular grafting using surgical access can be created in a so~histicatedinterventional suite. High levels of multidisciplinary cooperation are necessary for implementation. Transluminal Stent-Graft Management of Descending Thoracic Aortic Aneurysms M.D. Dake, MD, Stanford, CA C.P. Semba, MD D.C. Miller, MD R.S. Mitchell, MD R.P. Liddell, MD PURPOSE: To evaluate the safety and effectiveness of a transluminally placed stent-graft device for the treatment of thoracic aortic aneurysms. MATERIALS AND METHODS: Custom-fabricated, self-expanding stent-grafts composed of a stainless steel endoskeleton consisting of Z-shaped elements and woven Dacron graft material were implanted in 36 patients with thoracic aortic aneurysms (25 true and 11 false aneurysms). A variety of etiologies included atherosclerosis, dissection, trauma, and postoperative and mycotic conditions. Follow-up CT and angiography were performed in all patients. RESULTS: Deployment of the prosthesis was technically successful in all cases. Nine ~ a t i e n t srequired multiple stent-grafts to cover the aneurysm completely. Complete thrombosis of the aneurysm

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Journal of Vascular and Interventional Radiology

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was achieved in 33 patients. One patient died within 30 days of the procedure. Paraplegia occurred in two patients. There were no instances of stroke, infection, or distal embolization. The mean follow-up interval is 9.8 months (range, 2-30 months). CONCLUSION: In our limited early clinical experience, transluminally placed stent-grafts appear to represent a feasible alternative to standard surgical procedures for management of highly selected patients with descending thoracic aortic aneurysms.

51 2:15~~ Initial Clinical Experience with Endoluminal Vascular Grafting G.J. Becker, MD, Miami, FL B.T. Katzen, MD J.F. Benenati, MD G. Zernel, MD J . Aluarez, Jr, MD O.A. Puente, MD PURPOSE: To summarize our experience with treating aneurysms and traumatic vascular lesions with endoluminal grafts. MATERIALS AND METHODS: Endograft placements were attempted in 11 patients for the following: abdominal aortic aneurysm (n = 5), with Dacron tube grafts affixed to proximal and distal metallic anchor hooks; thoracic aortic aneurysm (n = 21, with Dacron-covered Z stents; iliac artery aneurysm, with 4-mm polytetrafluoroethylene (PTFEIcovered Palmaz stents (n = 1)and 8-mm PTFE sewn to leading and trailing Palmaz stents (n = 1); and iliac artery pseudoaneurysm (n = 1)and iatrogenic subclavian artery trauma (n = I), with silicone-covered Palmaz stents. Ten procedures required surgical cutdown (common femoral, n = 9; axillary, n = 1).Ten procedures were performed in an interventional suite outfitted as an operating room. Follow-up included one or more of the following at specified intervals: CT, angiography, duplex US. RESULTS: Endograft deployment was achieved in 10 of 11 patients. One of these 10 had a persistent leak at the inferior end a t 6-month follow-up; the other nine lesions were successfully excluded. Adjunctive embolization with coils was required in two, (one iliac artery aneurysm and one iliac pseudoaneurysm). One failed deployment of an 8-mm PTFE graft in the iliac artery resulted from lack of an adequate delivery system. In 1-month to 3-year follow-up, only the failed deployment required surgical treatment of the aneurysm, although the patient with the inferior leak is scheduled for operative repair. There has been no perioperative mortality. Stroke due to atrial fibrillation occurred in a patient with an abdominal aortic aneurysm within 30 days

of repair. Other complications included one minor groin infection, two cases of prolonged fever without sepsis, and two sheath-related iliac artery injuries requiring repair (one stent and one bypass graft). CONCLUSION: Endoluminal vascular grafting is feasible and will certainly have an impact on the management of aneurysm and other disorders in the near future.

Stent-Graft Repair of Long-SegmentAortoiliac Occlusive Disease Coexisting with Common Femoral Artery Disease Precluding Routine Percutaneous Intervention J . Cynarnon, MD, Bronx, N Y M.L. Marin, MD C.W. Bakal, MD F.J. Veith, MD PURPOSE: Significant disease or occlusion of the common femoral artery (CFA) may preclude percutaneous therapy for aortoiliac occlusive disease. In addition, aortoiliac PTA may not reverse the ischemic symptoms when CFA disease exists. We described the use of endoluminal stent-grafts to treat multilevel aortoiliofemoral occlusive disease. MATERIALS AND METHODS: We have placed 23 stent-grafts for aortoiliac occlusive disease in patients with limb-threatening ischemia. In 13 patients the CFA was occluded ( n = 8) or severely diseased (n = 5), necessitating endoluminal bypass to the superficial femoral or popliteal artery (n = 61, or the deep femoral artery (n = 4), or necessitating patch angioplasty of the CFA ( n = 3). Stent-grafts were fabricated from 6-mm polytetrafluoroethylene and 30-mm Palmaz stents. The average graft length was 31 cm. RESULTS: All 13 grafts were placed successfully. Follow-up ranges from 1 to 18 months (mean, 8.5 months). Two patients have died of myocardial infarction (2 and 3 months after the procedure); three grafts have occluded during follow-up, resulting in a patency of 73%. CONCLUSION: Endoluminal stent-grafts can be useful in repairing severe aortoiliac disease where the CFA is involved, precluding routine percutaneous therapy, and thus avoiding an extraanatomic bypass or a major aortic bypass procedure.

1995 SCVIR Meeting Abstracts

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Volume 6 Number 1

Endovascular Technologies Endograft: Initial Results of a Multicenter Randomized Trial for Treatment of Abdominal Aortic Aneurysm B.T. Katzen, MD, Miami, FL G.J. Becker, MD J.F. Benenati, MD G. Zemel, MD O.A. Puente, MD Endovascular Technologies Investigators* PURPOSE: To report the initial results of a prospective randomized trial of a transluminally placed endograft for the treatment of abdominal aortic aneurysm. MATERIALS AND METHODS: A prospective randomized trial comparing endovascular therapy of abdominal aortic aneurysm with the conventional surgical approach is underway at 15 centers in the United States and is being conducted in two phases. Endovascular therapy is performed in an interventional suite or in the operating room, using a femoral artery cutdown. Procedures are performed by an integrated interventional and surgical staff. Patients must be candidates for conventional surgery to be entered into the trial. RESULTS: Initial results of the phase I trial (nonrandomized, 15 patients) demonstrated a conversion rate to standard surgery of 27%. More recently, phase I results, after modifications of the delivery device (12 patients) yielded a conversion rate of 8%. Complication rates and average hospital stay were considerably lower in the group treated by endovascular methods. CONCLUSION: Based on preliminary experience in this multicenter trial, endovascular treatment of abdominal aortic aneurysm appears to be a promising alternative to the conventional surgical approach.

Bifurcated Endovascular Graft for Repair of Abdominal Aortic Aneurysms T.A. Chuter, MD* E.C. Martin, MD, New York, N Y PURPOSE: To repair abdominal aortic aneurysms with a bifurcated endovascular graft. MATERIALS AND METHODS: Twenty-seven patients were treated with bilateral femoral cutdowns for access. The device comprises a thin-wall Dacron Y-graft attached to a large Gianturco stent and two 12-mm Gianturco stents at each trailing end. The device is constrained on a catheter with an outer diameter of 21 F. RESULTS: There were two deaths within 30 days (7%),but neither were procedure related. In two patients delivery was aborted and open repair undertaken. Small leaks were seen at the site of the stent in three patients, and these closed in two without

treatment. Initially, limb thrombosis was a common problem, which was managed with thrombectomy and stent placement. In the last 17 patients, bilateral Wallstents have been placed in the graft limbs routinely and no thrombosis has been seen. Eighteen patients are alive and well without further intervention. CONCLUSION: The endovascular graft has undergone modifications during this period. Endovascular graft placement with this bifurcated graft is now feasible, and the results are encouraging.

Monday, March 27 Room 305 Scientific Session 10 Angioplasty: New Investigations Richard D. Shlansky-Goldberg, MD, Philadelphia, PA MODERATOR:

Immunolocalization of Proliferating Smooth Muscle Cells in the Artery after Balloon Angioplasty A. Kwak, B S P.M. Consigny, PhD N.J. Vitali, B S PURPOSE: Experiments were performed to characterize the location of proliferating smooth muscle cells in the balloon-dilated artery to determine the most appropriate pattern of local antiproliferative drug delivery. MATERIALS AND METHODS: Balloon angioplasty was performed on the external iliac arteries in each of four rabbits. The arteries were removed 3 days later, frozen, sectioned, and immunostained with Ki-67, an antibody that identifies proliferating cells. The sections were then examined to determine patterns of smooth muscle proliferation within the arterial media. RESULTS: Of the 31 arterial cross sections examined, cell proliferation was circumferential in five (16%) and focal in 26 (84%). Of the 86 sites of proliferation examined within the 31 cross sections, proliferation was localized to the inner media in 30 (35%), and the outer media in four (5%),and was transmural at 52 (60%). The internal elastic lamina (IEL) appeared normal at 22 sites (26%)but appeared stretched or torn at 64 sites (74%). Proliferation was usually confined to the inner media at sites having no IEL injury (18 of 22; 82%) but was most often transmural where the IEL was stretched or torn (49 of 64; 77%).

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Journal of Vascular and Interventional Radiology

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CONCLUSION: These results suggest that angioplasty-induced cell proliferation can best be inhibited if an antiproliferative drug is delivered throughout the media.

vascular irradiation afterloading method is used with Ir-192 HDR, the method can be used with only low-grade somatic risk for the surrounding tissue.

Myointimal Hyperplasia: Long-term Results of a Pilot Study of Prophylactic Endovascular Radiation Therapy in Peripheral Vessels D.D. Liermann, MD, PhD, Frankfurt, Germany B. Schopohl, MD G. Strassmann, MD PURPOSE: Restenosis in peripheral vessels caused by intimal hyperplasia after stent implantation, PTA, atherectomy, or laser treatment ranged up to 40%. To avoid the hyperplastic reaction with restenoses, we treated our patients with prophylactic endovascular afterloading therapy after unsuccessful treatment with PTA alone and in cases of recurrent stenosis. MATERIALS AND METHODS: After treatment of occluded or stenotic lesions in peripheral vessels, we had more than 20 patients with up to four recurrent stenoses between 4 and 7 months due to intimal hyperplasia in the stented area. To minimize the reocclusion rate, we performed irradiation with a 12-Gy surface dose in one session, using the endovascular afterloading method with Ir-192 HDR following repeated PTA in the stented vessel segment. RESULTS: In 19 patients the treated vessel segments remained completely patent. The longest follow-up is 60 months in two cases; the mean followup is 32 months. In one case we had a complete occlusion in the origin of the superficial femoral artery caused by stenotic lesions above the stented and irradiated area 2 years after irradiation therapy, and this occlusion cannot be probed. This patient underwent femoropopliteal bypass. The histologic analyses of tissue 1-2 years after irradiation showed a thinner, more compact cellular layer of the myofibroblasts with less myxoid degeneration between the cells, compared with intimal hyperplasia and plaques in nonirradiated vessel segments. CONCLUSION: The follow-up showed a reasonable effect of endovascular radiation therapy. The histologic findings after irradiation were a diminished growth in the cellular population of the analyzed vessel wall compared with nonirradiated vessel wall segments in the same patient. These findings may be explained by a reduced migration and mitosis rate of myofibroblastic cells after irradiation. The method may be an interesting alternative to stent implantation alone. Even vessel segments like the Hunter channel will be patent for a long period. Because of the steep decay in the dose when the endo-

Inhibition of Intimal Thickening after Primary Balloon Injury in Rabbits by Oral B-Cyclodextrin Tetradecasulfate R.D. Shlansky-Goldberg, MD, Philadelphia, PA W.B. Bachinsky, MD M.A. Golden, MD E.S. Barnathan, MDX PURPOSE: We report the use of P-cyclodextrin tetradecasulfate (CDT), a nonanticoagulant heparin mimic, given orally and locally via a perforated balloon to reduce intimal thickening in a new, nonatherosclerotic injury model. MATERIALS AND METHODS: Twelve nonatherosclerotic New Zealand White rabbits underwent bilateral iliac artery denudation (twice a t 6 atm) with a 2.5-mm angioplasty balloon. Group 1 ( n = 5) underwent a combination of local treatment via a perforated balloon (ACS) to the right iliac artery only (50 mg1mL x 3 cm3 a t 4 atm) and oral CDT (2 mgl mL drinking water) for 14 days. Group 2 ( n = 2) received oral CDT and local delivery of saline, while a control group 3 ( n = 5) received local delivery of saline and no CDT. RESULTS: Intimal area and intimalmedia area ratios were reduced 39% ( P < .05) and 54% ( P < .001), respectively, in the nonlocally treated vessels in oral CDT-treated animals, compared with controls. The percentage of stenosis at 14 days was reduced from 47% to 33% in these vessels, as indicated with angiography (P = .19). There was no benefit of local treatment with CDT. CONCLUSION: Orally administered CDT reduces intimal thickening in this nonatherosclerotic primary injury model. Local therapy did not appear to add benefit.

Release of Extracellular-matrix--degrading Enzymes after Balloon Angioplasty G. Mucca, BS P.M. Consigny, PhD, Philadelphia, PA N.J. Vitali, B S PURPOSE: Experiments were performed to determine if angioplasty induces cells within the arterial wall to produce metalloproteinases that degrade extracellular matrix and thereby enable smooth muscle cells to migrate. MATERIALS AND METHODS: Balloon angioplasty was performed on one iliac artery in each of four normal and four atherosclerotic rabbits. The undi-

1995 SCVIR Meeting Abstracts 23 Volume 6 Number 1

lated and dilated arteries were removed 1-4 days after angioplasty and were placed in organ culture for 4 days. Samples of media "conditioned by each of the arteries were assayed for the presence of metalloproteinases by using gelatin-containing SDSpolyacrylamide gel electrophoresis (zymography) under nonreducing conditions. RESULTS: Electrophoresis revealed that all samples of media conditioned by dilated arteries contained major bands of gelatinolytic activity a t 70-75 kD and 105-110 kD, whereas all samples of media conditioned by undilated arteries contained gelatinolytic activity only a t 70-75 kD. Both regions of gelatinolytic activity were inhibited by treatment with EDTA (10 mmoVL) or 1,lO-phenanthrolene (2 mmoV L), indicating that these gelatinases are metalloproteinases. CONCLUSION: These results demonstrate that angioplasty induces cells within the arterial wall to release a 105-110-kD gelatinase. This metalloproteinase may participate in the matrix degradation that enables smooth muscle cells to migrate to the intima and thereby contribute to restenosis.

Polymer-coatedDrug-eluting Stents to Control Intimal Hyperplasia: Experimental Use in Dogs A. Gabelmann, MD, Freiburg, Germany E.K. Strecker, MD* H. Stricker, PhD I. Boos, MD J. Haberstroh, MD M.F. Langer III, MD PURPOSE: Restenosis after successful stent implantation in the peripheral arteries remains the major problem limiting the long-term efficacy of the treatment. The purpose of this study was to determine the feasibility and efficacy of polymer-coated stents for local drug delivery of antiproliferative agents to inhibit smooth muscle cell (SMC) proliferation. MATERIALS AND METHODS: We used knitted flexible tantalum stents coated with a biodegradable polymer as a vehicle for drug delivery. In 12 dogs the in vivo effect of local drug delivery of heparin ( n = 6) and dexamethasone ( n = 6) was studied. Stents were implanted unilaterally into the femoral artery. The contralateral side served as a control with a blank stent. All animals were followed up with interval angiography until they were killed a t 3, 6, 12, or 24 weeks after stent placement, with consecutive pathologic specimens for gross and microscopic evaluation. RESULTS: All stents, except one heparin stent, remained patent throughout follow-up. Preliminary results of pathologic specimens demonstrate a thin-

ner neointima within the first 12 weeks in the dexamethasone group than in the control or the heparin group. CONCLUSION: This study demonstrates that local delivery of a n antiproliferative substance like dexamethasone with a polymer-coated stent is a feasible method. Locally administered dexamethasone seems effective in reducing SMC proliferation during the initial phase of intimal hyperplasia formation.

Assessment of the Hemodynamic Result of PTA with a Doppler Guide Wire: Initial Experience H.J. Wagner, MD, Marburg, Germany M. Hoppe, MD K.J. Klose, MD, PhD PURPOSE: To assess the hemodynamic results of balloon dilation of atherosclerotic arterial obstructions with the use of a Doppler guide wire. MATERIALS AND METHODS: A 0.018-inch 12MHz Doppler guide wire was used to measure the pre-, intra-, and poststenotic maximum peak velocity (MPV) and average peak velocity (APV) in 10 consecutive patients (six men, four women; mean age, 68 years + 11). Measurements were undertaken before and after PTA. Balloon dilation was performed in seven stenoses and five occlusions of the lower limb arteries. The ratio between pre- and intrastenotic APV and between pre- and poststenotic APV was measured before and after balloon dilation. Results were correlated with the angiographic measurement of the diameter of stenoses before and after treatment. RESULTS: The pre-lintrastenotic APV ratio was the best predictor for the grade of residual stenosis following balloon dilation and correlated well with the angiographic measurements ( r = .8). Balloon dilation resulted in a significant increase in AFV behind the obstruction (mean, 12.5 c d s e c before vs 27.6 c d s e c after PTA; P < .05 by matched pairs test). The pre-lpoststenotic APV ratio also decreased significantly (3.7 before vs 1.0 after PTA, P < ,005). Hemodynamic results correlated with the angiographic findings. CONCLUSION: The use of a Doppler guide wire allows the direct intravascular evaluation of the hemodynamic result of balloon dilation of a n atherosclerotic obstruction.

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Journal of Vascular and Interventional Radiology

January-February 1995

Monday, March 27 Room 316 Scientific Session 11 TIPS Follow-Up MODERATOR:

Ernest J. Ring, MD, San Francisco, CA

Four-year Study of TIPS G. Zemel, MD, Miami, FL G.J. Becker, MD J.F. Benenati, MD B.T. Katzen, MD PURPOSE: To determine the safety, efficacy, and longevity of TIPS. M A T E R I M S AND METHODS: TIPS were created percutaneously in 120 patients by using metallic expandable stents. Shunts were expanded (8-12 mm in diameter) to establish a portosystemic gradient of 12 mm Hg. Tandem stent shunts were required in four patients. Variceal embolization was performed in emergent patients with persistent gastric venous filling following TIPS. One hundred follow-up shunt venograms were obtained a t 6-month intervals in 50 eligible patients. RESULTS: Functional shunts were created in all but one case with no suitable venous access. Rebleeding frequency was 6.7% (8 of 120). Recurrent hemorrhage was succesfully treated by percutaneous means. The 30-day mortality was 9.2% (11of 120). Shunt-related encephalopathy occurred in 24 patients (20%).Shunt malfunction was identified in 21 of 50 patients (42%) undergoing follow-up venography. CONCLUSION: Our results suggest than an effective percutaneoua portosystemic shunt can be created safely via a transjugular approach. Close shunt surveillance is required to maintain prolonged patency.

Evaluation of Predictors for Development of TIPS Stenoses M.D. Darcy, MD K.M. Sterling, MD, St. Louis, MO M.C. Idso, RN, B S N PURPOSE: To determine which clinical or morphologic features predict the development of stenoses within a TIPS. MATERIALS AND METHODS: Eighty-eight patients underwent TIPS placement. Forty-six with more than 3 months of follow-up were selected for study. This cohort consisted of 22 patients who developed stenoses and a control group of 24 patients

with normal shunts. All 46 were followed up routinely with Doppler US andlor venography. Data were acquired prospectively. Clinical, laboratory, hemodynamic, and shunt morphologic parameters were analyzed for differences between stenosis and control groups. RESULTS: Mean follow-up for the cohort was 12 months (range, 3-36 months). No demographic, clinical, or laboratory parameter predicted stenoses, although there was a trend for more stenoses in patients with alcoholic cirrhosis and in ~ a t i e n t swith normal creatinine levels. Patients with stenosis had slightly higher mean portal pressures than control subjects (35.8 vs 30.5 mm Hg) but had equivalent portosystemic gradients and percentages of decrease in portal pressure. Concerning the procedural aspects of TIPS, there was a trend for stenoses to occur more often with more needle passes and when larger needle systems were used. A significant correlation ( P = .006) existed between stenoses and biliary punctures visualized during TIPS placement. CONCLUSION: Development of stenoses is difficult to predict with most clinical or laboratory parameters. Obvious transgression of bile ducts does correlate with later stenoses.

Life-TableAnalysis of Patency and Rebleeding Rates in a TIPS Population Undergoing Follow-up Imaging C.R. Rees, MD, Dallas, TX R.L. Niblett, BS F.J. Rivera, MD S.P. Lee, MD N.G. Diamond, MD PURPOSE: To evaluate patency and rebleeding of TIPS with life-table analysis. MATERIALS AND METHODS: TIPS was performed in 140 patients with a history of variceal bleeding. Kaplan-Meier analysis was performed for patency and variceal rebleeding. Patency was determined with US, venography, and pathology. Rebleeding was considered significant if at least 1 unit of packed red blood cells was required. Follow-up was loo%, with most patients undergoing US a t 1 and 3 months, venography a t 6 months, and then US every 6 months, with percutaneous correction of significant stenoses or occlusions. RESULTS: The following results were obtained with Kaplan Meier analysis (SE
1995 SCVIR Meeting Abstracts

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Volume 6 Number 1

pitalization) patient deaths were associated with rebleeding episodes. CONCLUSION: The incidence of TIPS occlusions was relatively low and stabilized after approximately 12 months. TIPS was quite effective for the prevention of rebleeding as indicated with life-table analysis. Episodes of rebleeding were uncommonly fatal, with late death usually being due to other causes. We attribute these favorable results to aggressive surveillance with US and venography and percutaneous correction of lesions prior to the development of adverse events.

Comparison of TIPS Procedure and Sclerotherapy for Treatment of Bleeding Esophageal Varices: Preliminary Results from a Randomized Study E.J. Ring, MD, San Francisco, CA J.P. Cello, MD J.M. LaBerge, MD R.L. Gordon, MD R.K. Kerlan, Jr., MD M. Simor, R N PURPOSE: Initial experience with TIPS has mainly been limited to treatment of variceal bleeding unresponsive to endoscopic sclerotherapy. This study was undertaken to directly compare TIPS with sclerotherapy in a group of patients who are considered candidates for either procedure. MATERIALS AND METHODS: Thirty-four patients with endoscopically confirmed bleeding esophageal varices were randomly assigned treatment with TIPS or a therapeutic course of endoscopic sclerotherapy. The patients were then followed up (average, 1 year) to determine the comparative incidence of such factors as rebleeding, encephalopathy, liver failure, and death. RESULTS: Patients were matched as far as age, sex, and most measurements of severity of liver disease, except that in the TIPS group there was a significantly higher incidence of preexisting ascites. In the sclerotherapy group, ( n = 18) there were seven cases of rebleeding and three cases of crossover, compared with no cases of either rebleeding or crossover in the TIPS group ( n = 16). The 30-day mortality rates and the rates of encephalopathy were similar in the two groups. CONCLUSION: Initial results suggest that patients undergoing TIPS have a significantly lower incidence of rebleeding than patients treated with sclerotherapy, with no difference in mortality or encephalopathy rates.

65 5:OO PM Effect of TIPS on the Quality and Longevity of Life G.K. Nazarian, MD, Minneapolis, MN H. Ferral, MD H. Bjarnason, MD W.R. Castaneda-Zuniga, MD J.M. Rank, MD C.A. Anderson, et a1 PURPOSE: To determine the effect of TIPS on the quality and longevity of life. MATERIALS AND METHODS: The medical records of 53 patients who underwent TIPS placement over a 15-month period were reviewed. Complications, various laboratory values, and quality of life as assessed by the Karnofsky scale were compared before and after TIPS placement. Finally, the 1-year mortality for patients who underwent TIPS placement for variceal bleeding was compared with reported mortality rates for patients who did not undergo TIPS. RESULTS: There was a 29% incidence of new or worsened encephalopathy, an 11% incidence of severe complications (intraperitoneal hemorrhage, pulmonary edema), and a 5% procedure-related death rate following TIPS placement. A significant decrease in blood urea nitrogen and increase in albumin levels was observed. A significantly improved quality of life was demonstrated, and the mortality rate at 1 year following TIPS placement was favorable. CONCLUSION: TIPS placement has a relatively high risk of serious complications. However, the procedure appears to result in an improved quality of life with improvement in nutritional status and some improvement in renal function for Child class A and B patients with complicated portal hypertension, at least in the short term. 66 5:15 PM Outcome in 60 Consecutive Patients with TIPS: Hemodynamics and Assessment of Quality of Life D.J. Fillmore, MD, Salt Lake City, UT F. J. Miller, Jr, MD L.F. Fox, PA J.A. Disario, MD C.C. Tietze, MD PURPOSE: To analyze the mortality, frequency of reintervention and rebleeding, and functional status in patients undergoing TIPS placement. MATERIALS AND METHODS: Sixty consecutive patients who had undergone TIPS were prospectively followed up clinically and angiographically a t 6 weeks; 3, 6, and 9 months; 1year; and annually thereafter. The Karnovsky scale was used in survivors to assess functional status. RESULTS: The Child class was A in 11patients, B in 22, and C in 27. The indications for treatment

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were variceal bleeding in 49 and refractory ascites in 11. Follow-up averaged 7 months (range, 3-674 days). Mortality was 13% a t 30 days (8 of 60) and 30% a t 90 days (18 of 60). Sixteen of 18 deaths occurred in Child class C patients, six in patients treated for intractable ascites ( P = .01). Late deaths occurred in seven patients (mean, 326 days). Two patients received liver transplants (at 228 and 266 days). Rebleeding occurred in 12 patients, eight from varices, two from portal gastropathy, and two from sclerotherapy ulcers. Intractable ascites resolved in three of four survivors. Eighty-four followup portal evaluations were performed. Stenoses were identified in 18 patients and treated by means of repeated stent placement in 14 and angioplasty in four. The mean time to first reintervention was 179 days (7-225 days). The average Karnovsky score in survivors was 82 (range, 60-100). CONCLUSION: TIPS is effective, with a variceal rebleeding rate of 20%. Hemodynamic surveillance is necessary due to a restenosis rate of 30%. Longterm survivors have good performance status. Mortality was significantly higher in patients treated for intractable ascites.

Monday, March 27 Room 315 Scientific Session 12 Thrombectomy and Venous Thrombolysis MODERATOR:

Michael D. Dake, MD, Stanford, CA

Therapeutic Management of IVC Thrombosis with a Mechanical Thrombectomy Device: Evaluation in an Animal Model C.H. Pozza, MD, Minneapolis, MN J.J. Cervera-Ceballos, MD A.K. Sakinis, MD J.L. Titus, MD, PhD D. W. Hunter, MD K. Amplatz, MD PURPOSE: To assess the efficacy of a mechanical thrombectomy device in subacute IVC thrombosis. MATERIALS AND METHODS: The device consists of a rapidly rotating blade that is housed in a metal capsule mounted on a soft 8-F catheter. The capsule has three exit ports, one being much smaller than the others, resulting in lateral deflection and excellent steerability. In eight canines, a 20-mm balloon catheter was placed within the IVC and left inflated for 7-9 days, following which the balloon was de-

flated and a venogram obtained to confirm the extent of thrombosis. The device was activated and slowly advanced through the IVC thrombus until it had cleared. Pulmonary angiography as well as pulmonary artery pressure and blood gas measurements were obtained before and after the procedure. RESULTS: Blood flow was reestablished in all cases. On average, the arterial blood oxygenation saturation decreased by 6% and the main pulmonary artery pressure increased by 3.5 mm Hg. Histopathologic evaluation of the IVC showed no damage to the vessel wall with small residual adherent wall thrombi. Occlusion of small pulmonary arterioles with embolic fragments were seen. CONCLUSION: This device provides a rapid therapeutic option for IVC thrombectomy and warrants further clinical evaluation.

Thrombolysis as Primary Treatment of Heparin-induced Thrombotic Thrombocytopenia T.O. McNamara, MD, Los Angeles, CA R.A. Bornberger, MD PURPOSE: To demonstrate the effectiveness of percutaneous transluminal intraarterial thrombolysis to treat arterial occlusions due to heparin-induced thrombotic thrombocytopenia (HITT) and systemic infusion for venous occlusions due to HITT. MATERIALS AND METHODS: Three postsurgical, heparinized patients with distal trifurcation arterial occlusions and one with massive leg venous thrombosis were treated with thrombolysis. Urokinase was infused systemically to treat the venous thrombosis and was infused through the catheter to treat the arterial occlusions. Heparin was stopped. Antiplatelet agents were not used. RESULTS: All of the occlusions were cleared. The arterial infusions required 24-48 hours and the intravenous infusion, 48-72 hours. No instances of new clot formation were noted during the infusions, despite the absence of anticoagulation. No instances of bleeding were noted. CONCLUSION: HITT is an uncommon complication of heparin treatment that can cause death and limb loss. Heretofore, treatment has consisted of stopping heparin and beginning other anticoagulation, with inconsistent results. Our experience suggests that thrombolysis can be definitive treatment to clear the existing occlusion and protect against new clot formation while waiting for sodium warfarin anticoagulation to become effective. The hypercoagulable state may protect against bleeding in these postoperative patients, despite systemic activation of the fibrinolytic system.

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Volume 6 Number 1

Thrombolytic Therapy for Treatment of Chronic Iliac Vein Thrombosis C.P. Semba, MD, Stanford, CA G.K. Lee, BS M.D. Dake, MD S.T. Kee, MD U.R. Nyman, MD H. Chang, MD PURPOSE: Deep venous thrombosis of the iliac vein has traditionally been treated with anticoagulation therapy. In long-segment (> 10 cm) iliac vein occlusions, rarely does the vein fully recanalize with anticoagulation therapy alone. We report our experience in treating chronic iliac vein occlusions (> 4 weeks old) with thrombolytic therapy. MATERIALS AND METHODS: Between August 1992 and January 1994, 13 limbs (11patients; mean age, 47.0 years; range, 28-73 years) with symptomatic iliac vein occlusions secondary to chronic deep venous thrombosis were treated. Persistent leg edema and pain (mean, 367 days; range, 28-1,095 days) were present in all cases. Via right internal jugular, femoral, or popliteal venous access, the iliac vein occlusions were successfully crossed with a guide wire, and all patients underwent thrombolytic therapy with catheter-directed urokinase infusions (average dose, 1.7 million units). Following lytic therapy, further interventions of balloon angioplasty and stent placement were performed if there was sufficient venous inflow from the infrainguinal deep veins. RESULTS: Thrombolysis was complete in 15% (two of 13) and partial in 77% (10 of 131, with no lysis in 7% (one of 13). Further interventions included placement of Wallstents ( n = 31, Palmaz stents ( n = 41, or both ( n = 2). No further interventions were performed in four limbs. The technical and clinical success rate was 85% (11of 13). CONCLUSION: Thrombolysis with adjunctive stent placement may be an acceptable alternative to anticoagulation in treating symptomatic chronic iliac vein occlusions.

Assessment of Venous Valvular Damage after Retrograde Passage of a Catheter-Guide Wire Infusion System J. W. Jaffe, MD*, Allentown, PA T.N. York, DO T. Matulewicz, MD PURPOSE: To determine whether retrograde passage of a coaxial infusion system (Mewissen-Katzen catheter and guide wire) into extremity veins with valves causes damage. MATERIALS AND METHODS: Retrograde common femoral vein puncture and passage of a n infusion

wirelcatheter system through the superficial femoral and popliteal vein was performed in one leg each of three anesthetized swine. Heparinized saline was then infused via catheter and wire for approximately 8 hours. The swine were then killed, and the femoropopliteal veins were removed from both legs of each pig and examined by a pathologist. The noncatheterized leg veins served as a control in each animal. RESULTS: There was no evidence of endothelial damage to the valves of two swine. In the third, there was minimal valvular damage, but this may have resulted from leg movement during catheter passage in this animal. CONCLUSION: In two swine retrograde passage of a catheter guide wire system for infusioncaused no damage to venous vascular cusps. In one there was minimal damage, probably due to movement during catheter passage. I t is possible that these results could be extrapolated, and retrograde catheter passage for venous thrombolysis may be safe in humans. 71 500 PM Catheter-directedThrombolysis of Iliofemoral Venous Thrombosis: University of Minnesota Experience H. Bjarnason, MD, Minneapolis, MN D.A. Asinger, B A B.A. Praus H. Ferral, MD G.K. Nazarian, MD T.V. Myers, MD, et a1 PURPOSE: We present our experience in treating iliofemoral venous thrombosis (IFT) using catheterdirected thrombolysis. MATERIALS AND METHODS: Forty-three patients with IFT have been treated (45 treatments) with use of catheter-directed thrombolysis. Urokinase was used in all cases. The drug was delivered by a coaxial infusion system into the clot, and foot vein infusion with concomitant pneumatic compression devices was used in many instances. We have reviewed 29 cases, but results from all of the treatments will be presented. Heparin was given concomitantly. RESULTS: Of the 29 cases reviewed so far, treatments were successful in 22 (76%). The average symptom length before treatment was 10.6 days (< 7 days in 14, 7-30 days in 10, > 30 days in five). The average treatment time was 2.9 days (range, 15 days) and 10,000,000 IU of urokinase was used on average (range, 1,000,000-20,000,000 IU). No serious complications were observed. The underlying pathology was revealed in many of the cases. Metal stents were placed in 11, and six were treated with angioplasty alone.

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CONCLUSION: Catheter-directed thrombolysis is a safe and effective treatment for acute iliofemoral venous thrombosis. The age of the thrombus is the most important prognostic factor. Treatment of Symptomatic Deep Venous Thrombosis in the Lower Extremity with Retrograde Catheter Placement and Urokinase Infusion J. W. Jaffe, MD*, Allentown, PA J.A. Newcomb, MD J.J. Goodreau, MD PURPOSE: Four-year experience with catheter-directed thrombolysis of iliofemoral deep venous thrombosis (DVT) via direct passage of the catheter into the affected veins. MATERIALS AND METHODS: Nineteen patients (mean duration of symptoms, 15 days) with phlegmasia dolens and documented iliofemoral thrombosis were treated. In 17 patients, a contralateral femoral approach and retrograde catheter passage were used. In all cases the infusion catheter or guide wire was advanced to the popliteal vein and a bolus1 infusion of urokinase used (mean dose, 7.2 million U). RESULTS: Eighteen patients demonstrated greater than 50% lysis and significant resolution of symptoms, with decreased pain and swelling, and improvement in limb status. One patient showed minimal lysis. One pulmonary embolus occurred, and no bleeding complication was encountered. At a mean follow-up of 12.5 months, three patients have manifested class I venous insufficiency; the remaining are asymptomatic. CONCLUSION: Catheter-directed thrombolytic therapy with retrograde catheter passage into lower extremity veins for symptomatic relief of phlegmasia dolens has a high initial success rate with minimal complications. This technique holds the promise of decreasing the rate and severity of postphlebitic syndrome; however, long-term follow-up over many years is needed, as well as comparison with other treatment modalities for symptomatic DVT.

Monday, March 27 Room 304 Scientific Session 13 Angiographic Technique MODERATOR:

Tony P. Smith, MD, Durham, NC

Lateralization of Ventilation Perfusion Imaging: Correlation with Pulmonary Angiography T.P. Smith, MD, Durham, NC E.R. Hudson, MD P.V. Suhocki, MD C.S. Payne, MD G.E. Newman, MD V. G. McDermott, MD PURPOSE: To determine if lateralization in ventilation-perfusion (VIQ) scanning can be reliably used for guidance of pulmonary angiography for pulmonary embolus. MATERIALS AND METHODS: Two hundred pulmonary angiograms were prospectively reviewed prior to pulmonary angiography to determine the lung most suspicious for pulmonary embolus based on areas of decreased radiotracer activity and mismatching on the VIQ images. Angiography was then performed in standard fashion, beginning with the most suspicious lung. RESULTS: Of 200 scans, 68 did not lateralize (R = L) and there were 16 patients (24%) with pulmonary embolus seen at angiography. One hundred thirty-two patients did have VIQ lateralization, and 44 of these patients had angiographic evidence of acute pulmonary embolus. In all cases the diagnosis was made by injecting the lung of most interest. No patient required angiography of the other lung for diagnosis. CONCLUSION: Pulmonary embolus can be diagnosed with high confidence by means of angiography of the most suspicious lung based on VIQ scanning. This has significant clinical applications in selected cases when angiography may need to be limited by fluid, time, and contrast material. It also may have implications for future imaging of pulmonary embolus.

Periprocedural Complications of Pulmonary Arteriography with Low-osmolar Contrast Material R.F. Oser, MD, St Louis, MO D.A. Zuckerman, MD K.M. Sterling, MD PURPOSE: To identify potential safety benefits from the use of low-osmolar contrast material

1995 SCVIR Meeting Abstracts 29 Volume 6 Number 1

(LOCM) in patients undergoing pulmonary arteriography (PA). MATERIALS AND METHODS: Results in 491 patients who underwent PA with LOCM were retrospectively reviewed. Immediate periprocedural complications were recorded, as were complications occurring within 48 hours of the procedure. Pulmonary artery pressure changes following contrast material injection were noted. Results were compared with pooled historical data from previous series in which LOCM was not used. RESULTS: To date, procedural details and immediate complications have been reviewed in 281 patients. Two major complications occurred (0.7%), including complete heart block and myocardial infarction in one patient and severe bradycardia and hypotension in another. Minor complications occurred in five patients. Twelve patients had significant intraprocedural arrhythmias; 11resolved spontaneously. No major complications occurred in patients with moderate or severe pulmonary hypertension ( n = 501, and no deaths occurred. Pre- and postinjection pressures were recorded in 125 patients. Of these, 31 (25%)had an increase in systolic pressure of 5-10 mm Hg and 16 (13%)had an increase of more than 10 mm Hg after injection of LOCM. The complication rates are lower than those reported from prior series. CONCLUSION: The use of LOCM can enhance the safety margin in PA. Patients with pulmonary hypertension have no apparent increased morbidity.

Role of Cyclic Adenosine Monophosphate in Contrast Medium Renal Artery Vasoconstriction P. Drescher, MD, Milwaukee, WI F. Pereira, DVM J.M. Knes, B S P.O. Madsen, MD PhD PURPOSE: To elucidate vasomotor mechanisms of radiographic contrast medium (RCM) vasoconstriction associated with acute renal failure. The intracellular mechanisms for RCM vasoconstriction remain unclear. Cyclic adenosine monophosphate (CAMP)plays a central role for vascular smooth muscle relaxation. We investigated its role in RCM vasorelaxation by blocking its degradation through phosphodiesterase (PDE) inhibitors and by directly stimulating it with forskolin. MATERIALS AND METHODS: Control isometric contractions in isolated rabbit renal arteries were obtained with KC1 (125 meq/L), and then with various concentrations of diatrizoate meglumine-diatrizoate sodium. The tissue was incubated with in-

creasing concentrations of the nonselective PDE inhibitors papaverine, theophylline, and forskolin. RESULTS: RCM elicited contractions in 24.5% of the control. Papaverine (1mmol), theophylline (5 mmol), and forskolin (50 pmol) reduced RCM contractions by 84.5%, 87.8%, and 92.3%, respectively. CONCLUSION: This study demonstrates that cAMP plays a crucial role in renal artery smooth muscle contraction. PDE inhibitors and cAMP stimulators are potential candidates in preventing RCM vasoconstriction and subsequent renal failure.

Evaluation of Reimplanted Renal Arteries after Aortic Bifemoral Graft or Renal Artery Bypass with CO, Angiography R.S. Young, MD, Gainesuille, FL I.F. Hawkins, Jr, MD* H.R. Smouse, MD S.R. Kerns, MD R.P. Booth, MD J.G. Caridi, MD PURPOSE: To determine the safety and efficacy of evaluating reimplanted renal arteries with CO, DSA in the perioperative period. Evaluation of the technical success of the revascularization is necessary, as early postoperative graft failure is reportedly 5%-11%, often resulting in loss of the kidney. Since these kidneys are ischemic during surgery, they are at increased risk with iodinated contrast material. MATERIALS AND METHODS: Thirty patients were evaluated perioperatively, before discharge, with use of CO, as a contrast agent. Small catheters (3 and 4 F) were used to minimize the morbidity of the procedure. The majority of procedures were performed with an automated CO, injector. Hand injection was performed in selected cases. Creatinine values were evaluated before and after the procedure. RESULTS: In all 25 examinations performed with CO, DSA and small catheters, the studies were technically successful. The anastomosed main renal artery and second- and third-order vessels were reliably imaged. No significant change in the creatinine values was noted after the procedure. No hematomas or other angiographic complications occurred. CONCLUSION: CO, DSA angiography, with the use of small catheters, is a viable and accurate means to evaluate reimplanted arteries without significant risk of renal dysfunction or patient morbidity.

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Journal of Vascular and Interventional Radiology

January-February 1995

CO, DSA in Renal Transplant Patients I.F. Hawkins, Jr, MD*, Gainesuille, FL R.S. Young, MD H.R. Smouse, MD S.R. Kerns, MD R.P. Booth, MD J.G. Caridi, MD PURPOSE: To evaluate the efficacy and safety of CO, DSA for the angiographic evaluation of renal transplant recipients. Our previous animal experience suggested that large volumes of the buoyant CO, injected in anteriorly positioned organs may cause a "vapor lock" phenomenon and transient ischemia. MATERIALS AND METHODS: Fifteen renal transplant recipients were examined with use of 3- and 4-F catheters. Serum creatinine levels were measured before CO, injection, 24 hours after injection, and during a follow-up clinic visit. Multiple injections (10-50 musec) were made into the iliac artery with a hand syringe or a dedicated injector. RESULTS: The main renal arteries and third- to fifth-order branches were imaged in all the studies. In over half of the cases, a small amount of iodinated contrast material (less than 10 mL) was used to verify the diagnosis. In two cases, the correct diagnosis was made only with CO,. The average creatinine values were 1.78 mg/dL before CO, injection, 1.96 mg/dL 1 day later, and 1.77 mgIdL at the next clinic visit. CONCLUSION: No procedural complications occurred. The kidney was reliably imaged with CO, DSA without significant degradation of renal function. To avoid possible ischemia, 5 minutes should lapse between injections to allow trapped CO, to dissolve.

New Angiographic Technique That Uses a High kVp, Low mA Electron Gun Radiographic Unit J.F. Cardella, MD, Hershey, PA J.D. Barr, MD T. Brinker, MD K.D. Hopper, MD A.B. Kreiss, RT(R), RCVT P.S. Fox, MD PURPOSE: Current DSA requires patient motionlessness and substantial postacquisition computer manipulation of digital data. This phantom and animal study was performed to test the feasibility of obtaining DSA-like angiograms directly (ie, without any postacquisition processing) on a prototype highkVp, low-mA, micro-focal-spot, electron gun unit sited at our institution by FDA exemption to study broken cardiac valve struts. MATERIALS AND METHODS: Phantom vessels 120 mm in diameter were filled with Hypaque 30%,

Hypaque 60%, Hypaque 76%, and gadolinium in a 20-cm water bath and were imaged at 120-170 kVp (0.2-0.7 mA) using direct magnifications of 3 x , 5 x , and 7x. Phantom obliquities of 0°, 30°, and 60" relative to horizontal were tested. After phantom testing, selective and nonselective catheter angiography was performed in two sheep, again with use of multiple contrast agents, radiographic techniques, magnifications, and projections. The sheep study was done to mimic pulsatile blood flow, contrast medium dilution, respiratory motion, and overlying body tissues. Phantom and animal images were reviewed blindly by a panel of three radiologists with regard to vessel edge sharpness, vessel conspicuity, and elimination of overlying soft tissues (sheep). RESULTS: All phantom vessels were seen with all four contrast agents; conspicuity and edge sharpness of the 1- and 2-mm vessels were reduced with Hypaque 30% and gadolinium. The conspicuity and edge sharpness of the larger vessels a t all contrast medium strengths and of the 1- and 2-mm vessels with Hypaque 60% and 76% were rated as very good to excellent by the panel. In the sheep study, overlying tissues were successfully eliminated, leaving only the contrast-filled vessels to be interpreted. The fluoroscopic mode of the feinfocus unit is not as good as that of a high-end portable C-arm (OEC Diasonics) but was suitable for catheter delivery to target vessels in 65-70-kg sheep. CONCLUSION: This pilot phantom and animal study showed that DSA-like angiograms can be obtained directly by using high-kVp to eliminate unwanted bones and soft tissues, and that conventional commercially available iodinated contrast agents can be seen at these high-kVp settings. The direct magnification capability without image blurring or loss of edge sharpness is another attractive feature of the feinfocus unit. Radiographically subtracted angiography, if successfully developed, will simplify acquisition and eliminate the complex postacquisition computer processing currently used.

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Volume 6 Number 1

Tuesday, March 28 Room 315 Scientific Session 14 Peripheral Vascular Stents MODERATOR:

Gary J. Becker, MD, Miami, FL

Comparison of Conventional Angioplasty and Angioplasty with the Palmaz Stent in the Treatment of Abdominal Aortic Stenoses from the STAR Registry M.A. Westcott, MD, Philadelphia, PA J. Bonn, MD PURPOSE: To compare the safety and short-term efficacy of conventional angioplasty (PTA) versus angioplasty with the Palmaz stent for treatment of infrarenal aortic stenoses. MATERIALS AND METHODS: Review of the multiinstitutional STAR Registry identified 23 patients with infrarenal aortic stenoses treated by means of conventional PTA ( n = 12) or angioplasty with the Palmaz stent ( n = 11). Technical and initial clinical success and short-term clinical success were evaluated, with data reported as means 2 standard errors. RESULTS: The rate of technical success was 92% with PTA and 100% with stents. Nine of 12 PTA patients and nine of 11 stent patients improved a t least two clinical categories, but two PTA patients worsened. Treated stenoses decreased from 85% + 3% to 22% 2 6% after PTA, and from 83% 2 5% to 10% 2 3% after stent placement (not significant [NSI). The transstenotic pressure gradient declined from 58 mm Hg k 12 to 7 mm Hg + 3 after PTA, and from 67 mm Hg 2 13 to 2 mm Hg 2 1 after stent placement (NS). Five complications occurred after PTA (42%), with no complications in the stent group. Nine PTA patients were followed up (mean, 10 months), with two clinical regressions, and a n ankle-brachial index (ABI) of 1.03 k 0.08. Eight stent patients were followed up (mean, 2 months), with no clinical regressions and ABI of 0.94 0.04 (NS). CONCLUSION: Intravascular stents are safe and effective in the treatment of infrarenal aortic stenoses and may lead to fewer complications and improved initial and short-term clinical success compared with conventional angioplasty.

Reassessment of Long-term Patency after Successful Placement of a Wallstent in the Iliac Artery and Multivariate Analysis of Prognostic Factors M.R. Sapoual, MD, Paris, France A. Long, MD G. Chatellier, MD J.C. Gaux, MD A.C. Raynard, MD C. Rouani, MD PURPOSE: To prospectively study the long-term patency after iliac artery stent placement and to search for independent factors predictive of angiographic outcome. MATERIALS AND METHODS: Between October 1987 and December 1993, 101 consecutive iliac arteries in 95 patients (age, 52.4 years + 10.3) were treated with Wallstent implantation. Patients were prospectively followed up with repeated angiographic controls. Clinical and angiographic prognostic factors were systematically recorded. The actuarial method was used to analyze primary and secondary patency. Kaplan-Meier curves for the time to angiographic success (absence of reocclusion/ absence of intimal hyperplasia, > 50%) were compared by means of the Mantel Cox test. The Cox proportional hazard model was used to test the prognostic value of the set of factors recorded. RESULTS: Mean follow-up was 30.6 months (range, 0-78 months). At 4.5 years, primary patency was 59.5% and secondary patency was 80%. Multivariate analysis showed that the following factors were associated with a better angiographic outcome ( t is the relative hazard): patency of the superficial femoral artery, t = 4.21; hypertension, t = 0.27; diameter of the stent implanted t = 3.13; fewer than two stents implanted t = 2.63, right side, t = 2.14; and absence of tobacco consumption, t = 1.98. CONCLUSION: Reassessment of long-term angiographic patency achieved with the Wallstent in the iliac arteries demonstrates a 80% secondary patency a t 4.5 years. The six independent risk factors isolated here help to predict the angiographic outcome and to determine which patients should be selected for iliac artery stent placement.

Endovascular Revascularization of Diffusely Diseased and Chronically Occluded Iliac Arteries with Wallstents T.P. Murphy, MD, Providence, RI R.E. Lambiase, MD R.A. Haas, MD G.S. Dorfman, MD M.S. Webb, MD W.I. Carney, MD, et a1 PURPOSE: To assess outcome after treatment of hemodynamically significant stenoses or occlusions

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in the iliac arteries with percutaneous placement of Wallstents. MATERIALS AND METHODS: Ninety-four iliac limbs were treated in 66 patients. Indications included claudication in 49 limbs, threatened limb in 45, diffuse stenosis (> 3 cm length) in 44, chronic occlusion in 39, flow-limiting dissection in four, and failed angioplasty in seven. RESULTS: Technical success was achieved in 90% (85 of 94), with major complications in 8%, and one death after 30 days (1%).Ankle-brachial indexes improved from 0.51 ? 0.23 to 0.75 ? 0.23. Mean follow-up was 12 months ? 6. Cumulative primary patency was 74% a t 1year and 67% at 2 years. Secondary patency was 86% at 2 years (SE, 4%). No significant change in the mean ankle-brachial index was seen during follow-up. CONCLUSION: Technical success and complication rates are very favorable. Primary patency is limited in these patients with advanced disease, but excellent secondary patency rates can be achieved. 82 3:15~~ Placement of Palmaz Stents in the Iliac and Femoral Popliteal Arteries: Four-year FollowUP M. Henry, MD, Essey Les Nancy, France M. Amor, MD G. Etheuenot, MD I. Henry, MD M. Allaoui, MD E. Le Borgne, MD PURPOSE: To compare the respective long-term results in iliac and femoropopliteal arteries with Palmaz stents at 4-year follow-up. MATERIALS AND METHODS: Three hundred ten symptomatic patients (271 male, 39 female; mean age, 63 years ? 0.72) received 418 stents. Two hundred thirty stents were placed in 184 iliac arteries, and 188 in 126 femoropopliteal arteries. Eighty-one percent of the vessels were stenosed, and 19% were occluded. RESULTS: At 4-year follow-up, the overall true primary patency rate was 76%, and the secondary patency rate was 93%. The rates of true primary patency were as follows by site: 86% for the iliac arteries, 88% for the upper third of the superficial femoral arteries (SFAs), 67% for the midportions of the SFAs (P < .001), and 44% for the lowest portions of the SFAs and the popliteal arteries. For secondary patency, the respective rates by site were 94%, 96%, 97% (P < .01), and 82%. The primary patency rates were 85% for stenoses and 46% for occlusions (P < .001); the secondary patency rates, 95% and 87% (P < .05). The primary patency rates were 82% for lesions smaller than 3 cm (P < .01), 65% for larger lesions; 82% for single stents, and

66% for multiple stents (P < .05); the comparable secondary patency rates were 95%, 89%, 94%, and 90%, respectively. CONCLUSION: Iliac and femoropopliteal Palmaz stents are suitable for stenosed and occluded lesions in all locations. Long-term patencies of stents from the iliac arteries down to the middle third of the SFA are similar. The rate of secondary patency is a little lower in the bottom third of the SFAs and in popliteal arteries.

Two Years of Results of Palmaz Stent Placement in Superficial Femoral Arteries J. Pinot, PhD J. Pernes, PhD, Antony, France M. Auguste, PhD J. Langlois, PhD D. Houasse, PhD PURPOSE: To determine the immediate and 2-year effectiveness of Palmaz stents used in superficial femoral arteries (SFAS)after unsuccessful balloon angioplasty. MATERIALS AND METHODS: Among 136 patients treated with angioplasty for SFA lesions, Palmaz stents were used after poor results of balloon angioplasty, including residual stenosis or occlusion and dissection in 37 patients. Preangioplasty lesion classification (according to the standards of the SCVIR), corresponded to category 1 in seven patients (single short stenosis in four patients and 2-cm occlusion in three patients), category 2 in 15 patients (heavily calcified stenosis in nine and 5-cm occlusion in six), and category 3 in the remaining 15 patients. The mean diameter of the SFA lesion was 5.5 mm (range, 4.5-8 cm). Distal runoff was good in 30 patients and poor in seven. RESULTS: Forty-eight Palmaz stents were placed without technical difficulties in 37 SFAs. All cases showed angiographic restoration of patency and elimination of the dissection flap. One groin hematoma, one distal embolism, and one arteriovenous fistula were noticed. The mean follow-up was 22 months (range, 1-42 months), and 35 of 37 patients were monitored with Doppler US and intravenous DSA. The actuarial graph of patency by the KaplanMeier method shows primary patency rates of 72% and 62% at 1 and 2 years, respectively, and secondary patency rates of 80% and 69%. CONCLUSION: Palmaz stents are of value for improving the results of inadequate PTA in the SFA.

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The U.S. Food and Drug Administration Trial of the Wallstent: One-year Results E.C. Martin, MD*, New York, N Y The Wallstent Trialists PURPOSE: To assess the Wallstent in the iliac and femoral systems. MATERIALS AND METHODS: This study included 224 patients entered between 1991 and 1993; 139 had iliac and 90 had femoral stents. Seventy-seven percent had claudication. For the 164 stented sites in the iliac system the indications were chronic occlusion in 14, recent restenosis in eight, and an unsatisfactory angioplasty in 142 limbs. In the femoral system 91 limbs were stented for an unsatisfactory angioplasty. Sixty-three percent of the patients underwent follow-up angiography. RESULTS: In the iliac system the initial success was 96%, and the ankle-brachial index (ABI) rose from .64 to .86. On the Rutherford scale, 82% of cases were +2 or + 3 and 96% were + 1 or greater. At 6 months the primary patency was 90%, and at 1 year 78% (SE, 3.6%). The primary angiographic patency a t 6 months was 93%. In the femoral system the initial success was 99%, and the ABI rose from .69 to .96. On the Rutherford scale, 87% of cases were +2 or + 3 and 95% were + 1 or greater. At 6 months the primary clinical patency was 73% and a t 1year, 54% (SE, 5.6%). The primary angiographic patency at 6 months was 81%. CONCLUSION: The Wallstent has a satisfactory 1year patency in the iliac and femoral systems.

Tuesday, March 28 Room 304 Scientific Session 15 Embolotherapy: Peripheral MODERATOR:

Richard B. Towbin, MD, Pittsburgh,

PA

Venous Malformation Compartmental Pain Syndrome: Treatment with Percutaneous Sclerotherapy S.J. Lengle, MD, Sacramento, CA M. Stein, MD T.J. Rhodeman, MD D.P. Link, MD PURPOSE: The purpose of this study was to evaluate the effectiveness of percutaneous sclerotherapy to relieve exercise-induced compartmental pain as-

sociated with venous malformations of the lower extremities. MATERIALS AND METHODS: Six patients with venous malformations of the lower extremities were evaluated from August 1992 until the present. Symptoms ranged from total disability of the affected limb after mild exercise to moderate pain after strenuous exercise. The mean age was 27 years (range, 13-56 years). The mean follow-up was 8.8 months (range, 1-18 months). Patients were evaluated with duplex Doppler US, MR imaging, MR angiography, contrast venography, and arteriography. Treatment consisted of one to nine sessions of percutaneous sclerotherapy with absolute ethanol and/ or sotradecol in six patients under deep sedation (total, 24 sessions). Patients were followed up clinically, with MR imaging, and with US. RESULTS: Three patients showed dramatic improvement, with near total resolution of pain and limitation of motion. One patient had improvement from near total disability to moderate exercise tolerance. One patient gained moderate relief of pain allowing for increased exercise tolerance. Two patients remain unchanged and are continuing therapy. There was one minor and no major complications. CONCLUSION: Percutaneous sclerotherapy may result in dramatic relief in the compartmental pain associated with venous malformations. The clinical and imaging evaluation, percutaneous methods, and follow up of these patients will be described.

Pharmacologic Manipulation in the Safe Performance of Subselective Embolization of Peripheral Vascular Malformations from the Transfemoral Approach M.J. Hogan, MD, Cincinnati, OH N.D. Johnson, MD W.S. Ball, Jr, MD PURPOSE: Vascular malformations of the distal extremities were embolized safely from a transfemoral approach by combining pharmacologic manipulation with coaxial catheter systems in a pediatric population. MATERIALS AND METHODS: We reviewed the radiologic findings and outcome in 13 children in whom a distal peripheral vascular malformation was embolized through a transfemoral approach with pharmacologic manipulation (nitroglycerin, 0.5-1.0 pgkglmin, continuous infusion to prevent vasospasm; and heparin 50-100 mgkg every 3 hours during the procedure to prevent clotting) performed to reduce the risk of catheterization. The patients ranged in age from 13 to 33 years (mean, 18

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Journal of Vascular and Interventional Radiology

January-February 1995

years). Subselective embolization was performed through a coaxial system with polyvinyl alcohol, coils, alcohol. and silk thread. Outcome was assessed for complications related to the procedure and required follow-up therapy. RESULTS: A total of 24 procedures were performed in 13 patients with either angiomatous or arteriovenous malformations. All patients except one received a combination of nitroglycerin and heparin throughout the procedure. One major complication of spasm and thrombosis occurred in the procedure in which pharmacologic manipulation was not utilized. No other complications were encountered, other than a small groin hematoma. All arteriovenous malformations were treated successfully, with recurrence in six patients all treated with repeated embolizations. The remaining patients were improved or symptom free after follow-up of 6 months to 10 years. CONCLUSION: Transfemoral treatment of peripheral vascular malformations may be complicated by spasm and/or thrombosis, which limits a successful result. Both can be successfully prevented by the use of pharmacologic manipulation and coaxial catheter systems in children. 87 3:OO PM CO, DSA in Sclerotherapy of Hemangiomas J. W. Chung, MD, Seoul, Korea J.H. Park, MD H.S. Kang, MD K.M. Yeon, MD M. C. Han, MD PURPOSE: To investigate the usefulness of CO, DSA in direct puncture sclerotherapy of hemangiomas involving extremities. MATERIALS AND METHODS: Ten procedures of direct puncture sclerotherapy were performed in seven patients. After direct puncture of the hemangiomas, 30-50 mL of CO, was manually injected and digital subtraction angiograms were obtained. If draining veins were visualized, a tourniquet was applied a t the proximal site of hemangiomas to compress the draining veins. Thereafter, radiopaque embolic materials such as a 1:3 mixture of Lipiodol and absolute ethanol or ethanolamine oleate-lipiodol-Avitene (microfibrillar collagen hemostat) mixture were slowly injected under the fluoroscopic guidance. RESULTS: Rapid injection of a large amount of CO, enabled the visualization of wide areas of hemangiomas. Draining veins were reliably demonstrated in nine procedures and pulmonary embolization of embolic materials was effectively controlled by proximal tourniquet application. Because of the radiolucent nature of CO, retained in hemangiomas, we could clearly identify the distribution of radiopaque

embolic materials under fluoroscopy. Retained CO, also could be used as a guide for additional multiple puncture of hemangiomas. There were no systemic symptoms or complications related to CO, DSA. CONCLUSION: CO, DSA is a convenient, safe, and useful angiographic technique in direct puncture sclerotherapy of hemangiomas involving extremities. 88 3 : 1 5 ~ ~ Combined Treatment of Peripheral Arteriovenous Malformations with Interventional Radiology and Surgery P. Falappa, MD, Rome, Italy F. Stillo, MD P. Puddu, MD F. La Schena, MD P. Tempesta, MD S. Camilli, MD, et a1 PURPOSE: The purpose of this presentation is to evaluate the combination of interventional radiology and surgery in the treatment of peripheral arteriovenous malformations (AVMS).. MATERIALS AND METHODS: Nine patients affected by peripheral AVMs (two thoracic wall, three face, three leg, one pelvic) were treated with selective transcatheter embolization and subsequent surgical resection of the lesions. The AVMs were diagnosed by means of color Doppler US, CT and/or MR imaging, and arteriography. Two sessions of embolization were performed before surgical resection in five cases and one session was performed in four; in one case a postsurgical embolization has been performed. The following embolizing agents were used: polyvinyl alcohol, Hystoacril + Lipiodol, coils, Gelfoam, and ethanol 95% (direct injection). RESULTS: Tne follow-up (8-30 months) shows attenuation of subjective clinical symptoms and functional improvement in all patients, without complete restitutio ad integrum in the most complex lesions. Until now, after surgical resection a second treatment has never been requested. We did not register any major complication. CONCLUSION: The results show that the combination of interventional radiology and surgery in the treatment of AVMs enhances therapeutic effect and is more safe than either technique alone.

Treatment of Large Venous Malformations of the Neck and Mediastinum in Children E.A. Lebowitz, MD, Boston, M A P.E. Burrows, MD F.A. Hoffer, MD PURPOSE: To present techniques for sclerosis of large venous malformations with unobstructed venous drainage. MATERIALS AND METHODS: Four children with extensive venous malformations of the neck and me-

1995 SCVIR Meeting Abstracts 35 Volume 6 Number 1

diastinum had large varices of the external jugular or inferior thyroid veins. Injected ethanol escaped when prolonged local compression was discontinued. Tissue adhesive ( n = 1)and platinum coils ( n = 3) were used to occlude the venous outlets or pack the varix, prior to the reinjection of ethanol. Other portions of the malformation were injected during the same procedure. RESULTS: In all patients, at fluoroscopy, opacified ethanol was seen to persist within the varix when injected after placement of the coils or tissue adhesive. The injected lesions became firm within 24 hours, indicating thrombosis. On clinical follow-up, two lesions regressed completely, with no further filling on Valsalva maneuver. In a third patient with a more diffuse lesion, the injected area decreased in size. The fourth patient had thrombosis of the lesion on MR images with clinical resolution and improvement in airway obstruction. CONCLUSION: Extensive venous malformations of the neck and mediastinum may contain large varices of conducting veins. The placement of platinum coils to obstruct venous outflow is helpful in achieving effective ethanol sclerosis. 90 3:45 PM Anomalous Vascular Communications of the Head and Neck That Mimic Congenital Heart Disease: Management with Coil Embolization D.C. Redd, MD, Philadelphia, PA M.C. Soulen, MD K.E. Fellows, Jr, MD PURPOSE: We describe four children presenting with murmurs in whom extracardiac abnormal vascular communications were diagnosed angiographically and managed with transcatheter therapy. MATERIALS AND METHODS: Four children, 4 weeks to 3 years old, had murmurs and abnormal chest films suggestive of congenital heart disease. US in two, and cardiac catheterization in all four, showed cervical or thoracic systemic arteriovenous or systemic-to-pulmonary fistulas. Selective catheterization and coil embolization were performed in all. RESULTS: Fistulas treated were between the distal left internal mammary artery and a hypoplastic left pulmonary artery; the right supreme intercostal artery and mediastinal veins; the right vertebral artery and jugular vein; and the supraceliac aorta and right lower lobe pulmonary artery in a patient with scimitar syndrome. Coil embolization was successful in all cases, though the latter patient required two procedures. CONCLUSION: Anomalous vascular communications in the neck and chest can mimic congenital

heart disease. Percutaneous interventional techniques provide definitive diagnosis and therapy; long-term follow-up will be discussed.

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Tuesday, March 28 Room 316 Scientific Session 16 Chemoembolotherapy MODERATOR:

Michael C. Soulen, MD, Philadelphia,

PA

Comparison of Repeated Transarterial Chemoembolization and Surgical Treatment for Advanced Hepatocellular Carcinoma H.J. Jaeger, MD, Dortmund, Germany F. Castaneda, MD F.M. Hasse K.D. Mathias, MD PURPOSE: Comparison of the survival time of patients with T3 and T4 hepatocellular carcinoma (HCC) treated with repeated transarterial chemoembolization (TAC) or surgical resection. MATERIALS AND METHODS: Thirty-three patients were treated for T3 or T4 HCC. Nineteen underwent complete surgical resection of their tumors, and 14 were treated with repeated TAC, with a suspension of 40 mg of epirubicin, 60 mg of cisplatin, and 10 mL of Lipiodol, at mean intervals of 54 days (range, 32-195 days). A total of 44 TAC procedures were performed, with an average of three per patient (range, one to six). In nine patients (64%)both lobes of the liver were treated, and in five patients (36%) only the right lobe (four had undergone previous resection of the left lobe). RESULTS: The mean survival time was 294 days by life-table analysis for patients treated with surgical resection and 271 days for the patients treated with repeated TAC. After TAC, progressive disease was observed in eight patients (57%)and no change in six patients (43%). CONCLUSION: The survival time of patients with advanced HCC treated with repeated TAC seems comparable to that achieved with surgical resection. Tumor size alone is not a good predictor for the success of TAC.

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Phase I1 Trial of Hepatic Chemoembolization with Ethiodol, Polyvinyl Alcohol, and CAM Chemotherapy for Metastatic Colon Cancer M.C. Soulen, MD, Philadelphia, PA M.J. Pentecost, MD R.A. Baum, MD R.D. Shlansky-Goldberg, MD Z.J. Haskal, MD C. Cope, MD PURPOSE: To assess toxicity of and response to chemoembolization with iodized oil and triple-drug chemotherapy. MATERIALS AND METHODS: Thirty patients with metastatic colorectal cancer underwent 60 chemoembolizations with ethiodol, polyvinyl alcohol, cis-platinum, doxorubicin, and mitomycin C. Response was determined by imaging studies and tumor markers. RESULTS: There were no complete responses. The biological partial response rate was 100% (mean decrease in carcinoembryonic antigen level, 74%). The morphologic partial response rate was 22%. From diagnosis, survival a t 1, 2, and 3 years was 92%, 74%, and 61%, respectively. From first chemoembolization, survival a t 1year was 70%. Three patients died within 30 days of their last embolization. Major morbidity included lobar infarction ( n = 1)and atrial fibrillation with myocardial ischemia ( n = 1). Grade 3-4 toxicities included pain (25%), nausea1 vomiting (5%),and anemia (one patient). CONCLUSION: Chemoembolization with iodized oil and triple-drug therapy is reasonably well tolerated. Response rates and survival for metastatic colorectal cancer may be better than those achieved with systemic chemotherapy; phase I11 trials are warranted.

Intraarterial Chemotherapy and Transient Embolization for Hepatocellular Carcinoma with Doxorubicin, Cisplatin, and Degradable Starch Microspheres A.F. Little, MD, Pittsburgh, PA P.D. Orons, DO B.I. Carr, MD, PhD A.B. Zajko, MD R.L. Baron, MD J.F. McAllister, DO PURPOSE: Regional chemoembolization may improve the response of hepatocellular carcinoma (HCC). This study examined emcacy, hepatotoxicity, and morbidity following three cycles of doxorubicin and cisplatin infused with a transient embolic agent: degradable starch microspheres (DSMs). MATERIALS AND METHODS: Twenty-six patients with HCC were treated. Patients received an escalating drug regimen of 50%, 75%, and 100% of doxorubicin (40 mgIm2 body surface area) and cisplatin

(100 mg/m2)in treatment cycles approximately 28 days apart. Chemotherapeutic agents were delivered selectively into the proper, right, or left hepatic artery with DSMs added to the solution in individualized doses to cause vascular occlusion. Response was graded by means of CT as complete (disappearance of all disease), partial (> 50% decrease in tumor load), minor (< 50% decrease in tumor), no change (no discernible change or < 25% increase in tumor), or progressive disease (2 25% increase in tumor mass). Hepatic toxicity was determined by evaluation of liver enzyme levels and morbidity, by clinical assessment. RESULTS: Twenty-two patients completed a t least three treatment cycles. Eleven demonstrated partial response, two minor response, seven no change, and two progressive disease. Two patients died during the trial, and two were excluded because of the development of arteriovenous shunting. Most patients experienced transient right upper quadrant pain during administration, and one patient developed mild pancreatitis. Transient elevation of liver enzyme levels occurred in five. CONCLUSION: The addition of DSMs to regionally infused chemotherapy may improve response rates of HCC. A randomized comparative study with other chemoembolization regimens is needed. Clinical morbidity and hepatic toxicity are acceptable.

Hepatic Artery Chemoembolization with Collagen, Cisplatin, Doxorubicin, and Mitomycin in Patients with Inoperable Hepatocellular Cancer J.R. Daniels, MD*, Los Angeles, C A S.E. Hanks, MD M.D. Katz, MD D.S. Harrell, MD G.L. Peters, MD PURPOSE: To evaluate response, treatment-associated morbidity, and survival following hepatic artery chemoembolization (HCE) in patients with inoperable hepatocellular cancer (HCC). MATERIALS AND METHODS: Thirty-nine patients with inoperable HCC were treated with HCE between June 1989 and October 1993 a t the Kenneth Norris Cancer Center, University of Southern California. Eligible patients had liver dominant disease and ambulatory performance status; ascites, if present, was well managed with diuretics. HCE was performed with cross-linked collagen mixed with cisplatin, doxorubicin, and mitomycin using microcatheter placement. The whole liver was treated to flow stasis. Multiple procedures were used for very large vascular capacitance of local reccurrence.

1995 SCVIR Meeting Abstracts

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RESULTS: Two patients achieved complete response and 19 partial response for a 54% complete plus partial response rate. Projected median survival was 491 days, with 25% of patients projected to be alive at 1,236 days. There was one procedureassociated death. Five patients, all with CT partial responses, subsequently underwent resection (three patients) or cryosurgery (two patients). Pathologic complete response was seen in two patients, two patients had greater than 95% pathologic necrosis, and one had greater than 50%. CONCLUSION: HCE with collagen, cisplatin, doxorubicin, and mitomycin achieved extended disease control in a significant proportion of patients with hepatoma. Proximal Catheter Positioning during Hepatic Chemoembolization Leads to Decreased Morbidity S.E. Hanks, MD, Los Angeles, CA M.D. Katz, MD D.S. Harrell, MD J.R. Daniels, MD* PURPOSE: To assess the effect of catheter position during hepatic chemoembolization (HCE) on morbidity. MATERIALS AND METHODS: Two hundred eighty-four patients have been treated with 665 HCE procedures since 1988. HCE was performed with cross-linked collagen mixed with cisplatin, doxorubicin, and mitomycin. The initial experience in 1988-1989 (31 patients) used a distally placed microcatheter in second- or third-order hepatic arterial branches. A gradual transition from this distal technique to a more proximal catheter position (usually proper, right, or left hepatic artery) occurred in 1990. This technique evolution was intended to reduce the density of collagen particles in mediansized vessels to reduce liver injury and maintain hepatic arterial patency. Since 1991, 133 patients have had HCE from a proximal catheter position. RESULTS: Complication rates for all years were 13%, and procedure-associated deaths were 2%. With distal HCE, complications reached a high of 35%, and hospitalizations averaged 4.6 days. With proximal technique, yearly complication rates were 7% or less, and hospitalizations averaged 1.3 days. There have been no procedure-associated deaths among the 112 patients treated since 1991. The decrease of morbidity was seen in both good performance status and high-risk patients. CONCLUSION: Modification of catheter position to a proximal position during chemoembolization has markedly reduced days in hospital and complications following HCE.

Hepatocellular Carcinoma Supplied by the Inferior Phrenic Artery: Results of Transcatheter Oily Chemoembolization in 50 Patients J.W. Chung, MD, Seoul, Korea J.H. Park, MD J.K. Han, MD K.M. Yeon, MD M. C. Han, MD PURPOSE: To evaluate the efficacy and safety of transcatheter oily chemoembolization therapy (TOCE) via the inferior phrenic artery (IPA) in a hepatocellular carcinoma supplied by it. MATERIALS AND METHODS: During the past 3 years, 50 patients with a hepatocellular carcinoma underwent a total of 77 procedures of TOCE via the IPA as well as the hepatic artery. The tumor was larger than 5 cm in 32 patients. TOCE was performed with 3-15 mL of iodized oil-doxorubicin hydrochloride emulsion administered through microcatheters. Embolization with gelatin sponge particles followed in 32 patients. We analyzed complications and efficacy of the procedure with CT, serum a-fetoprotein measurements, and angiographic follow-up. RESULTS: Twenty-seven patients complained of shoulder pain immediately after the procedure. Other complications were pleural effusion and basal atelectasis in four patients, and hemoptysis and intractable hiccup in each patient. All of these complications were transient and resolved spontaneously. At follow-up evaluation, complete or partial remission of the tumor was noted in 15 and 17 patients, respectively. The major causes of treatment failure in the remaining 18 patients were the presence of other extrahepatic collaterals ( n = 7), uncontrolled hepatic arterial supply ( n = 81, and angioinvasion ( n = 3). CONCLUSION: TOCE via the IPA is a safe and effective adjunct to TOCE via the hepatic artery in the management of a hepatocellular carcinoma supplied by the IPA.

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Journal of Vascular and Interventional Radiology

January-February 1995

Tuesday, March 28 b o r n 305 Scientific Session 17 Dialysis Access Interventions MODERATOR:

Kevin L. Sullivan, MD, Philadelphia,

PA

Percutaneous Interventions for Failing Hemodialysis Access Fistulas D.J. Bourgeois, MD, Kingston, Ont C.L. Meers, R N E.B. Toffelmire, MD E. Carmody, MD PURPOSE: To evaluate the efficacy of percutaneous interventions in salvage of failing or thrombosed dialysis access arteriovenous fistulas (AWs). MATERIALS AND METHODS: Medical records and films of patients referred for investigation and treatment of malfunctioning or thrombosed dialysis AVFs were reviewed. Forty-five patients are included who underwent 31 angioplasties and 17 courses of thrornbolysislangioplasty. Information regarding location, morphology, and results of therapy of stenoseslocclusions were collected, as well as data on patency rates and the need for subsequent intervention. RESULTS: Patients were followed up for 1-26 months (mean, 9 months). Angioplasty was technically successful in 97% (30 of 31). Unassisted patency rates were 93%, 88%, 78%, and 60% at l , 3, 6, and 9 months. Thrombolysis and angioplasty were technically successful in 76% (13 of 17). Unassisted patency rates of 92%, 82%, 57%, and 50% at 1, 3, 6, and 9 months were obtained. Multiple procedures were necessary in eight patients. Excluding initial failures, the rates of assisted patency were loo%, 96%, 90%, 86%, and 76% a t 1, 3, 6, 9, and 12 months. CONCLUSION: (1)Percutaneous techniques effectively maintain dialysis A W function. (2) Successful treatment is more likely with stenosed than with thrombosed AWs. (3) Secondary patency of dialysis AVFs is greater than that for dialysis grafts. Admixture of Heparin to Urokinase to Decrease Thrombolytic Time and Urokinase Dose in Polytetrafluoroethylene Dialysis Graft Recanalization D.S. Harrell, MD, Los Angeles, CA M. Kozlowski, MD M.D. Katz, MD S.E. Hanks, MD PURPOSE: To determine if the addition of heparin to urokinase during dialysis graft thrombolysis can

lower urokinase dose, shorten procedure time, and thereby decrease costs. MATERIALS AND METHODS: We retrospectively looked at patients undergoing polytetrafluoroethylene (PTFE) graft thrombolysis during the last 18 months. Twenty cases were performed with urokinase alone, while 19 cases were treated with a combination of urokinase and heparin. Thrombolysis was performed in the angiography suite via crossed catheter technique. Urokinase was administered directly into the thrombus. In patients receiving heparin, 5,000 IU was added directly to the initial urokinase solution. Thrombolytic time was defined as initial urokinase administration until case completion, including ancillary angioplasty or Wallstent placement. RESULTS: In patients who received urokinase alone, an average of 750,000 U of urokinase was used, with an average procedure time of 2 hours 42 minutes. When heparin was added to the urokinase, an averge of 435,000 U was used, with an average procedure time of 2 hours. The addition of heparin, therefore, yielded an average savings of greater than one vial, 315,000 U, of urokinase and 42 minutes of procedure time. CONCLUSION: Thrombolysis is an effective but costly method of recanalizing PTFE dialysis grafts. The addition of heparin directly to urokinase can decrease both urokinase dose and thrombolysis time, thereby reducing cost. 99

3:OO PM

Comparison of Pulse-Spray with High-Dose Infusion Delivery of Urokinase for Thrombolysis of Thrombosed Dialysis Access Grafts S.C. Goodwin, MD, Los Angeles, CA M.K. Razavi, MD T.O. McNamara, MD H. Yoon, MD, PhD PURPOSE: To compare pulse spray thrombolysis with high-dose infusion thrombolysis in thrombosed dialysis access grafts. MATERIALS AND METHODS: Thirty patients with thrombosed dialysis access grafts were included in the study. In 15 patients, pulse spray pharmacomechanical thrombolysis was used. In the second group of 15 patients, high-dose infusion of urokinase was used a t a rate of either 8 or 10,000 Ulmin. All patients were fully anticoagulated with heparin. RESULTS: Thrombolysis was successful in 14 of 15 patients in the pulse spray group and all 15 patients in the high-dose infusion group. This difference was not statistically significant. In the pulse spray group, the mean infusion time to thrombolysis was 72 minutes. The mean dose was 586,000 U. In

1995 SCVIR Meeting Abstracts 39 Volume 6 Number 1

the high-dose infusion group, the mean infusion time to thrombolysis was 55 minutes. The mean dose was 479,000 U. These differences are not statistically significant. CONCLUSION: No statistically significant difference was found in either mean time to thrombolysis or total dose of urokinase utilized in the two groups. It is possible that the fast thrombolysis times reported with pulse spray thrombolysis are a t least in part attributable to the high dose rates used.

Venous Stents for Peripheral and Central Vein Stenosis in Hemodialysis Patients G.B. Lund, MD, Baltimore, MD S.O. Trerotola, MD S.E. Mitchell, MD S.J. Sauader, MD A.C. Venbrux, MD F.A. Osterman, Jr, MD PURPOSE: To establish patency rates after venous stenting of stenosed peripheral and central veins in hemodialysis patients. MATERIALS AND METHODS: Twenty-six intravascular stents (two Z stents, 23 Wallstents, one Palmaz stent) were used for peripheral ( n = 7) and central ( n = 19) stenoses ( n = 20) or occlusions ( n = 5) in 20 patients. Clinical, angiographic, and hemodynamic data were collected. The cumulative probability of patency was determined by using lifetable analysis. Values are expressed as means and ranges. RESULTS: All stent placements were successful. Central migration of two Wallstents occurred. Seven of 11 central and two of seven peripheral stents were patent after 162 days (15-390 days) and 341 days (186-496 days), respectively. Eleven of 19 central and five of seven peripheral stents had restenosed after 162 days (14-496 days) and 179 days (33504 days), respectively. The cumulative probability of primary patency was 57% at 6 months and 29% at 12 months for central stents, and 42% at 6 months and 12 months for peripheral stents. Twelve procedures were performed to restore patency in restenosed stents. The cumulative probability of assisted patency was 73% at 6 months and 63% at 12 months for central stents, 85% a t 6 months and 47% at 12 months for peripheral stents. CONCLUSION: Venous stent placement extends the use of existing dialysis access routes. Patency rates exceed those reported for angioplasty.

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101 3:30 PM Venous Stent Placement for Complications of Hemodialysis M.S. Webb, MD, Prouidence, RI T.P. Murphy, MD R.E. Lambiase, MD G.S. Dorfman, MD R.A. Haas, MD J.M. Rogg, MD, et a1 PURPOSE: To evaluate the use of intravenous stents in the treatment of dialysis fistula dysfunction and extremity swelling in patients undergoing long-term hemodialysis. MATERIALS AND METHODS: Twenty patients with dialysis fistulas and symptomatic venous stenoses were identified and treated. Eleven patients were treated for fistula dysfunction, seven for arm swelling, and two patients with both. Five of the lesions were located either in the fistula or a t the anastomosis and 15 of the lesions were in veins proximal to the fistula. Venous stenoses were diagnosed venographically and treated with primary stent placement (Wallstents) and angioplasty. Clinical follow-up is available on all patients. RESULTS: Technical success rate was 95%. There were no major complications. Arm swelling resolved in all patients and fistula function was salvaged in all technical successes. Patients were followed up for a mean of 6.2 months ? 8.0. Primary patency was 78% a t 6 months and 22% at 1 year. Secondary patency was 88% at 6 months and 42% a t 1 year. CONCLUSION: Intravascular stents provide a safe and effective therapy for central vein stenosis and are useful in the preservation of failing dialysis fistulas. Percutaneous Arteriovenous Graft Creation in an Animal Model S.O. Trerotola, MD*, Indianapolis, IN T. Winkler, BS R. G. Dreesen, AS PURPOSE: To develop a technique for percutaneous creation andlor revision of arteriovenous hemodialysis access grafts, and to study the feasibility of the technique in the acute setting. MATERIALS AND METHODS: Arteriovenous shunts, consisting of silicone covered Wallstents 6 ( n = 7) or 8 ( n = 1)mm in diameter and 11-18 cm in length, were created in mongrel dogs. All shunts were created percutaneously except one, in which the carotid artery was exposed surgically and the jugular vein accessed percutaneously to create a straight external graft. All other grafts were femoral loops (femoral artery to femoral vein). Five were tunneled subcutaneously and three left external for this acute study. All shunts were delivered through 10-F peel-away sheaths.

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Journal of Vascular and Interventional Radiology

January-February 1995

RESULTS: To date, eight shunts have been created and have been allowed to flow for a mean of 4 hours (range, 1-6 hours) prior to sacrifice. Leakage around the anastomoses has not been observed. Leaks in the silicone covering have been problematic, resulting in one early shunt failure. CONCLUSION: Percutaneous arteriovenous shunt creation is feasible through acceptably small sheaths. Peel-away sheath placement of the stent circumvents the technical problem of placing a closed device into both artery and vein. The unsutured, unanchored "anastomoses" created are hemostatic in the acute setting. This technique has the potential to allow percutaneous revision of existing hemodialysis access grafts and possibly de novo creation of grafts in humans.

Wednesday, March 29 Room 315 Scientific Session 18 Peripheral Stent-Grafts MODERATOR: Joseph Bonn, MD, Philadelphia, PA

Transluminal StenUGraft Management of Isolated Iliac Artery Aneurysms M.K. Razavi, MD, Stanford, CA C.P. Semba, MD R.P. Liddell, MD U.R. Nyman, MD M.D. Dake, MD S. T. Kee, MD PURPOSE: To evaluate the safety and effectiveness of percutaneous placement of endovascular stentgraft prostheses for the treatment of isolated iliac artery aneurysms. MATERIALS AND METHODS: Six iliac aneurysms in five patients were treated with transluminally placed endovascular stent-graft devices. Three were in the common iliac artery, and three involved both the common and external iliac arteries. The mean age of the patients was 70 years, with a range of 54-84 years. Of the six aneurysms, five were treated with a self-expanding stainless steel stent covered with a woven Dacron graft. The other was treated with a balloon-expandable stent covered with polytetrafluoroethylene graft material. RESULTS: Transluminal placement of the stentgraft prostheses was technically successful in all cases with thrombosis of the aneurysmal portion of the vessels. There were no distal thromboembolic events, deaths, or infections. The course in one patient was complicated by deep vein thrombosis of

the ipsilateral iliac vein, which was treated with systemic heparinization. CONCLUSION: Early results show transluminal placement of stent-graft prostheses for treatment of isolated iliac aneurysms to be a safe and effective alternative to surgery in those patients who are poor surgical candidates.

Percutaneous Endoluminal Grafting for Iliofemoral Aneurysmal and Occlusive Disease C.O. Papazogloy MD, Phoenix, A2 E.B. Diethrich, MD L.A. Lopez-Galarza, MD J. Rodriguez-Lopez, MD PURPOSE: To examine if endoluminal grafts (ELGs) can successfully exclude aneurysms and increase the efficacy of interventional therapy for lengthy occlusive disease. MATERIALS AND METHODS: Expandable polytetrafluoroethylene tube ELGs with Palmaz stent fixation have been implanted by means of a low-profile percutaneous delivery system in 39 limbs of 35 patients for a variety of conditions (occlusions in 20, stenoses in six, elective aneurysm exclusion in six, postdilation dissection in one, emergent treatment of arterial rupture in four, femoropopliteal bypass graft distal anastomotic stenosis in two, and femorotibia1 vein graft rupture in one). RESULTS: Forty-one ELGs were successfully implanted in 37 limbs (95%procedural success). Two failures occurred: one in an aneurysm and one in a superficial femoral artery (SFA) occlusion. Four grafts migrated during deployment but were retrieved and implanted, one collapsed graft was redilated, and one distal dilation-related dissection was stented. Procedural complications included five access-site sequelae secondary to large sheaths used early in the series and three ELG thromboses; two of the thromboses were treated successfully, but the third required bypass grafting at 15 days. At up to 1year follow-up, 38 grafts (93%) are patent (two SFA ELGs occluded in 1 3 months). Notably, no intima1 hyperplasia was seen on stents examined angioscopically at 8 months; polytetrafluoroethylene may block myoproliferative migration. CONCLUSION: ELGs appear promising as a means of excluding aneurysms and internally bypassing lengthy occlusions; further investigation is warranted.

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Initial Experience of Endoluminal Bypass Grafting in Leg Arteries with the Cragg Endopro System 1: Report of the First 64 Cases M. Henry, MD, Essey Les Nancy, France M. Amor, MD G. Etheuenot, MD I. Henry, MD M. Allaoui, MD E. Le Borgne, MD, et a1 PURPOSE: To evaluate a new expandable nitinol stent covered with a polyester woven fabric, the Cragg Endopro System 1, which enables percutaneous bypass grafting in iliac and femoropopliteal arteries. MATERIALS AND METHODS: Sixty-four symptomatic patients (54 male, 10 female; mean age, 68 years; range, 54-88 years) with predominantly lengthy stenotic (n = 31) or occlusive ( n = 28) lesions or aneurysms (n = 5) in iliac ( n = 221, femoral ( n = 40) or popliteal (n = 2) arteries received 92 stents. The mean length of femoropopliteal lesions was 14 cm + 1.8 (range, 5-30 cm); of the femoral lesions, 6.7 cm + 0.8 (3-13 cm) (P < .01). The mean percentage of stenosis was 89% -t 2%. RESULTS: Immediate technical success was achieved in 98% (63 of 64 patients). Ten complications occurred. One distal embolism in the femoral artery was cured by fibrinolysis and balloon catheter embolectomy. Of five acute thromboses (one iliac, four femoral), four were cured by thromboaspiration and fibrinolysis, and one required a bypass. Of four thromboses between days 15 and 30, one was recovered by balloon catheter embolectomy, one required a bypass, and two were treated medically. Nineteen patients had fever and pain in the leg during several days. Over 11 months of follow-up, all iliac stents remained patent. Of four restenoses a t the femoral level, three were cured by new angioplasty and one required surgery. The secondary patency rates were 100% a t the iliac level and 88% at the femoral. CONCLUSION: The Cragg Endopro System 1 seems to be safe and effective in long lesions and aneurysms. The mid- and long-term results of this percutaneous bypass are being studied.

Endoluminal Grafts for Peripheral Aneurysms H.P. Rousseau, MD, Toulouse, France F. Joffre P. Otal PURPOSE: We studied the feasibility and efficacy of intraluminal grafting for treatment of peripheral aneurysms and obstructions. MATERIALS AND METHODS: Ten self-expanding Cragg stents covered with thin-walled heparin-im-

pregnated Dacron were implanted in seven patients. One subclavian, two iliac, and three popliteal aneurysms (one thrombosed) and one femoral obstruction were treated. All stent grafts were introduced through a 10-F sheath placed percutaneously. The stents ranged from 8 to 10 mm in diameter, and the mean length of the lesions was 15 cm (range, 5-25 cm). Clinical, color Doppler, and arteriographic follow-up was obtained in all cases. RESULTS: In all cases the covered stents were successfully implanted. In three cases multiple stents were used to cover all the lesions. No com~lications were observed during the procedure, and only one obstruction was observed in a popliteal aneurysm a t 15 days. Except for this case treated by bypass surgery, all stented grafts were patent, and the aneurysms were completely excluded over a mean followup of 4 months (range, 3-6 months). CONCLUSION: Endovascular covered Cragg stents offer high technical success in treating peripheral aneurysms, and their use is an alternative to surgical bypass. 107 2:45 PM Cragg Covered Stent: Preliminary Results C.P. Delcour, MD, Charleroi, Belgium F. Alsaid, MD J. Rommens, MD E. Van Dueren, MD G. Verhelst, MD G. Bruninx, MD PURPOSE: To investigate the efficacy of endovascular covered stents in the treatment of occlusions and aneurysms of iliac arteries and in the managment of venous restenosis. MATERIALS AND METHODS: The device consists of a self-expanding nitinol stent covered by an ultrathin woven polyester fabric. From October 1993 through August 1994, 13 patients were treated. All stent-grafts were introduced through an 11-or 12-F sheath. After correct positioning of the stent-graft, the sheath is withdrawn to deploy the endoprosthesis. Five patients had occlusion of an iliac artery. Recanalization was performed with a hydrophilic guide wire followed by balloon angioplasty and subsequent stent placement. Six patients had iliac (five cases) or femoral (one case) artery aneurysms. One case of cephalic vein restenosis (hemodialysis shunt) and two cases of iliac stenosis were also treated. The stents were 6-10 mm in diameter and 3-6 cm long. Clinical follow-up, repeated Doppler studies, and intravenous DSA were performed in all patients. RESULTS: Immediate technical success was achieved in all cases. The mean follow-up is 5.5 months (range, 1-10 months). In patients with stenosis or occlusions, restenosis occurred in three

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cases. In the group of aneurysms, multiple follow-up venograms demonstrate continued patency, with exclusion of the aneurysms in all cases. CONCLUSION: The preliminary results of this study suggest that covered stents are effective devices in the treatment of iliac aneurysms and may become an alternative to surgical treatment. More investigation is needed to evaluate the advantages of covered stents in the treatment of stenosis or occlusions. Initial Clinical Experience with t h e Cragg Endoluminal Graft i n Treating Long Iliac Stenosis J. Pernes, PhD, Antony, France M. Auguste, PhD D. Hovasse, PhD J. Lasry, MD P. Gignier, PhD PURPOSE: To determine the effectiveness of a selfexpanding nitinol stent covered by a polyester fabric in long iliac stenosis. MATERIALS AND METHODS: Twelve patients with iliac artery stenosis 5-10 cm in length (mean, 6 cm) were treated percutaneously with a Cragg endoluminal graft after unsuccessful PTA (11 PTAinduced dissections, one partial rupture at the angioplasty site). In five cases, US and angiography showed aneurysmal calcified lesions associated with the long iliac stenosis. RESULTS: Twelve Cragg endoluminal grafts (8 mm to 6 cm) were easily implanted through an ipsilatera1 approach with a 9-F introducer, in a technique similar to vena cava filter implantation. All cases showed angiographic restoration of patency and elimination of the dissection flap without any residual stenosis. One internal iliac artery has been covered without clinical complication. In the case of the arterial rupture after balloon inflation, bleeding was stopped by the covered stent and the efficacy of the endoluminal treatment was surgically confirmed. At 3 months, 11 patients are asymptomatic with a mean ankle-brachial index of 0.95 k 0.1, and in one patient a stent occlusion has been observed. CONCLUSION: The Cragg endoluminal graft seems to be safe and effective in long stenosed iliac lesions, historically not well suited for balloon angioplasty alone.

Wednesday, March 29 Room 316 Scientific Session 19 Percutaneous Drainage MODERATOR:

Daniel Picus, MD, St Louis, MO

Drainage a n d Sclerotherapy of Malignant Pleural Effusion with Image-guided Chest Catheters M.A. Braun, MD, Chicago, IL R.L. Vogelzang, MD A.A. Nemcek, Jr, MD PURPOSE: Image-guided chest catheter drainage of malignant pleural effusions causes less chest wall pain and offers precise image-guided placement. The treatment goals are symptomatic relief achieved by complete drainage of the pleural effusion followed by pleurodesis. Malignant pleural effusions are complex, containing loculations, tumor deposits, and hemorrhage. Adjunctive urokinase fibrinolysis allows rapid and complete evacuation of complex malignant effusions. MATERIALS AND METHODS: Twelve patients were treated for malignant pleural effusions. Etiologies included renal (n = 1)and breast (n = 6)carcinoma, adenocarcinoma (n = 41, and sarcoma (n = 1).The drains used were 12-14 F locking pigtails. Six of the 12 patients were treated with three to six 80,000-U doses of urokinase. Three patients were treated with doxycycline sclerotherapy and two with talc sclerotherapy. RESULTS: In the six patients treated with urokinase fibrinolysis, the preurokinase average drainage was 1,334 mL of fluid and the posturokinase average drainage was 985 mL. Two of three patients treated with doxycyclirie pleurodesis had symptomatic improvement. Both patients treated with talc pleurodesis had symptomatic improvement. CONCLUSION: Drainage of malignant pleural effusions can be effectively performed through small image-guided catheters. An expeditious drainage can be achieved when urokinase fibrinolysis is performed. Both doxycycline and talc pleurodesis can be effectively performed through small catheters. Management of Protracted Drainage from Postoperative Lymphoceles R. Sawhney, MD, Sun Diego, CA S. Zinck, BS S.C. Rose, MD H.B. D'Agostino, MD PURPOSE: Persistent output from catheters following percutaneous drainage of postoperative lympho-

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celes is common. The purpose of this study is to assess the effectiveness of ~ercutaneouscatheter drainage combined with repeated sessions of alcohol instillation in the treatment of protracted drainage from lymphoceles. MATERIALS AND METHODS: Ten patients with postoperative lymphoceles underwent percutaneous drainage. Lymphoceles developed following renal transplantation (seven patients), radical prostatectomy (one patient), radical hysterectomy (one patient), and bilateral inguinal lymphadenectomy (one patient). Indications for drainage included pain, hydronephrosis, lower extremity edema, and sepsis. Drainage catheters were placed under sonographic guidance (eight cases) or CT guidance (two cases). Protracted drainage was defined as persistent drainage for more than 4 weeks. Seven patients received sclerotherapy with absolute alcohol (10-50 mL per session; one to three sessions per day). RESULTS: Resolution of the lymphocele was achieved in eight of 10 patients (80%). There were two recurrences (one infected). These were treated successfully with repeated drainage and sclerosis. The mean duration of catheterization was 33 days (range, 1-58 days). CONCLUSION: Catheter drainage combined with repeated alcohol instillation is safe and effective in the treatment of protracted drainage from postoperative lymphoceles.

111 2 : 1 5 ~ ~ Anaerobic Culture Yield in Interventional Radiologic Drainage Procedures E.S. Malden, MD, St Louis, MO D. Picus, MD W.C. Dunagan, MD PURPOSE: This study was designed to determine the yield of anaerobic cultures from percutaneous radiologic drainage procedures. MATERIALS AND METHODS: Anaerobic culture results in 232 patients from June 1992 to May 1994 were retrospectively examined. Anaerobic specimens were placed in specially designed anaerobic culture tubes and not blood culture media. Procedures included percutaneous nephrostomy (97 patients), biliary drainage (57 patients), and abdominal abscess drainage (77 patients). Aerobic culture results were tabulated in those patients with positive anaerobic cultures. RESULTS: Overall, 10% of patients (n = 24) had positive anaerobic cultures (Bacteroides species, n = 16; Clostridium species, n = 5; other organisms, n = 3). Anaerobes were isolated in 18% (n = 14) of abscess drainages, 7% (n = 7) of nephrostomy drainages, and 5% (n = 3) of biliary drainages. Aer-

obic isolates were present in 88% (n = 21) of patients with anaerobic infection. CONCLUSION: The yield for anaerobic cultures varies for different types of drainage procedures. Cultures of abdominal abscesses yield anaerobes helpful in guiding therapy in a significant number of cases. Biliary drainage has a lower anaerobic isolation rate. Finally, the yield of anaerobes in nephrostomy drainage is surprisingly high, and we are currently pursuing the clinical significance of this finding.

Percutaneous Gallstone Removal: Long-term Follow-up C.S. Courtois, MD, St Louis, MO D. Picus, MD M.E. Hicks, MD M.D. Darcy, MD T.M. Vesely, MD S.A. Edmundowicz, MD, et a1 PURPOSE: The purpose of this study is to evaluate stone and symptom recurrence rates as well as related long-term complications and life expectancy following percutaneous gallstone removal (PGR). MATERIALS AND METHODS: The medical records were reviewed in 87 patients, most a t prohibitive surgical risk, undergoing PGR between 1987 and 1992. Physicians and patients were contacted by telephone for clinical follow-up. Twenty-nine patients have returned for follow-up US. RESULTS: The mean patient age was 69 years -t 14. The indication for gallbladder drainage was emergent in 53 (61%) and elective in 34 (39%). Stones were located in the gallbladder in 85 (98%), cystic duct in 24 (28%), and common bile duct in 19 (22%) patients. The technical success rate was 92%. The overall complication rate was 19.5%. US followup, ranging from 1month to 2.5 years after the procedure (mean, 11.4 months), shows a gallstone recurrence rate of 37.9%. To date, clinical follow-up has been obtained in 31 patients and the overall symptom recurrence rate is 16.1%. CONCLUSION: The stone recurrence rate is high for PGR but comparable to that for other gallbladder sparing procedures. Given the actual symptom recurrence rate and the advanced age of the patient population, PGR remains a viable option for patients at high surgical risk.

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Percutaneous Cholecystostomy: Clinical Experience and Factors Affecting Outcome V.G. McDermott, MD, Durham, NC R.E. England, MD P.V. Suhocki, MD G.E. Newman, MD C.S. Payne, MD T.P. Smith, MD, et a1 PURPOSE: To determine factors that might predict which patients are likely to benefit from percutaneous cholecystostomy (PC) performed for suspected acute cholecystitis. MATERIALS AND METHODS: Between 1988 and 1994, 61 patients (37 male, 24 female; mean age, 59 years) underwent PC for suspected acute cholecystitis. Clinical records and radiologic investigations were reviewed retrospectively. Response to PC was defined as resolution of symptoms, normalization of white blood cell count, and defervesence within 72 hours of the procedure. Statistical analysis was performed with the Fisher exact probability test. RESULTS: Fifty-nine procedures were technically successful. Forty-two patients had clinical signs suggesting cholecystitis (pain and tenderness); 34 (81%) responded to PC. Seventeen patients had fever of unknown cause and abnormal gallbladder imaging; nine (53%) responded. This difference was statistically significant (P = .006). Correlation of response with imaging findings alone showed no correlation between response and the presence of gallstones, gallbladder wall thickening, or gallbladder distention. Pericholecystic fluid was found to correlate with response (P = .03), as did the presence of multiple imaging abnormalities (P = .039). CONCLUSION: PC is most likely to be successful if the patient has (1)clinical findings to collaborate gallbladder imaging abnormalities, (2) pericholecystic fluid, or (3) multiple radiologic abnormalities to suggest cholecystitis.

Percutaneous Radiologic, Surgical Endoscopic, and Endoscopic Gastrostomy/Gastrojejunostomy: Comparative Study and Cost Analysis J.M. Barkmeier, MD, Indianapolis, I N S.O. Trerotola, MD J.J. Snidow, MD V. J . Harris, MD E. Wiebke, MD S. Sherman, MD PURPOSE: In our hospital, there are three competing modalities for direct gastric access: surgical endoscopic (SEG), percutaneous endoscopic (PEG), and percutaneous radiologic (PRG). This study compared the results and overall costs of these techniques. MATERIALS AND METHODS: Medical records were reviewed from 116 procedures (32 SEG, 44 PEG, 40 PRG) performed over a 2-year period. Indi-

cations, complications, and follow-up procedures were tabulated. Costs of the initial procedure and any related subsequent procedure were calculated. RESULTS: Age and sex distribution were similar in all groups. Indications varied somewhat based on referral patterns. Success rates were as follows: 88% for PEG, 100% for SEG, and 100% for PRG. Of patients in whom PEG failed or was refused (n = 91, eight underwent PRG and one SEG. No patient refused PRG or SEG. Complications were similar in all groups. Costs for the initial procedure were $1,559 for PEG, $2,292 for SEG, and $1,831 for PRG. Conversion from SEG (n = 2) or PEG (n = 3) was performed fluoroscopically at a cost of $1,327. CONCLUSION: While PEG is the least expensive modality, it may not be the most cost effective due to a lower success rate and follow-up procedures (conversions to gastrojejunostomy, endoscopy to remove catheter). SEG is desirable when performed in conjunction with other surgical procedures but is more costly, largely due to anesthesia and operating room cost. PRG is safe, effective, and relatively inexpensive; it is particularly desirable when gastrojejunostomy is needed.

Wednesday, March 29 Room 305 Scientific Session 20 Genitourinary Interventions MODERATOR: David M. Hovsepian, MD, St Louis, MO

Alcohol-induced Sclerosis of the Spermatic Vein: Results in 66 Men L.S. Machan, MD, Vancouver, BC L. Goldenberg, MD W. Taylor, MD C. Krahn, MD M. Nigro, MD PURPOSE: To evaluate the safety and efficacy of alcohol sclerosis of the spermatic vein. MATERIALS AND METHODS: At the time of coil embolization of the spermatic vein, sufficient collateral channels were visualized that alcohol sclerosis was required to achieve spermatic vein occlusion. Sixty-six infertile men with oligospermia and varicoceles (58 unilateral, eight bilateral) were treated in this manner. In the first 20 men, the alcohol was injected into the spermatic vein as a single bolus. In 46 subsequent patients, alcohol was injected in 0.5mL doses while the catheter was withdrawn along the course of the spermatic vein. Postabstinence

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sperm counts were obtained a t least 6 weeks after embolization and compared with pretreatment counts. RESULTS: Seventy-six of 76 spermatic veins were successfully occluded. The mean alcohol dose was 2.5 mL. Six of 20 of the patients receiving a single bolus had severe pain, two with hematuria, lasting a t least 1week (range, 8 days to 1.3 years). Two of 46 men receiving multiple small injections of alcohol had postprocedure pain, both lasting less than 1 week. Forty-one of 52 men followed up to date had improved semen analysis a t 6-12 weeks. CONCLUSION: Alcohol sclerosis of the spermatic vein requires meticulous technique but is safe and effective when embolization with coils alone is not adequate.

Anastomosis between the Spermatic Venous and Portal Systems: A Retrospective Study of 500 Venographies A.F. Le Blanche, MD, Paris, France F.P. Boudghene, MD J.R. Bigot, MD M.F. Carette, PhD M. Bazot, MD N. Gagey, MD, PhD PURPOSE: To systematize venous portospermatic anastomosis, a cause of recurrence of varicoceles. MATERIALS AND METHODS: Five hundred consecutive spermatic venographic studies were retrospectively reviewed. Average patient age was 27.8 years old (range, 11-65 years) and patients did not have caval and/or portal abnormalities. The indications were varicoceles with oligoasthenospermia (89%), pain (9%), or infertility prevention (2%). After bilateral catheterization, sclerosis was undertaken a t the level of the sacroiliac joint. RESULTS: Sixty-eight percent of the varicoceles were left sided, 2% were right sided, and 30% were bilateral. For the left side, of 10.2% with anastomosis, one went to the splenic vein (0.2%); 20 went through the colic fascia to the caudal mesenteric vein (4%); five went to the colic veins, a t the level of L-3 to L-4 (1%); and 25 valved veins in front of L-5 went to the colic system (5%). For the right side, of 28.2%, two voluminous (1.2%) and 34 thin (20%) anastomoses went to the cranial mesenteric vein through the right colic fascia, and 12 were lateral, anastomosed to the colic system with average diameter equal to or larger than the spermatic vein (7%). CONCLUSION: Portosystemic anastomoses are underestimated because of the low-pressure injection in the supine position. They are more frequently observed on the right side, and their localization is necessary before sclerosis.

Recurrent Postsurgical Varicoceles: Treatment with Embolization E. O%rady, MB J. Warner, MD R. Stogryn, MD W. Taylor, MD M. Nigro, MD L. S. Machan, MD, Vancouver, BC PURPOSE: To evaluate the efficacy of fluoroscopically guided embolization of recurrent varicoceles after surgical ligation. MATERIALS AND METHODS: Twenty men aged 22-52 years (mean, 36.5 years) presenting over a 4year period were treated between 4 months and 20 years after surgery (mean, 50 months) with embolization. Five patients had symptomatic varicoceles, and 15 were infertile. The varicoceles were nonpalpable in one of five symptomatic and seven of 15-infertile patients. Eighteen patients had undergone previous left-sided surgery; two (with left-sided recurrences only) had undergone bilateral surgery. Three subclinical right varicoceles were found and treated a t the time of embolization. RESULTS: Twenty of 20 recurrent left-sided and three of three subclinical right varicoceles were successfully embolized. Twenty-one of 23 varicoceles were embolized with coils alone and two with coils and alcohol. Complete resolution was achieved in four of five symptomatic varicoceles; one case was lost to follow-up. Follow-up of 15 infertile men (7-44 months) revealed that five of 15 have achieved pregnancy, five have improved sperm counts but no pregnancy, three have no change in sperm count, one refused sperm count and has no pregnancy, and one was lost to follow-up. CONCLUSION: Varicocele embolization is a safe and effective procedure for postoperative recurrent varicoceles. This is a n important source of referral of patients who might otherwise be denied further surgical procedures.

Cure of Uterine Synechiae by Using Dilation with Angioplasty Balloons: Preliminary Results F.P. Boudghene, MD, Paris, France J. Antoine, MD M. Bazot, MD J.R. Bigot, MD PURPOSE: To evaluate the feasibility and the efficacy of the treatment of intrauterine synechiae with angioplasty balloon dilation. MATERIALS AND METHODS: Over a 2-year period, 10 infertile patients (average age, 35 years) were treated with intrauterine dilation, to cure corporeal ( n = 3) or cervicoisthmic ( n = 7) uterine synechiae. This procedure was performed on an outpa-

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tient basis under fluoroscopic control. A guide wire served to catheterize the uterine cavity crossing the stenosis and to insert an 8 x 20-mm angioplasty balloon that was positioned and inflated at the level of the synechia. RESULTS: In all the cases the uterine cavitv was successfully catheterized. Cure of synechiae was obtained in six cases, remained incomplete in three cases, and was impossible in one case. Cervicoisthmic synechiae were more easy to treat than corporeal synechiae, which were usually incompletely cured. During this study the procedure was well tolerated by all patients. One patient became pregnant within 1year. CONCLUSION: Cure of synechiae with angioplasty balloons is a nontraumatic mode of treatment of such uterine disease that is less risky than operative hysteroscopy. It may be proposed in some cases of infertile patients and is recommended to treat isthmic synechiae.

Diagnostic Selective Salpingography in Infertile Women L.S. Machan, MD, Vancouuer, BC L. Jessurun, MD N. Lee, MB, ChB T. Rowe, MB, ChB P. McComb, MB, ChB PURPOSE: To evaluate the results of selective salpingography in infertile women with nonspecific findings at conventional hysterosalpingography (HSG). MATERIALS AND METHODS: One hundred twenty-one fallopian tubes were selectively cannulated and injected in 71 infertile women who had previously undergone HSG. The indications for selective salpingography were nonconclusive HSG results or discordance between HSG findings and clinical findings. RESULTS: There were findings of salpingitis isthmica nodosa in 38 tubes, tubocornual polyps in eight, and distal tubal occlusion in 30; 11 were patent after surgery, and 34 were normal. Eighty-four tubes had been reported as occluded or nonfilling, 34 showed partial filling insufficient for diagnosis, and three were reported as normal at conventional HSG. CONCLUSION: Selective salpingography provides additional diagnostic information in addition to that available from conventional HSG.

Sterilization with Fallopian Tube Occlusion by Using Methylcyano-acrylateand a Nonsurgical Transvaginal Approach in Rabbits G.S. Berkey, MD, Philadelphia, PA R.C. Nelson, MD A.M. Zuckerman, MD D. Dillehay, PhD PURPOSE: To evaluate a nonsurgical, nonhormonal sterilization procedure using transvaginal microcatheterization techniques and methylcyano-acrylate (MCA) as a sclerosing agent. MATERIALS AND METHODS: Seventeen adult virgin female rabbits underwent bilateral fallopian tube cannulation through a nonsurgical transvaginal approach using a coaxial catheter system with fluoroscopic guidance. Fourteen of the rabbits underwent bilateral fallopian tube occlusion by direct MCA (0.3 mL) injection, and the remaining three were separated as controls. Three of the rabbits with tubal occlusion were killed as temporal histologic controls. The remaining 11 rabbits with occlusions and the initial three controls then underwent six months of mating trials. All 17 rabbits were killed. Gross inspection and histologic specimens of their fallopian tubes were obtained. RESULTS: None of the 11 rabbits with fallopian tube occlusion that underwent mating became pregnant. All three control rabbits became pregnant. Histologic study of the occluded fallopian tubes demonstrated long-segment tubal wall fibrosis with varying degrees of occlusion. No peritoneal anormalities were identified. The three controls were histologically normal. CONCLUSION: With use of a nonsurgical transcervical coaxial catheter system, MCA can be directly placed into fallopian tubes without difficulty. Unlike the other cyanoacrylates MCA has unique properties that lead to fallopian tube fibrosis and occlusion. Our results demonstrated a 100% nonpregnancy rate. Further investigation may lead to a safer, more convenient, and less expensive form of permanent sterilization.

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Wednesday, March 29. Room 304 Scientific Session 21 Neurointerventional MODERATOR: Tony P. Smith, MD, Durham, NC

Spiral CT Angiography: A New Tool for Evaluation of Carotid Artery Stenosis J. Link, MD, Kiel, Germany J. Brossman, MD M. Grabener, MD S. Mueller-Huelsbeck, MD J.C. Steffens, MD M. Heller, MD PURPOSE: To determine prospectively the use of spiral CT angiography for the evaluation of carotid artery stenosis. MATERIALS AND METHODS: Spiral CT angiography and selective DSA were performed in 46 patients (27 male, 19 female; aged 42-80 years; mean, 63 years) with 82 carotid artery stenoses. The degree of stenosis was determined according to the technique of the NASCET study by measuring maximal stenosis in relation to the postbulbar internal carotid artery. The degree of narrowing was classified in categories: total occlusion (loo%), severe (70% to 99%), moderate (30% to 69%), and mild (0% to 29%) stenosis. RESULTS: In 68 of 82 cases (83%),the classifications of stenosis, as determined with spiral CT angiography and DSA, were the same, resulting in a significant correlation ( r = .95, P = .0001; Spearman rank test). In the mild stenosis group, 13 of 22 cases (59%) were correctly interpreted ( r = .61; P = .0054); in the moderate stenosis group, nine of 11 (82%) ( r =. 77; P = .0143); and in the severe stenosis group, 27 of 30 (90%)( r = 26, P = .0001). Nineteen occlusions showed a correlation of 100% ( r = 1; P = .0001). Calcification was correctly demonstrated by DSA in 56% of cases. CONCLUSION: Spiral CT angiography is a new tool to evaluate carotid artery stenosis and has a high correlation with DSA. Its advantage over DSA is its superior delineation of calcified plaques. Acute Thrombolytic Therapy in Stroke: Technique and Results R.T. Higashida, MD*, San Francisco, CA S.L. Barnwell, MD V.V. Halbach, MD* C.F. Dowd, MD G.B. Hieshima, MD* PURPOSE: Patients presenting with symptoms of acute thromboembolic stroke are now being man-

aged by direct, local fibrinolytic infusion techniques. For acute occlusion of the cerebral vessels, a microcatheter can be guided directly into the clot, and infusion of urokinase can be performed for thrombolysis. MATERIALS AND METHODS: Patients ranged in age from neonatal to 81 years. There were 33 patients, 19 male and 14 female. Twenty-four patients were treated for acute arterial occlusion in 41 vascular territories. Nine patients were treated for an intracerebral dural sinus thrombosis in 10 vascular territories. RESULTS: For direct infusion into occluded arterial segments, there was angiographic evidence of clot lysis with recanalization and improved cerebral perfusion in 33 (80.5%)of 41 vascular territories treated. Clinically, there was neurologic improvement in 15 (62.5%) of 24 cases. Complications related to therapy included hemorrhage in three cases (12.5%) and no clinical improvement in eight (33.3%).Thrombolysis of the venous dural sinus was performed in 10 cases. In seven (70%)of 10 cases there was angiographic evidence of clot lysis with improvement of cortical venous drainage. CONCLUSION: Direct local thrombolytic therapy may be useful for treatment of acute thrombotic occlusion of cerebral vessels. Further clinical studies are indicated to define optimal patient criteria and infusion regimens.

Endovascular Management of Acute Traumatic Vascular Injuries to the Head and Neck: Therapeutic Options R.T. Higashida, MD*, San Francisco, C A V.V. Halbach, MD* * C.F. Dowd, MD * G.B. Hieshima, MD" PURPOSE: Acute traumatic vascular injuries to the head and neck that result in arteriovenous fistulas are often difficult to treat by direct surgical access. This is due to anatomic location, instability of the acutely injured patient, and difficulty in localizing the exact site of injury. MATERIALS AND METHODS: A total of 234 patients have been treated with endovascular techniques for an acute vascular injury. This includes 206 cases of direct carotid cavernous sinus fistulas, seven indirect (dural) fistulas, and 21 vertebral artery fistulas. A variety of devices, including detachable-balloons, liquid tissue adhesives, microcoils, and silk sutures were used with the goal of fistula occlusion and preservation of the parent vessel. RESULTS: In 193 cases (82%), complete occlusion of the traumatic fistula site was achieved. In 41 cases (la%),the carotid or vertebral artery had to

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be occluded by means of endovascular techniques because of extensive vascular injury in 28 cases and subtotal occlusion of the fistula in 13 cases. Complications included transient cerebral ischemia in six cases, pseudoaneurysm formation in five, stroke in five, and peripheral nerve injury in one. CONCLUSION: Endovascular treatment of acute traumatic vascular injuries to the head and neck region can be well managed by interventional techniques. Complete occlusion of the fistula with preservation of the parent artery can be achieved in a high percentage of patients, with acceptably low morbidity.

Preoperative Transarterial Embolization of Spinal Column Neoplasms T.P. Smith, MD, Durham, NC L.L. Gray, MD C.S. Payne, MD E.R. Hudson, MD PURPOSE: To determine the safety and empirical efficacy of vertebral column embolization prior to surgical resection of vascular neoplastic disease. MATERIALS AND METHODS: Twenty embolization procedures were performed in 14 patients with vascular neoplasms of the vertebral column (T-5 to L-5) who presented with symptoms and physical findings referable to the back and lower extremities. All patients underwent selective angiography to determine the degree of vascularity and any arterial supply to the spinal cord (one patient). Arterial embolization ranged from one to six arteries. Provocative testing with 2% lidocaine was performed in six of 20 procedures. Absorbable gelatin was used alone in two cases and polyvinyl alcohol sponge particles with or without adsorbable gelatin in all others. Surgeries ranged from complete vertebrectomy ( n = 9) to debulking and fixation (n = 5). RESULTS: All surgeries were successful, and none were deemed incomplete or terminated due to blood loss. The average blood loss by visual estimates was 2,070 mL (range, 9004,500 mL). Gelatin embolization alone resulted in higher blood loss (average, 3,550 mL) than polyvinyl alcohol embolization (1,700 mL). A single complication, increased leg weakness, occurred in a patient who did not undergo provocative testing. CONCLUSION: Vertebral column embolization prior to surgical resection is empirically successful, especially with more distal embolic agents. Embolization is a safe procedure, but provocative testing is warranted.

Diagnosis and Management of Spinal Dural Arteriovenous Fistulas D. W. Larsen, Jr, MD, San Francisco, C A V.V. Halbach, MD* * R.T. Higashida, MD* * C.F. Dowd, MD * C.G. McDougall, MD G.B. Hieshima, MD* PURPOSE: To present the authors' experience in 31 patients with spinal dural arteriovenous fistulas (AVFs). MATERIALS AND METHODS: Thirty-one patients (24 male, seven female; average age, 60 years; range, 28-80 years) with a diagnosis of spinal dural AVF were reviewed. The average time to diagnosis was 2.2 years. RESULTS: Spinal dural AVFs were located in the cervical region ( n = 21, thoracic ( n = 211, lumbar ( n = 4), and sacral ( n = 4) regions. Eighteen patients were treated with endovascular occlusion, including five who underwent embolization preoperatively. Twenty patients were treated with surgical resection, including three after failed embolization. Three patients treated primarily with liquid adhesives demonstrated persistent filling from pedicles that could not be embolized and were treated surgically. Of 11 patients occluded with endovascular therapy alone, all but two have had clinical improvement. Of 13 patients treated solely with surgery, all but four have had improvement. Five of seven patients treated with preoperative embolization and surgery demonstrated improvement, and two demonstrated no change in symptoms. No patients in any treatment group demonstrated permanent worsening of symptoms. CONCLUSION: Spinal dural AVFs may present with an insidious onset of nonspecific symptoms, which may delay the definitive diagnosis. Endovascular occlusion and surgical obliteration of the fistula appear to be equally effective methods of treatment. The degree of clinical improvement may be affected by the duration of symptoms prior to treatment.

US-guided Percutaneous Lumbar Anterior Diskectomy with Use of a Peritoneal Fluid Infusion G.M. Onik, MD*, Orlando, FL PURPOSE: The purpose of this series of animal experiments was to show the feasibility of removing a lumbar disk through a percutaneous anterior transabdominal approach. MATERIALS AND METHODS: Under fluoroscopic conrol, an 18-gauge Varees-type needle was intro-

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duced into the pig's peritoneal cavity, and 1 L of saline was then infused with the pig in the reverse Trendelenberg position. With use of a Seldinger technique and under US guidance, a nucleotome was placed within the L-5 to S-1 disk and the disk was aspirated with an automated nucleotome. RESULTS: Four pigs successfully underwent disk aspiration with this technique. The fluid infused into the peritoneal cavity floated the bowel out of the pelvis, clearing a path for the instruments and creating an acoustic window between the anterior abdominal wall and the anterior spine. US allowed passage of the instruments safely between the pelvic vessels into the disk. No complications were noted. CONCLUSION: US-guided percutaneous anterior diskectomy with fluid infusion is a feasible procedure. The implications for the treatment of herniated lumbar disks will be discussed.

Thursday, March 30 Room 315 Scientific Session 22 Stents: Technical Advances MODERATOR:

Anthony C. Venbrux, MD, Baltimore,

MD

Feasibility Study of a Polyurethane/Siliconecovered Hexagonal Cell Nitinol Intravascular Stent: Effects on the Aorta and Vena Cava in the Swine Model E.D. Schwartz, BA, Baltimore, MD A.C. Venbrux, MD W. Watson, BS M.A. Samphilipo, Jr, B S C.A. Magee, BS J.L. Olson, MD, et a1 PURPOSE: To compare the histopathologic and radiologic effects of a polyurethanelsilicone-covered nitin01 stent constructed of two different wire gauges in the aorta and IVC of the swine. MATERIALS AND METHODS: Stents, constructed of either 0.010-inch- or 0.014-inch-diameter nitinol wire, were covered with Cardiothane 51, a polyurethanelsilicone polymer. Stents were placed in the aorta and IVC with 7- and 9-F (inner diameter) vascular sheaths. Five animals were not given anticoagulants and one was given heparin and warfarin. After a follow-up contrast study a t 1, 1'12, 2, 3, or 4 weeks, five animals were killed. One died of anesthetic complications. Stented vessels were fixed in formalin for histopathologic analysis.

RESULTS: Despite successful stent placement and expansion, follow-up contrast studies demonstrated luminal narrowing of the aorta and IVC a t stent placement sites, with complete IVC oclusion in one pig. In two animals, the aortic lumen enlarged at stent sites. The covering occluded vessel side branches. At necropsy, gross examination of four animals demonstrated thrombus on the luminal surface of all stents. In the animal receiving anticoagulation, no thrombus was visible after 9 days. CONCLUSION: Deployment of polyurethanelsilicone covered nitinol stents is feasible. Thrombus formation remains problematic. Arterial Stent-induced Hyperplasia: Early in Vivo Comparison of Polymer-coatedand Uncoated Metallic Stents A.B. Fontaine, MD, Columbus, OH J. Clay, MS K. Koelling, PhD D.G. Spigos, MD J. Cearlock, MD PURPOSE: The evaluation of short-term (4-week) biocompatibility (neointimal hyperplasia/possible inflammatory reaction) of polymer coated versus bare metallic vascular stents in an overdilation porcine model. MATERIALS AND METHODS: Vascular stents ( n = lo), five coated with polyetherurethane (block copolymer) and five bare tantalum, were balloon overdilated (approximately 25% - 66% overdilation) in 10 renal arteries of five swine. Stented arterial segments were harvested after 4 weeks and evaluated with histologic techniques. RESULTS: All coated stents were patent at followup. Histopathologic study demonstrated that a thicker neointima had developed within uncoated stents versus coated stents ( P < .05); there was no sign of inflammatory reaction. Coated stents had an average neointimal thickness of 235 pm + 98 (range, 19-469 pm); uncoated stents had an average of 1,169 pm + 366 (341-2,170 pm). CONCLUSION: Polyetherurethane (block copolymerl-coated stents developed a thinner neointima than bare tantalum stents. There was no evidence of inflammatory reaction. The specific polymer used in this experiment improves the short-term biocompatibility of tantalum stents, when compared in the overdilation porcine model.

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Gel Paving of Intraarterial Stents in Vivo Reduces Stent and Adjacent Arterial Wall Thrombogenicity M.J. Slepian, MD*, Tucson, AZ F. Khosraui, MS* S.P. Massia, PhD* M. Kierus, BS* G.S. Khera, MD* J.A. Hubbell, PhD* PURPOSE: We previously described "gel paving," a form of polymer paving in which a thin coating layer of hydrogel may be formed on arterial endoluminal surfaces via photopolymerization in situ. Endoluminal hydrogels have been demonstrated to be thromboprotective, functioning as physical barrier layers limiting platelet deposition and thrombus formation. In this study we examined whether in situ photopolymerization of a hydrogel paving layer directly over a stent and adjacent arterial wall, immediately after stent deployment, would reduce the thrombogenicity of the stented artery in vivo. MATERIALS AND METHODS: Pigs ( n = 4) were pretreated with aspirin (325 mg once daily for 2 days), heparinized (intravenous, ACT > 300 sec), and subjected to bilateral femoral artery angioplasty. Palmaz stents (1-cm length) were deployed bilaterally in the post angioplasty femoral arteries (one stent per vessel). In random fashion thin hydrogel paving layers (100-150 ym) were photopolymerized (514 nm, 30 sec) in situ within one stented femoral artery per pig, covering a 3.5-cm segment encompassing the stent, with the contralateral unpaved stented artery serving as control. Following 1 hour of blood flow exposure, bilateral femorals were fixed, excised, and examined via stereomicroscopy and scanning electron microscopy. Gross thrombus and the number of platelets adherent to the arterial subintima in the stented zone (five fields per specimen) were assessed. RESULTS: Gross thrombus was not detected within the stent or the adjacent arterial zone in any of the four gel-paved stented femoral arteries. In control unpaved stented arteries, thrombus, ranging from patchy to near occlusive, was seen in three of four femorals. In gel-paved stented arteries 2.08 platelets + 2.13 per x 3,000 subintimal field were detected versus 64.75 platelets f 17.3 in unpaved stented femoral control arteries ( P < .005). CONCLUSION: In situ photopolymerization of thin PEG-lactide hydrogel paving layers directly over stents and adjacent arterial wall, immediately following stent deployment, is effective is reducing the thrombogenicity of stented arterial segments in vivo. Further development of this approach may

lead to a viable adjunctive physical method for limiting clinical stent thrombosis.

Drug-Polymer-coated Intravascular Stents: Results in an Atherogenic Swine Model E.K. Nishimura, MD, Los Angeles, CA H. Yoon, MD, PhD S.C. Goodwin, MD PURPOSE: To evaluate the efficacy of drug-polymer-coated intravascular stents in the reduction of myointimal hyperplasia (MIH). MATERIALS AND METHODS: Two types of heparin-coated Palmaz stents were devised: heparin covalently bound to a polyethylene oxide (Hp-PEO) tether and heparin mixed into ethylene vinyl acetate (Hp-EVA)for slow drug release. Stents were also coated with EVA alone. Polymer-coated stents and uncoated controls were deployed in the external iliac arteries following extensive endothelial injury in 16 swine. Swine were maintained on an atherogenic diet and examined with angiography a t 6 and 12 weeks. The stented segments were then harvested for histopathologic analysis. RESULTS: Both types of heparin-coated stents resulted in increased MIH compared with the contralateral uncoated stents. At 12 weeks, the percentage luminal diameter stenosis was 36% for Hp-PEO stents versus 26% for uncoated stents ( P < .05). For Hp-EVA stents, the average stenosis was 48% versus 14% for uncoated controls ( P < .05). However, Hp-EVA stents fared better than EVA stents (not significant). CONCLUSION: Our results suggest that neither heparin bound to nor heparin slowly released from polymer-coated stents reduces MIH following significant endothelial injury in an atherogenic swine model.

Endovascular Grafting in Aortocaval Fistula: A Percutaneous Animal Model F.P. Boudghene, MD, Paris, France M.R. Sapoval, MD J.R. Bigot, MD J. Michel, PhD PURPOSE: All the models and procedures currently used to test the blood tightness and thrombogenicity of endografts require surgery. We have developed a percutaneous model of aortocaval fistula (ACF) to allow nonsurgical experimentation with endovascular grafting. MATERIALS AND METHODS: An ACF was created percutaneously in eight sheep. With a combined venous and arterial femoral approach, angioplasty balloons were inserted to occlude the

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infrarenal aorta and IVC. The IVC was punctured through the lateral aortic wall with a transjugular liver biopsy needle. The fistulous tract was then dilated with a n 8-mm balloon and the animal was heparinized. Two weeks later, a 10 x 30-mm Cragg Endopro stent was inserted in the aorta a t the level of the fistula with a percutaneous femoral approach. RESULTS: ACFs were successfully created in all animals, with rapid dye shunt through the fistula and a 20% increase in heart pulsations. At 2 weeks, in all cases, a control angiogram showed a patent ACF and stent implantation excluded the fistula. Angiographic and pathologic controls a t 3 months demonstrated normal aortic patency and remaining exclusion of the fistulas. CONCLUSION: ACFs were efficiently treated by endovascular grafting of the aorta. Both the animal model and the procedures were performed percutaneously.

New Intraluminal Stent Graft for Aortic Aneurysms D. Paucnik, MD, PhD, Portland, OR F.S. Keller, MD J. Rosch, MD* H. Shim, MD, PhD H.A. Timmermans, B S A X B.T. Uchida, B S X PURPOSE: To evaluate new straight and curved endoluminal stent grafts for exclusion of aortic aneurysm (AA) with a smaller delivery system. MATERIALS AND METHODS: Abdominal AAs were created in 10 dogs by implantation of straight sacciform Dacron tubing 3-12 cm long and 10-26 mm in diameter. In two dogs, a curved AA was created. A new square stent was used in five animals, a combination of square stents and Z stents in six, and Z stents in one. They were 11-27 mm in diameter and covered with Dacron. Aortograms were obtained before and after stent graft placement, and animals were killed 3-4 hours later. RESULTS: Stent graft deployment was successful in all cases. Aneurysmal exclusion was achieved in 11 dogs immediately after device placement, and in one case (covered square stents 27 mm in diameter) 90 minutes after deployment. Stent grafts were introduced through sheaths from 10 to 20 F, depending on their diameter. CONCLUSION: The tested stent grafts resulted in almost immediate exclusion and thrombosis of AAs.

Thursday, March 30 Room 316 Scientific Session 23 Central Venous Access MODERATOR:

John F. Cardella, MD, Hershey, PA

Cumulative Experience with 1,194 Central Catheters Peripherally Inserted with Different Techniques at a Single Institution J.F. Cardella, MD, Hershey, PA N. Bacci, CRNI K. Cardella, RN, B S N P.S. Fox, MD J.H. Post, MD PURPOSE: The peripherally inserted central catheters (PICCs) of four of six major suppliers have been tested to find the "perfect" PICC. The PICCs were studied by a team of cardiovascular-interventional (CVI) radiologists and specially trained PICC nurses, in both bedside and fluoroscopically guided insertions in the same patient population a t the same institution. We report on our experience and findings with regard to the four tested PICCs and on the properties of the "ideal" PICC. MATERIALS AND METHODS: Initially, bedside insertions were performed by nurses, residents, and attending physicians; low technical success allowed CVI radiology (CVIR) to supplant bedside insertions. Recently, the desire to lower cost and to substitute PICCs for inpatient peripheral intravenous (IV) lines has rekindled interest in bedside insertions, which are now limited to three specially trained nurses. Difficult initial insertions, bedside failures, and problematic PICCs are still referred to CVIR. For bedside insertions, a palpatory throughthe-needle technique is used. A venographic-fluoroscopic direct puncture and sheath technique is used for CVIR insertions. PICCs from Gesco International ( n = 7701, Cook Critical ( n = 305), HDC Corp ( n = 1071, and Luther Medical, Inc, ( n = 12) were tested; PICCs from Bard Access Systems (due to high cost) and from Vygon Corp (a newcomer to the field) were not tested. RESULTS: In 56 months, 1,194 PICCs were inserted in 947 patients, 364 a t the bedside and 830 in CVIR. Dual-lumen PICCs accounted for 64.5% and 63.2% of bedside and CVI insertions, respectively; single-lumen PICCs, 35.5% and 36.8%. The male-female ratio was 43.9%:56.1%, with a mean patient age of 54.7 years. The previous bedside technical success rate of 74% has improved to 90%; the CVIR technical success rate has remained a t

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98.6%. Dwell time has decreased from 72.7 days to 26 days (due to PICCs replacing short-term peripheral IV lines). Procedural complications remain very low. Device failures, including hub cracks, hub separations, twisted/broken catheters, needle punctures, inadvertent removals, and occlusions due to improper flushing, continue to be problematic. Depending on PICC indication and length of therapy, between 18% and 28% of patients will require more than one PICC to complete therapy. CONCLUSION: The ideal PICC has not yet been developed; greater hub strength and "graspability," better hub-catheter transition zone, and better radiopacity are sorely needed. Four vendors' PICCs were tested; the strengths and weaknesses of each device will be discussed. Bedside insertions were cost-effective and technically successful when done by specially trained nurses. Uncontrolled insertion of PICCs by anyone on the health care team is ill advised. CVI radiologists remain the "experts" in difficult initial insertions and in all manner of PICC salvage and exchange.

134 2:OO PM Efficacy and Economic Benefits of Radiologic Guidance for Peripherally Inserted Central Catheters T.P. Bocchini, MD, S t Louis, MO M. Sundaram, MD M.K. Wolverson, MD PURPOSE: Comparison of the efficacy, indications, complications, and cost-effectiveness of radiologic placement of peripherally inserted central catheters (PICCs) in patients with thrombosed antecubital veins versus surgical placement of Hickman catheters. MATERIALS AND METHODS: Eighty-five consecutive patients in whom PICCs were placed, with guidance by fluoroscopy and antegrade or retrograde venography, were compared with 85 consecutive patients receiving surgically placed Hickman catheters. Follow-up was obtained in all patients until the catheter was removed. A cost accounting evaluation was made between the techniques. RESULTS: PICC placement was successful in 100% of patients. Therapy was completed with a single catheter in 98% of PICC patients versus 93% of Hickman patients. The PICC group had two complications, the Hickman group had 12. The total duration of catheterization was 2,255 days for the PICC group (average, 26 days; longest, 150 days) and 7,817 days for the Hickman group (average, 92 days; longest, 391 days). Hickman catheters remained in place longer for all indications including antibiotics (61 vs 21 days on average) and chemo-

therapy (128 vs 44 days). Cost comparison studies will be described, demonstrating significant cost savings with PICCs. CONCLUSION: Radiologic placement of PICCs in a select subset of patients requiring less than 5 months of access is a reliable and efficacious technique with significant cost savings over surgically placed Hickman catheters.

Fluoroscopically Guided Subclavian Vein Access W.E. Campbell, Jr, MD, Chapel Hill, NC M.A. Mauro, MD PURPOSE: To determine whether the subclavian vein (SCV)/first rib anatomic relationship is sufficiently constant to allow safe and reproducible fluoroscopically guided SCV puncture. MATERIALS AND METHODS: Forty-four SCV venograms were obtained in 42 consecutive adult patients. The position and width of the SCV crossing over the first rib were recorded by using radial coordinates. Based on this anatomic study, 42 SCV access procedures were performed with use of the first rib as a fluoroscopic marker. Technical success, complications, number of 21-gauge needle passes, and the patient's body habitus were recorded. RESULTS: The mean angular position of the SCVI first rib crossover was 94.9" (SD, 7.42"). The mean radial width of the SCV was 14.9" (SD, 3.1"). Twenty-five of 44 (60%) lay within the 90"-99" segment, and 36 of 44 (82%)within the 85"-104" segment. The rate of technical success in accessing the SCV was 100% (42142). Two minor complications involved subclavian artery puncture with the 21gauge needle without sequelae. The mean number of needle passes required was 2.86. CONCLUSION: The SCV is reliably constant in its relation to the first rib. The first rib alone provides a reliable fluoroscopic marker for safe SCV access without requiring US guidance or peripheral contrast medium administration.

Implantable Chest Wall Venous Infusion Ports: Follow-up of 154 Radiologically Guided Placements M. Rosenblatt, MD, New Haven, CT T. Lovett, R N J.S. Pollak, MD K. W. Dickey, MD T.K. Egglin, MD PURPOSE: To determine the efficacy of radiologically assisted placement of chest wall infusion ports, we reviewed our experience with placement, management, and outcome.

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MATERIALS AND METHODS: Over 21 months, 154 infusion ports were placed in 152 patients. One hundred twenty-eight double-lumen and 26 singlelumen ports were implanted via the subclavian vein (n = 152) or the IVC (n = 2). Eight patients (5%) had undergone unsuccessful surgical attempts. Medical records were reviewed, and patient interviews were conducted to assess port function and acute (30-day) and late complications. Follow-up was incomplete in 14 patients (9%). RESULTS: All attempts at port placement were successful. After 27,245 days of cumulative followup, the overall complication rate was 0.7% per 1,000 access days. Acute complications included pneumothorax (n = 2), hematoma (n = I), symptomatic venous thrombosis (n = I), skin necrosis (n = I), asymptomatic catheter infection (n = 21, and port malfunction (n = 4). Ten (6%) late complications included symptomatic venous thrombosis (n = 4), catheter sepsis (n = 51, and skin necrosis (n = 1). Late port malfunction occurred in nine patients. Of the 30 complications, 19 required aggressive intervention (fibrin sheath stripping, catheter repositioning, chest tube, thrombolysis, port removal). Fourteen were managed by our service. CONCLUSION: Placement of infusion ports by the interventional radiologist is safe and efficacious and offers several advantages over surgical placement.

Long-term Percutaneous Peritoneal Port Catheters for Chemotherapy Infusion R.J. Killian, MD, Washington, DC S.V. Lossefj MD K.H. Barth, MD PURPOSE: The authors examined the tolerance and complications of intraperitoneal port access catheters placed percutaneously for long-term administration of BB94, an experimental chemotherapeutic agent that can be administered only via the intraperitoneal route. MATERIALS AND METHODS: Seven patients with various advanced malignancies underwent percutaneous peritoneal port placement. Eighteen-gauge blunt needle puncture was performed lateral to the rectus sheath (as determined with US) under fluoroscopic guidance. A 7-F Silastic catheter was advanced into the pelvic peritoneal space and threaded subcutaneously to a port pouch over the lower rib cage. RESULTS: Catheter insertion was successful in all cases. The gallbladder was inadvertently punctured in one patient and immediately evacuated to avoid subsequent bile leak. This patient had no further complications. The dwelling time of the catheters

was 6-92 days at the time of writing. One patient died after 74 days. In two patients the catheter was removed at 41 and 65 davs because of systemic complications of chemotherapy, although the catheter remained functional. All catheters remained patent, and four are still in use. CONCLUSION: Percutaneously placed intraperitoneal port catheters provide a closed system for administration of intraperitoneal chemotherapy agents, reducing the potential of peritonitis. They appear to be well tolerated in this study group.

Percutaneous Fibrin Sheath Stripping of Failing Central Venous Catheters Z.J. Haskal, MD, Philadelphia, PA V.H. Leen, MD M.C. Soulen, MD R.A. Baum, MD R.D. ShlanskyGoldberg, MD D.C. Redd, MD, et a1 PURPOSE: Long-term central venous catheters are prone to significant dysfunction due to fibrin accumulation around the catheter tips. We assessed the efficacy of transvenous snare removal of fibrin to prolong catheter function. MATERIALS AND METHODS: Twenty-three procedures were performed in 17 patients (14 hemodialysis Permacaths, two Hickman catheters, one Port-acath). Technical success was judged by means of venography and the ability to infuse and aspirate catheters. Durable efficacy was indicated by improvement in hemodialysis and restoration of patency in nondialysis catheters. RESULTS: Twenty-one of 23 procedures were performed successfully. In two cases residual material remained despite repeated stripping. The mean rate of blood processing by hemodialysis increased from 21.7 to 27.6 L/h after treatment, remaining below target levels for each patient. After 18 of 20 interventions, this increase disappeared after four dialysis sessions. Within a mean 14 days of stripping (range, 1-40), five catheters were replaced and 13 received urokinase therapy. Two of three nondialysis catheters successfully treated have remained patent a t 6 and 16 weeks of follow-up. CONCLUSION: Percutaneous fibrin removal has no durable benefit in improving hemodialysis catheter function. Early experience suggests better efficacy in catheters not requiring sustained high flow rates.

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Thursday, March 30 Room 305 Scientific Session 24 Biliary Interventions MODERATOR:

Franklin J. Miller Jr., MD, Salt Lake

City, UT

Benign Biliary Obstruction: Long-term Results of Metallic Z Stents as the Definitive Treatment R. Uflacker, MD, Charleston, SC I. Vujic, MD M.A. Chita, MD PURPOSE: To analyze clinical findings and followup in patients with benign biliary obstruction treated by self-expandable metallic Z stents. MATERIALS AND METHODS: Twenty-one patients with benign biliary obstruction treated with Z stents were prospectively studied. Biliary obstruction was caused by sclerosing cholangitis ( n = 21, laparoscopic cholecystectomy ( n = 4), conventional cholecystectomy ( n = 31, choledochojejunostomy ( n = l o ) , choledochoduodenostomy ( n = I), and anatomical variation and recurrent cholecystitis ( n = 1). All stents were introduced percutaneously. Five patients needed stone treatment in addition to cholangioplasty and stent placement. RESULTS: Stent placement was successful in all patients. Stent occlusion occurred in four patients (19%),a t 3, 7 , 12, and 25 months after insertion. Recurrent cholangitis was observed in eight patients (38%).Follow-up time ranged from 10 to 60 months. CONCLUSION: Self-expandable metallic Z stents are effective as definitive treatment for benign biliary obstruction. 140 2:00 PM Feasibility of Temporary Placement of a Biliary Balloon-expandableNitinol Stent R.D. Shlansky-Goldberg, MD J.L. Groffsky, MD, Philadelphia, PA M.M. Levy, MD M.C. Soulen, MD PURPOSE: The aim of this study is to investigate the feasibility of deploying and retrieving a novel temporary biliary stent made from a slotted balloonexpandable tube of nitinol with thermal memory in the nonexpanded shape. MATERIALS AND METHODS: In two conventional swine, a 5-F T tube was surgically placed within the common hepatic duct and a distal stricture pro-

duced in the common bile duct with a 4-0 Vicryl suture. After 6 weeks allowing for tract formation and dissolution of the Vicryl suture, the strictures were stented to 8 mm. The first pig underwent immediate retrieval of the stent, while the stent remained in place for 24 hours in the second pig. For removal, a circumferentially perforated 8-F catheter was introduced into the middle of the stent and saline of increasing temperatures from 57" to 100°C was injected to recover the stent. RESULTS: Both stents could be removed but required hotter saline than the design temperature, most likely due to thermal loss within the delivery system. The 24-hour stent did not completely return to its predeployment size as easily as the first stent, due to debris in the lattice work. CONCLUSION: Temporary stent placement is feasible with use of a heat-recoverable stent. Issues regarding recoverability and thermal injury need to be investigated further.

Closure of Biliary Fistulas with Metal Coils H. Bjarnason, MD, Minneapolis, MN G.K. Nazarian, MD T.V. Myers, MD H. Ferral, MD W.R. Austin, MD D.W. Hunter, MD, et a1 PURPOSE: To describe the use of metal coils to close biliary fistulas, mainly in liver transplant recipients. MATERIALS AND METHODS: Twelve patients have been treated: eleven with a liver transplant Ttube tract leak into the peritoneal cavity and one patient with a fistula after cholecystectomy. The liver transplant T-tube tracts were embolized either immediately after the removal of the T tube or, more commonly, after conservative treatment with angiographic drainage catheters had failed. The patient with a leak after cholecystectomy had the fistula occluded by coils after unsuccessful conservative therapy. At least two coils were placed in the tract as close to the entry into the biliary system as possible. A drainage catheter was left in the tract "external" to the coils. RESULTS: Fistula closure was successful in all cases usually within minutes and, a t the longest, within 2 or 3 days. Conservative treatment had usually been tried for 2-4 weeks or longer. CONCLUSION: The use of metal coils to close persistent biliary fistulas is very successful. There were no complications related to the procedure. The method is recommended as the primary treatment when persistent biliary leakage is identified.

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142 2:30 PM Chronic Biliary Sludge Syndrome: Experience in Adult Liver Transplant Recipients over a 5year Period A.C. Loesberg, MD, Chicago, IL C.A. Hackworth, MD J.A. Leefj MD PURPOSE: Chronic biliary sludge or casts are a rare complication after liver transplantation. We report our experience with biliary intervention and the clinical outcome in these patients. MATERIALS AND METHODS: Over a 5-year period, 180 patients received 220 liver transplants at our institution. Fifteen patients were diagnosed with chronic biliary syndrome by means of percutaneous transhepatic cholangiography, T-tube cholangiography, and endoscopic retrograde cholangiopancreatography. Percutaneous interventional biliary procedures were performed on these patients during multiple visits. Cholangiograms, operative reports, and medical records were reviewed. RESULTS: Of the 15 patients studied, 13 required long-term biliary drainage. Of these, five patients required repeated transplantation despite long-term drainage and multiple percutaneous interventional procedures and six continue to undergo chronic external catheter drainage, awaiting retransplantion. Four patients continued to have biliary sludging despite surgical revision of the biliary-enterostomy. Only two patients improved with biliary intervention to allow removal of the drainage catheters. CONCLUSION: Chronic biliary sludge is an ominous finding in the posttransplantation period. Despite biliary diversion, percutaneous intervention, and surgical bile duct revision, these patients have a poor outcome, often requiring long-term catheter placement and repeated liver transplantation. 143 2:45 PM Experimental Cholecystogastrostomy and Cholecystojejunostomy with Magnet Compression C. Cope, MD, Philadelphia, PA PURPOSE: To asses the efficacy of rare earth magnets for creating cholecystogastrostomies (CGs) and cholecystojejunostomies (CJs) in swine. MATERIALS AND METHODS: Rectangular and disk magnets of various configuration and strength were inserted in nine pigs. They were implanted surgically within the gallbladder and jejunum and perorally in the stomach, and then coupled to form four CGs and five CJs. Gross and histologic examinations of the resulting anastomoses were performed 9-15 days postoperatively. RESULTS: All anastomoses showed good adhesion, with no gross evidence of leakage or inflammation.

Anastomoses were fully patent in four CGs, partially patent in two CGs and one CJ, and not formed in two CGs. Best results were noted with jacketed disk magnets with cutting edges and a 500-600-g pull. CONCLUSION: Patent leakproof cholecystoenteric anastomoses were created with magnets in seven of nine pigs within 9-14 days. This technique may have interventional clinical applications.

Peripheral Biliary Diversion with Hepaticogastrostomy for Treatment of Malignant Biliary Obstruction: An Alternative Therapeutic Approach G. Soulez, MD, Montreal, Que M. Gagner, MD E. Therasse, MD E. Deslandres, MD A. Pomp, MD P. Robillard, MD PURPOSE: Percutaneous transhepatic stent placement for the palliation of malignant biliary obstruction is limited by reocclusion of the stent. A new technique of peripheral biliary diversion anastomosing segment I1 bile duct to the lesser curvature of the stomach is reported. MATERIALS AND METHODS: Sixteen patients with unresectable biliary neoplasms were treated. A transhepatic perforation of the left lobe of the liver and the lesser curvature of the stomach was achieved under fluoroscopic, endoscopic, and laparoscopic guidance in 14 patients and without laparoscopy in two. The anastomosis between the biliary tree and the stomach was secured with a gastrostomy tube positioned across the tract. Two weeks later the tube was removed and the patency of the tract was maintained with Gianturco metallic stents. RESULTS: Drainage was adequate in all patients. Only one reobstruction was observed 3 months after the procedure. Six patients are still alive with a mean follow-up of 7 months (range, 1-15 months). Seven patients died after 5 weeks to 9 months (mean survival, 6 months). Three patients with a poor general condition died within 1 month (7, 17, and 21 days). One cholangitis episode and one subcapsular hematoma of the liver were observed in two patients. CONCLUSION: This peripheral diversion could provide good long-term patency. It could be indicated for patients with a long survival expectancy.

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Thursday, March 30 Room 304 Scientific Session 25 Embolotherapy MODERATOR:

Anne C. Roberts, MD, San Diego, CA

Usefulness of Microcatheter Embolization for Treatment of Traumatic Arterial Injuries D.L. Robinson, MD, Los Angeles, CA G.L. Peters, MD S.E. Hanks, MD D.S. Harrell, MD C.S. Patton, MD * M.D. Katz, MD PURPOSE: The authors report their experience with embolization of arterial injuries secondary to penetrating, blunt, and iatrogenic trauma, using a coaxial microcatheter delivery system. MATERIALS AND METHODS: From 1989 to 1994, 61 patients with arterial injuries were retrospectively studied. All patients underwent therapeutic microcatheter embolization with microcoils andlor Gelfoam pledgets and were followed up thereafter for an average of 89 days. The sites of injury were the extremities in 23, the liver in 17, the pelvis in nine, the kidney in seven, the subclavian branches in four, the viscera in three, and the face in one. Pseudoaneurysms were present in 37, extravasation in 21, and arteriovenous fistulas in 11. RESULTS: In 59 of 61 patients (97%),arterial injuries were successfully treated with microcatheter embolization alone. Three of these patients required two embolization procedures. In two patients microcatheter embolization failed and surgical intervention was required. Procedural complications included one arterial dissection, one catheter-related thromboembolism, and one nontarget embolization. These were either asymptomatic or successfully treated by percutaneous means. CONCLUSION: Microcatheter embolization is a safe and effective means for treating traumatic arterial lesions. The advantages of the coaxial microcatheter system include access to higher-order or smaller spasm-prone arteries; closer access to the site of arterial injury, decreasing the chance of distal reconstitution; and superselective embolization in parenchymal organs, allowing for maximal sparing of uninvolved tissue.

146 2:OO PM Treatment of Life-threatening Pelvic Hemorrhage with Transcatheter Embolization D.J. Roach, MD, Tucson, AZ S.H. Smyth, MD M.S. Asay, MD J.T. Ruth, MD G.D. Pond, MD PURPOSE: Our experience using embolization for control of pelvic hemorrhage is summarized. MATERIALS AND METHODS: Forty-six patients with massive pelvic hemorrhage were referred for angiography and possible embolization (42 with pelvic trauma, three with vaginal hemorrhage, and one with spontaneous hemorrhage). RESULTS: Of the 46 who underwent arteriography, 34 (74%)underwent embolization. Active hemorrhage andlor significant arterial injury was seen in 28 of the 34 treated (82%). Six (18%) had no obvious arterial injury but were embolized empirically. Twenty-three patients survived (68%). Many stabilized immediately after embolization. Three had recurrent hemorrhage due to an associated coagulopathy and were reembolized without further hemorrhage. There were 11 deaths (32%), 10 in spite of technically successful embolization (multisystem failure). One patient died 2 hours after the arteriogram revealed vascular injury but no active hemorrhage. Embolization was attempted only after the patient returned with recurrent hemorrhage. The patient exsanguinated prior to completion of the procedure. CONCLUSION: Embolization for pelvic hemorrhage is effective in our experience. We attribute one death to poor judgment, not to a failure of embolization. We advocate embolization of injured arteries whether or not active hemorrhage is identified. Furthermore, complete interruption of flow is mandatory since coagulopathies are common in these cases and may lead to recurrence. 147 2:15~~ Treatment of Penetrating Pelvic Trauma with Transcatheter Embolization Y.H. Park, MD, Los Angeles, C A S.E. Hanks, MD D.S. Harrell, MD M.D. Katz, MD PURPOSE: To retrospectively review pelvic arteriography with therapeutic transcatheter embolization for the treatment of penetrating pelvic trauma. MATERIALS AND METHODS: The departmental records were reviewed for all patients who underwent pelvic arteriography for penetrating pelvic injury between 1984 and 1994. The medical charts and arteriograms for all patients who underwent transcatheter embolization were studied. RESULTS: Two hundred thirty patients underwent arteriography for penetrating pelvic trauma. Evi-

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dence of vascular injury was identified in 41 patients (18%). Transcatheter embolization was performed in 15 patients (7%). The injuries were gunshot wounds in 13, and stab wounds in two. Embolization, with coils andlor Gelfoam, was performed for extravasation in 10, pseudoaneurysm in four, and arteriovenous fistula in two. In 14 of 15 patients (93%), embolization was considered angiographically and clinically successful, although a single patient required two embolization procedures for effective hemorrhage control. One patient exsanguinated on the angiographic table prior to embolization. Clinical success was documented with a mean follow-up of 259 days and median follow-up of 38 days. Only two patients were lost to follow-up. With the exception of the single death, there were no complications directly or indirectly associated with the procedure. CONCLUSION: While transcatheter embolization for blunt pelvic trauma has been widely discussed, the treatment of penetrating pelvic trauma has been largely ignored. Although pelvic arteriography demonstrates arterial injury in only a small percentage of these trauma victims, transcatheter embolization is a highly effective method of treatment.

Endovascular Treatment of Renal Artery Aneurysms with Conventional Microcoils and Guglielmi Detachable Microcoils G.E. Klein, MD, Styria, Austria R. Karaic, MD H.H. Schreyer, MD PURPOSE: Renal arteries are uncommon sites for aneurysms, and true congenital aneurysms are especially rare. Since there is a potential risk of rupture, thrombosis, and infarction, subsequent therapy is mandatory. The purpose of our study was to evaluate the efficacy and safety of endovascular occlusion of the aneurysms. MATERIALS AND METHODS: Nine renal artery aneurysms were occluded selectively by implantation of conventional platinum microcoils in three patients; Guglielmi detachable microcoils were used in six patients. The coils were delivered through a Tracker-18 microcatheter. Before embolization five patients had hypertension, one each had hematuria and infarction, and two were asymptomatic. RESULTS: All aneurysms could be occluded successfully. In two patients a subsegmental infarction occurred, due to the occlusion of a small peripheral renal artery branch. One coil misembolization of a small conventional microcoil occurred without occlusion of the embolized vessel.

CONCLUSION: Selective endovascular occlusion of renal artery aneurysms, even those located in small peripheral branches, is safe and efficient and seems superior to surgical treatment.

Therapeutic Embolization of the Pulmonary Artery with Lipiodol: Experimental Study 2. Yan, MD, Shanghai, People's Rep of China Y. Shao, MD M. Li, MD PURPOSE: Pulmonary metastases have their blood supply mainly from the pulmonary artery. This study was done to investigate changes in pulmonary tissues after embolization of the pulmonary artery with Lipiodol. MATERIALS AND METHODS: Lipiodol was injected into the pulmonary artery in 19 rabbits (0.5 mLIkg). Rabbits were killed on schedule, and lungs were kept for soft-tissue radiography and histologic examination. RESULTS: Soft-tissue radiography revealed that Lipiodol accumulated in pulmonary tissues and small branches of the pulmonary artery immediately after injection, then gradually reduced. Focal Lipiodol was found a t 1month and disappeared within 5 months. Histologically, diffuse inflammatory changes in pulmonary tissues and hyperinflation of residual alveoli were found within a half-day after injection. Lipiodol in large amounts was found in pulmonary tissues. Histiocyte proliferation began from 1 day with obvious reduction of Lipiodol. Lipiodo1 particles were found in plasma of histiocytes. Focal Lipiodol was found a t 3 weeks and inflammation disappeared. The pulmonary tissues were normal a t 2 months, and no Lipiodol was found. CONCLUSION: The response of pulmonary tissues to pulmonary arterial embolization with Lipiodol is a n inflammatory process. Lipiodol accumulated in pulmonary tissues is cleaned by macrophages of histiocytes. Lung may make up for insufficiency of gas exchange by compensatory hyperinflation. Therapeutic embolization of the pulmonary artery with Lipiodol is safe.

Bronchial Arterial Embolization for Hemoptysis: Where to Occlude the Bronchial Artery? N. Tanaka, MD, Mie, Japan K. Yamakado, MD S. Murashima, MD T. Nakagawa, MD K. Nakamura, MD T. Hattori, MD, et a1 PURPOSE: Bronchial arterial embolization (BAE) was performed for control of hemoptysis. A retro-

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spective study was done to evaluate the optimal site for such embolization. MATERIALS AND METHODS: BAE was performed in 27 cases (inflammation in 13, bronchiectasis in four, tumor in four, and idiopathic in six). Two groups of patients were studied. In the first group ( n = 15), a coaxial microcatheter was deeply inserted into the bronchial artery beyond the mediastinal branches and embolotherapy was performed (distal group). In the second group ( n = 121, embolization was done in the proximal part of the bronchial artery (proximal group). Gelatin sponge was used for embolic material in all cases, and steel coils were added in seven cases in the distal and one case in the proximal group. RESULTS: At 1week after BAE, there was no significant difference in hemoptysis control rate between the distal and proximal groups (93.3% vs 83.3%). At 3 months and a t 1year after BAE, however, hemoptysis was significantly controlled in the distal group as compared with the proximal group (92.3% vs 58.3% at 3 months, 80.0% vs 33.3% at 1 year; P < .05). CONCLUSION: Embolization distal to the mediastinal branch is more effective in controlling hemoptysis than that in the proximal part of the bronchial artery.

Thursday, March 30 Room 315 Scientific Session 26 Venous and Renal Stents MODERATOR:

Chet R. Rees, MD, Dallas, TX

Percutaneous Transhepatic Hepatic Venography in Planning Interventional Radiologic Therapy for Budd-Chiari Syndrome M. W. Wilson, MD, San Francisco, CA E. J. Ring, MD J.M. LaBerge, MD R.K. Kerlan, Jr, MD R.L. Gordon, MD PURPOSE: To assess the usefulness of percutaneous transhepatic hepatic venography (PTHV) in planning interventional therapy for Budd-Chiari syndrome. MATERIALS AND METHODS: Five patients with Budd-Chiari syndrome underwent PTHV when transfemoral cavography and hepatic venography failed to demonstrate the abnormality. PTHV was performed by transhepatic insertion of a 22-gauge

Chiba needle a t the midaxillary 10th or 11th intercostal space. Contrast medium was injected on needle withdrawal, identifying venous structures. Eight interventions were performed in total: one urokinase infusion, one balloon thrombectomy, two balloon venoplasties, two hepatic vein stent placements and two TIPS placements. In a sixth patient PTHV revealed unsuspected Budd-Chiari syndrome after an unsuccessful TIPS attempt. RESULTS: PTHV showed a complex spider-web appearance of hepatic vein collaterals, hepatic vein stenosis, or hepatic vein thrombus. The patient undergoing urokinase infusion and thrombectomy has done well for 24 months. Two patients undergoing placement of hepatic vein stents and TIPS have done well for 41 and 12 months, the latter or eventually undergoing orthotopic liver transplantation. One patient undergoing hepatic venoplasty and stent placement has done well for 13 months. One patient undergoing hepatic venoplasty was lost to follow-up. CONCLUSION: PTHV is a useful adjunct to conventional venography in evaluating the level of hepatic vein outflow obstruction and planning interventions in Budd-Chiari syndrome.

152 4:15~~ Idiopathic Budd-Chiari Syndrome: Treatment with Expandable Z Stents S.S. Baijal, MD, Uttar Pradesh, India S. Roy, MD R.V. Phadke, MD S. Kumar, MD PURPOSE: Self-expandable metallic stents have been extensively used in patients with malignant IVC obstruction. The aim of this study was to evaluate their role in the management of idiopathic Budd-Chiari syndrome. MATERIALS AND METHODS: The study group consisted of seven patients (five men, two women; median age, 26 years; range 22-40 years) who presented with prominent abdominal veins and ascites. Preprocedural vena cavography showed complete IVC block in the supra-and intrahepatic segments with at least one patent hepatic vein below the obstruction. The procedure consisted of balloon dilation of the occluded segment followed by placement of multiple indigenously fabricated and modified Z stents. RESULTS: Successful deployment of stents was achieved in all the patients. Immediate postprocedure evaluation revealed a significant ( P < .05) fall in caval pressures and disappearance of collateral channels. Migration of the stents (one proximal, one distal) during the delivery occurred in two patients and was managed by placement of another set of

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stents across the site of the block. The only postprocedure com~licationsoccurred within the first 48 hours when one patient had epistaxis that was managed conservatively and another died, possibly due to pulmonary embolism. The prominent abdominal veins disappeared within 24-36 hours after the procedure in all patients. During the follow-up (median, 10.5 months, range 1-14 months), patients remained asymptomatic with no recurrence of ascites, and investigations revealed a widely patent IVC. CONCLUSION: We suggest that modified Gianturco ex~andablemetallic stents should be considered as one of the primary modes of treatment for idiopathic Budd Chiari syndrome.

Gianturco-RoschZ Stents in Benign Central Venous Obstructions: Results of Long-term Follow-up B.D. Petersen, MD, Portland, OR P.C. Lakin, MD R.E. Barton, MD F.S. Keller, MD R.R. Saxon, MD J. Rosch, MD* PURPOSE: To evaluate the long-term patency of Gianturco-Rijsch Z (GRZ) stents for treatment of symptomatic central venous obstructions of benign origin. MATERIALS AND METHODS: Twenty-six patients with benign obstructions of the SVC, IVC, and/or large branches were treated with percutaneously placed GRZ stents. Obstructions due to postradiation or idiopathic fibrosis, cirrhosis, Budd-Chiari syndrome, trauma, adenopathy, and dialysis arteriovenous fistula (AVF) were followed clinically, with US or venography. Twenty patients received stents for congestive symptoms, and six patients with AVFs received stents for venous hypertension. RESULTS: Congestive symptoms were relieved in all 20 patients. Of these 20, six are alive and asymptomatic at a mean of 41 months (range, 1560 months). Twelve died without symptom recurrence at a mean of 11 months (range, 1-18 months). Two patients required PTA or stent placement (1 and 10 months) to maintain patency up to 40 months. All patients with AVFs had normalization of venous pressures after stent placement. Venous hypertension recurred due to intimal hyperplasia at a mean of 8 months (range, 1-13 months). Eleven procedures (PTA/stent) were performed, resulting in a mean assisted patency of 28 months (range, 12-57 months). No clinically significant complications occurred. CONCLUSION: GRZ stents are effective devices for treatment of central venous obstructions and demonstrate long-term patency.

Superior Vena Cava Syndrome: Treatment with Endoluminal Stents S.T. Kee, MB, Stanford, CA U.R. Nyman, MD C.P. Semba, MD M.D. Dake, MD G.K. Lee, B S PURPOSE: To evaluate the treatment of superior vena cava (SVC) syndrome with endoluminal stents. MATERIALS AND METHODS: Fifty-two patients with SVC syndrome (29 male, 23 female; mean age, 58.1 years) underwent recanalization of the SVC and placement of endoluminal stents. Thirty-five had underlying malignancies, and 17 had nonmalignant causes. Patients underwent bilateral arm venography demonstrating complete SVC occlusion (66%) or high-grade (> 95%) stenosis (34%). Recanalization included thrombolysis and/or balloon angioplasty and stent placement. RESULTS: Initial recanalization of the SVC (residual stenosis < 30%)was achieved in 51 of the 52 patients (98%). Recanalization was unsuccessful in one patient, who suffered a fatal pulmonary embolus. One other patient died of unknown cause in under 24 hours. There were no other major complications. Follow-up ranged from 2 to 48 months (mean, 18 months). Of the patients with malignancies, 18 patients died free of symptoms of SVC syndrome (mean survival after stent placement, 6.3 months). Of the remaining 17 patients with malignancies, the current primary patency rate of the stents is 76%, and the secondary patency rate is 96%. The 17 patients with nonmalignant causes are still undergoing continued follow-up. CONCLUSION: Treatment of SVC syndrome can be achieved with endoluminal stents.

Placement of a Palmaz Stent in the Renal Artery: A Single Center Experience M. Henry, MD, Essey Les Nancy, France M. Amor, MD I. Henry, MD G. Ethevenot, MD B. Mentre, MD M. Allaoui, MD PURPOSE: To evaluate the role of percutaneous stent placement in the treatment of renal artery lesions after failure of a balloon angioplasty. MATERIALS AND METHODS: Balloon-expandable Palmaz stents were placed in 64 renal arteries of 59 patients with hypertension resistant to therapy ( n = 59) and renal dysfunction (n = 10) with atheromatous ( n = 55), fibromuscular ( n = 3), or Takayasu ( n = 1)diseases. Five patients had bilateral lesions, and two had a solitary kidney. Indications included ostial lesions ( n = 341, restenoses ( n = 20), and unsatisfactory balloon angioplasty results ( n = 10).

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The mean lesions length was 11.4 cm ? 1.1 (range 5-20 cm). RESULTS: Immediate technical success was achieved in 100%. The mean lesion diameter after stent placement was 6.15 mm 2 0.2. Two major complications occurred: one acute thrombosis cured by fibrinolysis and one arterial rupture requiring surgery. Six-month angiographic follow-up was performed in all eligible patients ( n = 54) and showed restenosis in five (9.2%), successfully treated by a new angioplasty. Hypertension was cured in 10 of 54 patients (la%),improved in 32 of 54 (59%),and unchanged in 12 of 54 (23%). Renal dysfunction was improved in two of 10 (20%) and unchanged in eight of 10 (80%). The primary patency at 30 months was 79%; the secondary patency rate, 92%. CONCLUSION: Renal artery stent placement seems to be safe and effective and an alternative to surgical revascularization, especially in ostial lesions, probably contributing to a reduction in the restenosis rate as compared with conventional angioplasty.

Multicenter Study of Palmaz-Schatz Stents in the Renal Arteries C.R. Rees, MD*, Dallas, TX D.B. Snead, PhD* R.L. Niblett, B S PURPOSE: To report results of stents in renal arteries. MATERIALS AND METHODS: Stents were placed in 263 patients for the clinical indications of severe hypertension or renal failure and the technical indications of poor result of conventional PTA, restenosis after PTA, dissection, and lesions at risk for poor PTA results (ostial atheroma). The mean age was 66 years + 10.1; 98% of lesions were atherosclerotic, and 80% were ostial. Forty-seven percent of patients had renal insufficiency (serum creatinine level > 1.5 mg/dL). Follow-up included blood pressure measurements, laboratory analysis, and angiography (6 months). RESULTS: The technical success rate was 95%, with poststent stenosis of 4.2% ? 8.6%. Cumulative cure or improvement in hypertension by KaplanMeier analysis was 91% a t 1 month, 84% at 3 months, 70% at 6 months, and 61% a t 12 months. In patients with renal insufficiency, there was improvement in 34%, stability in 39%, and deteriorations in 27% at longest follow-up (mean, 7.9 months). Angiographic restenosis (diameter < 50%) in 150 patients occurred in 32.7%. Restenosis was lower for male patients (23%, P < .05), and for

stents dilated to a t least 6 mm (26%, P < .05), and lowest for those in both groups (10.5%, P < .05). CONCLUSION: Renal stents are useful in lesions that yield poorly to PTA, with excellent technical success. Restenosis appears to be affected by sex and size of stent or artery.

Thursday, March 30 Room 316 Scientific Session 27 TIPS MODERATOR: Janette

D. Durham, MD, Denver, CO

TIPS: Early and Midterm Efficacy in 100 Patients Z.J. Haskal, MD, Philadelphia, PA C. Cope, MD R.D. Shlansky-Goldberg, MD M.C. Soulen, MD R.A. Baum, MD M.J. Pentecost, MD PURPOSE: To assess the clinical efficacy and complications of TIPS a t a university referral hospital. MATERIALS AND METHODS: Prospective data were collected for 100 consecutive patients. The indications were variceal hemorrhage ( n = 901, asciteslpleural effusion ( n = 6), and other conditions ( n = 4). The immediate result was assessed on the basis of imaging and symptom response. Mid- and long-term efficacy was assessed on the basis of survival, Child class, and results of liver function tests, routine shunt venography, and MR angiography. RESULTS: Shunt placement succeeded in 100 consecutive cases (100%). The portosystemic gradient fell from a mean of 24 mm Hg k 3.4 to 11 mm Hg + 4.2. Bleeding stopped in 94% of acute cases, and ascites improved in 72%. The 30-day mortality was 30% (preexisting multiorgan failure in 93% cases). The late mortality was 6.9% (mean follow-up, 10 months; range, 1-34 months). The 1-and 2-year rates of primary shunt patency were 50% and 32%, and the 1-year assisted-patency rate was 89% (life table analysis). Encephalopathy was present in 23% a t 1 month (controlled in 18%) and 11% at 6 months. Liver function tests a t 3, 6, and 12 months indicate no degradation. The Child class improved one to two classes in 65%. CONCLUSION: TIPS safely and effectively treat sequelae of portal hypertension without significant midterm complication. Encephalopathy is well controlled in most cases, and furthermore diminishes over time.

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Successful Reversal of Hepatic Encephalopathy by Intentional Occlusion of TIPS R.K. Kerlan, Jr, MD, San Francisco, CA J.M. LaBerge, MD * E.L. Baker, MD * R.L. Gordon, MD * E.J. Ring, MD PURPOSE: To establish a safe and effective method for occluding a TIPS in patients who develop uncontrollable, disabling encephalopathy following the creation of the shunt. MATERIALS AND METHODS: Five patients who underwent TIPS placement developed disabling encephalopathy following the procedure. The indication for TIPS was bleeding in four patients and ascites in one. Wallstents 10 mm in diameter and 68 mm long were used to bridge the hepatic parenchyma in all patients. The onset of encephalopathy from the time of the TIPS procedure ranged from 24 hours to 3 weeks. The encephalopathy was not responsive to conventional medical management. It was therefore elected to induce shunt thrombosis by temporary inflation of an 11.5-mm-diameter latex occlusion balloon, within the midportion of the Wallstent. RESULTS: All shunts were successfully thrombosed when the balloon was inflated for a period of 12 hours or more. Encephalopathy resolved in four patients and improved in the remaining patient. Serum ammonia levels dropped significantly in all patients sampled. One patient experienced recurrent bleeding within 24 hours of the TIPS occlusion. This bleeding was controlled medically. CONCLUSION: Temporary occlusion of TIPS with latex balloons successfully induces shunt thrombosis and improves encephalopathy.

Comparative Histologic Analysis of Human and Animal TIPS J. Mendel-Hartuig, PhD, Portland, OR R.R. Saxon, MD K. Nishimine, MD V.J. Leonardo, MD J. Rabkin, MD J. Rosch, MD PURPOSE: To validate a porcine model of TIPS stenosis through a comparative histologic analysis of human and animal TIPS. MATERIALS AND METHODS: A comparison of TIPS tracts created with the Wallstent endoprosthesis from 15 explanted human shunts and 13 porcine shunts was performed, including gross pathologic examination as well as histologic characterization. Human shunts were explanted 1-18 months after TIPS placement and animals were killed 2-12 weeks after shunt placement.

RESULTS: Severe stenosis (>75% diameter narrowing) or occlusion occurred in 10 of 13 porcine shunts and in two of 15 explanted human TIPS. In both human and porcine shunts, TIPS-induced pseudointimal proliferation consisted primarily of granulation tissue (myofibroblasts and collagen) and showed no significant qualitative differences. Bile leakage was seen in six porcine and two human stenotic or occluded shunts and was associated with pseudointimal hyperplasia or thrombus in the parenchymal tract. CONCLUSION: TIPS creation using the Wallstent endoprosthesis in swine is associated with a significant early incidence of biliary leakage, pseudointima1 hyperplasia, and thrombosis. Gross morphologic and histologic changes induced by TIPS in swine accurately represent those seen in human patients. TIPS creation with the Wallstent endoprosthesis in swine therefore may be used as a model to investigate prevention and treatment of shunt malfunction. 160 4:45 PM Renal and Systemic Hemodynamics after TIPS Procedures in Patients with Intractable Ascites K. W. Sniderman, MD, Toronto, Ont F. Wong, MD L.M. Blendis, MD P.C. Liu, MD M. Sherman, MD PURPOSE: To study the effects of TIPS on systemic and renal hemodynamics and sodium homeostasis in patients with refractory ascites. MATERIALS AND METHODS: Six patients with cirrhosis and refractory ascites were studied prospectively, undergoing renal hemodynamic/sodium handling studies, complete blood volume measurement, and neurohumoral blood sampling before and after TIPS placement. At angiography, cardiac output was measured before and after TIPS. TIPS was performed with Wallstents, the end point being a CSP of 8/mm/Hg or less. RESULTS: TIPS was successful in all patients with CSP falling from a mean of 18.2 mm Hg to 7.7 mm Hg ( P < .001), and with partial ( n = 1)or total ( n = 4) relief of ascites a t 1-12 months. Cardiac output increased and systemic vascular resistance fell. Renal hemodynamics and urinary volume remained unchanged, but sodium excretion increased significantly (P = .04). At 1 month, PRA and aldosterone levels (markedly elevated before TIPS) decreased significantly; plasma norepinephrine levels (elevated before TIPS) increased markedly, then returned to baseline by 1 month. Total complete blood, pulmonary, cardiac, and central vascular volumes increased gradually after TIPS.

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CONCLUSION: Portal hypertension is important in the pathogenesis of sodium retention and ascites in cirrhosis; the increased sodium excretion after TIPS placement is due to an interplay of systemic hemodynamics and neurohumoral factors and leads to relief of ascites.

Course of Thrombocytopenia of Chronic Liver Disease after TIPS Placement J.D. Durham, MD P.C. Hugo, MD, Denver, CO S.P. Lawrence, MD D.C. Lezotte, PhD G.T. Everson, MD * B. Balir, MD PURPOSE: Thrombocytopenia of chronic liver disease remains a difficult management issue. We performed a retrospective analysis of platelet response to TIPS in 21 patients. MATERIALS AND METHODS: Platelet counts were collected 1 month prior to TIPS placement, weekly for 1month after the procedure, and monthly thereafter for 6 months. The Laird and Ware model was used to analyze platelet trends. Subgroup analyses were used to compare data for patients with pre-TIPS platelet counts of less than 100,000 ( n = 14) versus over 100,000 ( n = 71, as well as those with postshunt portal pressure gradients of less than 12 mm Hg ( n = 10) versus greater than 12 mm Hg ( n = 11). RESULTS: Analysis of the entire group demonstrated no significant change in platelet counts after TIPS. Subgroup analysis of postshunt portal pressure gradients, however, demonstrated significant increases in platelet counts when portal right atrial pressure gradients were reduced to 12 mm Hg or less. CONCLUSION: This study suggests that thrombocytopenia associated with chronic liver disease may be improved by TIPS when postshunt portal pressure gradients are reduced to less than 12 mm Hg.

TIPS with Polytetrafluoroethylene-covered Stents: Experimental Results in Swine R.R. Saxon, MD, Portland, OR K. Nishimine, MD H. Shim, MD, PhD H.A. Timmermans, BFA* F.S. Keller, MD J. Rosch, MD, et a1 PURPOSE: To evaluate the ability of polytetrafluoroethylene (PTFE)-covered stents to improve TIPS patency. MATERIALS AND METHODS: Covered TIPS were created in 13 swine by using 40-45-mm-long PTFE anchored by Z stents and centrally supported by Wallstents. Thirteen other swine had uncovered

TIPS using Wallstents alone. Animals were followed up with portal venography until the shunt occluded or became severely stenotic (> 75% diameter narrowing) and were then killed. Gross pathologic and histologic evaluations were performed. RESULTS: In the uncovered group, nine shunts occluded and one was severely stenotic 4 weeks after TIPS placement (77%);only three shunts were patent (23%). Bile leakage was discovered in six occluded shunts on gross pathologic inspection. Hepatic vein stenosis occurred in one shunt. In the covered group, nine of 13 shunts (69%) remained patent for at least 4 weeks and up to 3 months after TIPS placement. Three shunts occluded and one was severely stenotic by 4 weeks (31%). Bile leakage was discovered in two compromised shunts at pathologic evaluation. Intimal hyperplasia in the hepatic vein above the PTFE covering led to three severe stenoses and tended to be responsible for late shunt malfunction. CONCLUSION: PTFE covering significantly improved TIPS patency. However, stenosis in the hepatic vein at the top of the graft material led to late shunt malfunction in selected cases.

Thursday, March 30 Room 305 Scientific Session 28 Thrombectomy and Arterial Thrombolysis MODERATOR:

Karim Valji, MD, San Diego, CA

Intrathrombotic Repeated Wedge Infusion of High-Dose Urokinase in Chronic Atherosclerotic Occlusions M. Sato, MD, PhD, Wakayama, Japan R. Yamada, MD K. Kishi, MD T. Sonomura, MD M. Kimura, MD H. Tanihata, MD, et a1 PURPOSE: To evaluate the effects of intrathrombotic repeated wedge infusion of high-dose urokinase in chronic arterial occlusions in which the guide wire does not pass through initially. MATERIALS AND METHODS: Thirty-two occlusions (four aortoiliac, 17 common and external iliac, seven femoral, four popliteal below knee) in 28 cases were studied. The length of the occlusions ranged from 3 to 35 cm (average, 14.1 cm ? 7.5). The ages of occlusions were identified with angiog-

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raphy, AAI, and ischemic symptoms. The duration of occlusion ranged from 3 to 6 months in 18 occlusions and was more than 6 months in 14 occlusions. The guide wire (0.032-inch soft tip) did not go through the occlusive segment in each case initially. A 3- or 4-F catheter was inserted and advanced just before the occlusive site where the guide wire did not pass through. High-dose urokinase (10,000 IU per 10 mL of saline per minute) was directly injected into the thrombus in wedge state until the blood came out through the catheter. The method was continued to achieve complete recanalization. After recanalization, additional PTA was performed in each case. RESULTS: The total volume of urokinase was 360,000-1,200,000 IU in 360-1,200 mL of saline (average volume, 722,000 IU in 722 mL of saline). The injection time was 36-120 minutes. The initial complete recanalization rate was 80%; the 2-week patency rate, 75%; and the 1-year patency rate, 68%. CONCLUSION: Our results show that chronic arterial occlusions can be recanalized within 2 hours with intrathrombotic high-dose urokinase infusion.

Long-term Experience with Pulse-Spray Thrombolysis of Occluded Peripheral Arteries K. Valji, MD, San Diego, CA A.C. Roberts, MD S.B. Ogleuie, MD J.J. Bookstein, MD* PURPOSE: To evaluate the efficacy and safety of pulse spray pharmacomechanical thrombolysis (PSPMT) in the treatment of occluded peripheral arteries. MATERIALS AND METHODS: Fifty-two arterial occlusions (one aortic, 15 iliac, 23 femoral, 12 popliteal, one tibial) were treated with PSPMT using urokinase. Highly concentrated fibrinolytic agent admixed with heparin was injected as a high-pressure spray directly into the thrombus with use of a multiside slit catheter. RESULTS: The mean urokinase dose was 515,000 IU + 227,000. The mean time for lysis was 98 minutes ? 55. Balloon angioplasty was performed after all readily lysable clot was dissolved. Successful recanalization with improved blood flow to the extremity was achieved in 94% of cases. One patient developed a groin hematoma requiring surgical evacuation. Distal ernbolization occurred in five patients; two cases were successfully treated with local thrombolytic therapy, one required no therapy, and two required operative treatment.

CONCLUSION: PSPMT is an effective, reliable, and safe method to achieve rapid lysis of peripheral arterial occlusions. Thrombolytic Therapy Compared with Mechanical Recanalization in Chronic Peripheral Arterial Occlusions: A Randomized Pilot Trial M.F. Meyerouitz, MD, Boston, MA D. Didier, MD J. Vogel, MD L. Soulier-Parmeggiani, MD H. Bounameaux, MD PURPOSE: To evaluate whether thrombolysis followed by angioplasty is superior to angioplasty alone for the treatment of chronic peripheral arterial occlusions. MATERIALS AND METHODS: Twenty patients with claudication or limb-threatening ischemia and symptoms of at least 3 weeks were randomized either to thrombolytic therapy with rt-PA for up to 4 hours followed by angioplasty or to angioplasty alone. Clinical follow-up was obtained for 1 year. RESULTS: Life-table analysis revealed significant improvement in the patency rate for claudicants treated initially with thrombolysis followed by angioplasty compared with angioplasty alone (P = .02). The four patients with limb-threatening ischemia were all randomized to thrombolytic therapy and none exhibited continued patency at 1 year. The most common complication in the thrombolysis group was peripheral embolization; three of these four patients were among those who had limbthreatening ischemia as the indication. There was no increased incidence of bleeding with thrombolytic therapy. CONCLUSION: A short course of thrombolytic therapy prior to angioplasty appears to improve the 1year patency rate for claudication due to iliac or femoropopliteal occlusions. Patients with limbthreatening ischemia have a high incidence of peripheral embolization and dismal patency rates with this form of therapy. Percutaneous Mechanical Thrombectomy with Use of the Hydrolyser System H.P. Rousseau, MD, Toulouse, France M.R. Sapoual, MD L. Gieskes F. Joffre J.C. Gaux, MD PURPOSE: A new mechanical thrombectomy system (Hydrolyser) using the Venturi effect was applied for thrombus removal. We present our clinical experience with this device in arterial grafts, native arteries, and hemodialysis shunts. MATERIALS AND METHODS: The Hydrolyser is a recently developed 7-F double-lumen hydrodynamic

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thrombectomy catheter. The device has been used in 16 patients (three female, 13 male) with recent thromboses (4.8 days 31, in arterial grafts ( n = 41, native arteries ( n = 7), hemodialysis shunts ( n = 5), and TIPS ( n = 1). RESULTS: Declotting was achieved in less than 15 minutes, with the underlying stenoses corrected with PTA ( n = 7) or stent placement ( n = 5). Complete success was achieved by the Hydrolyser alone in 11cases, with fibrinolysis in four cases, and with surgery in one case. Complications were noticed in four patients but were all resolved percutaneously (two distal migrations treated with thromboaspiration and two local dissections treated with Wallstent implantation). CONCLUSION: The Hydrolyser system seems promising for percutaneous thrombectomy, is not associated with significant complications, and appears faster than fibrinolytic agents. It may be an effective alternative to thrombolysis.

*

167 5:OO PM Comparison of Vessel Wall Reaction after Treatment with the Hydrolyser (Hydrodynamic Thrombectomy Catheter) and the Fogarty Thrombectomy Catheter V.G. van Ommen, MD, Maastricht, Netherlands E.H. van der Veen, PhD J. Habets M. Daemen, PhD G. Geskes, MD W. Dassen, PhD, et a1 PURPOSE: In most thrombectomy devices, direct contact with the vessel wall is unavoidable, leading to intimal hypertrophy and restenosis. We compared the intimal reaction of a new device, the Hydrolyser, with the Fogarty thrombectomy catheter. MATERIALS AND METHODS: The Hydrolyser is a 7-F double-lumen catheter developed for the percutaneous removal of intravascular thrombus. The mode of operation is by the Venturi effect created by a high-velocity saline jet directed over a side hole near the tip of the catheter. Thrombus is sucked into the side hole, destroyed by the jet, and removed through the wide discharge channel. The intimal reaction of peripheral arteries was evaluated in seven goats 3 weeks after the passage of a Hydrolyser or Fogarty thrombectomy catheter. The diameter of all vessels was determined with intravascular US prior to the procedure. Only vessels larger than 3 mm were included. RESULTS: Of 29 segments treated with the Hydrolyser, 24 showed no intimal hypertrophy, four had one to five layers, and one had more than five layers. In 26 segments treated with the Fogarty thrombectomy catheter, these categories included eight, five, and 13 segments, respectively; in 19 control

segments (only intravascular US), 14, five, and zero segments, respectively ( P < .0001). CONCLUSION: The vessel wall reaction after use of the Hydrolyser was minimal and significantly less than after use of the Fogarty thrombectomy catheter.

Steps Toward Percutaneous Transcatheter Embolectomy with the Modified Fogarty Maneuver: In Vitro Results J. Brossman, MD, Kiel, Germany T. Jahnke A. Beress J. Link, MD M. Heller, MD PURPOSE: Development of a new interventional procedure and catheter to perform percutaneous embolectomy in a modified Fogarty maneuver. MATERIALS AND METHODS: A funnel-shaped catheter tip was developed and attached to 7-9-F introductory sheaths. In vitro, embolectomies were performed with 3- and 4-F Fogarty embolectomy catheters, using 10-12-day-old coagulated swine blood. To define the best ratio of embolectomy catheter and introductory sheath, embolectomies were performed in a 7-mm-diameter silicone tube. In a flow model simulating popliteal and tibia1 vessels, embolectomies were performed with unblocked and blocked flow. The percentage of extracted thrombus and amount of thrombus per Forgarty maneuver were calculated. RESULTS: The amount of extracted thrombus was significantly correlated with the ratio of catheter shaft size and French size of the introductory sheath. The best combination found was a 9-F introductory sheath and 3- and 4-F embolectomy catheters in the nonflow model, averaging a 90%-95% extraction rate. In the blocked flow model, embolectomy rate was significantly better than in the non blocked model, also averaging 90%. CONCLUSION: The initial results indicate that controlled percutaneous embolectomy in a modified Fogarty technique is feasible. Developments concerning the final design and introduction of the catheter and thinner and steerable Fogarty catheters are necessary.

1995 SCVIR Meeting Abstracts

65

Volume 6 Number 1

Thursday, March 30 Room 304 Scientific Session 29 Gastrointestinal and Tracheobronchial Stents MODERATOR:

Frederick S. Keller, MD, Portland, OR

Expandable Metallic Prosthesis in Treatment of Low Intestinal Occlusion M.A. Herrera, MD, Zaragoza, Spain A.T. Mainar, PhD M.A. De Gregorio, PhD R.C. Tobio, PhD E.A. Alfonso, PhD Tejero PURPOSE: To determine the efficacy of expandable metallic prostheses in the management of acute low intestinal occlusion of neoplastic etiology and for avoiding the creation of a temporary colostomy. MATERIALS AND METHODS: Ten patients (six male and four female) with acute low intestinal occlusion demonstrated by barium enema underwent placement of 10 expandable metallic prostheses in colonic and rectal stenoses. First, we canalized the stenotic area with a glide wire (0.035 inch) under radiologic guidance. Second, the prosthesis carrier system was passed through and the prosthesis was located inside the stenotic area, allowing normal air and stool discharge. Histologic examination and tumor staging was performed as well as definite operation 6-7 days after implantation of the prosthesis (resection and end-to-end anastomosis). RESULTS: Acute intestinal occlusion was resolved in all cases with stool discharge immediately after implantation. Resolution of abdominal distention was incomplete in one case. CONCLUSION: Implantation of expandable metallic prostheses is, in our experience, a feasible solution for solving intestinal occlusion permitting one-step surgery and avoiding the creation of a temporary colostomy. 4 : 1 5 ~ ~ 170 Self-expandableMetallic Endoprostheses in Malignant Esophageal Obstruction A.F. Watkinson, FRCR, London, England J. Ellul, FRCS R. Khan, MBBS R.C. Mason, FRCS A.N. Adam, MD PURPOSE: To assess the role of self-expandable metallic endoprostheses in malignant esophageal obstruction. MATERIALS AND METHODS: Thirty patients (20 men, 10 women; mean age, 64 years; range, 52-88

years) with malignant esophageal obstruction underwent insertion of self-expanding metallic endoprostheses. In 15 patients the polyurethane-covered Wallstent was inserted; in 10 patients, the nitinol Strecker stent was inserted; and in five patients the polyethylene-covered Gianturco stent was inserted. All patients had severe swallowing difficulties a t presentation with a dysphagia score of 3 or 4 (0 = normal diet; 1 = some solid food; 2 = semisolid food; 3 = liquids only; 4 = complete dysphagia). All patients were followed up and assessed a t 4 weekly intervals until death. RESULTS: All patients had successful stent insertion and could subsequently eat a relatively normal diet (dysphagia score 0 or 1). The mean hospital stay following stent insertion was 4.4 days (range, 2-17 days) with a mean follow-up of 4.7 months (range, 17-207 days). Complete stent migration occurred in three patients (10%) (one Wallstent; two Gianturco). There were no other significant complications. CONCLUSION: The technique of self-expanding metallic esophageal stent insertion is a safe and effective treatment for malignant esophageal dysphagia, which can rapidly alleviate symptoms and permit near normal swallowing. 171 4 3 0 PM Life-threatening Esophageal Fistula: Treatment with Expandable Metallic Stents Covered with Biosynthetic Skin T. Sakai, MD, Fukui, Japan N. Hayashi, MD, PhD T. Kimoto, MD Y. Ishii, MD PURPOSE: Fistula formation is the most serious complication often found in thoracic malignancies. We evaluated the effectiveness of the metallic stents covered with biosynthetic skin to close the fistula and facilitate oral intake. MATERIALS AND METHODS: Four patients with an esophageal fistula were treated by means of metallic stents covered with biosynthetic skin. Three fistulas were located in the bronchial tree, and the other one was located in the mediastinum. All of them were complicated by pneumonia or a mediastinal abscess. All the stents were handmade into the Rosch-modified Z or spiral Z stent. The proximal and distal portions of the stents were formed 5-10 mm wider than the body to prevent stent migration. Biosynthetic skin was sewn on expandable metallic stents with a nylon monofilament to cover the complete surface of each stent. RESULTS: Stent insertion was successfully performed in all cases. Migration after the procedure did not occur. In all cases, the fistulas were com-

66

Journal of Vascular and Interventional Radiology

January-February 1995

pletely sealed and pneumonia and the mediastinal abscess improved. Oral intake was possible for 2-20 weeks without symptoms in all the cases. Major complications did not occur. CONCLUSION: An expandable metallic stent covered with biosynthetic skin is a safe and effective tool for the treatment of an esophageal fistula.

Covered Wallstent Endoprostheses in Treatment of Esophageal Perforation A.F. Watkinson, FRCR, London, England J. Ellul, FRCS K. Enwisle, FRCR M. Farrugia, MRCP R.C. Mason, FRCS A.N. Adam, MD PURPOSE: To compare conservative methods with insertion of plastic-covered Wallstent endoprostheses in the management of esophageal perforation in advanced malignancy. MATERIALS AND METHODS: Twenty-nine patients suffered perforation following esophageal dilatation prior to endoscopic laser therapy. Twentythree patients were treated nonoperatively with intravenous antibiotics, intravenous feeding, and H2 receptor blockade. Six patients were treated with covered Wallstent endoprostheses. After administration of intravenous sedation, stents 20 or 25 mm in diameter were inserted with the plastic-covered section across the perforated segment. RESULTS: There were three deaths (13%)among the patients treated conservatively; the remainder recovered after extended hospital treatment. In all six patients treated radiologically, stent placement was successful with excellent results: all patients had immediate relief of dysphagia. Follow-up upper GI studies a t 24 hours showed no contrast medium extravasation. All patients left hospital within 3-4 days on a normal diet without suffering any of the serious sequelae frequently associated with esophageal perforation. CONCLUSION: The technique of covered esophageal stent placement is rapid, safe, and effective and is now our treatment of choice for this difficult problem following esophageal dilatation prior to laser therapy.

Results and Complications of Endobronchial Stent Placement for Benign Disease W.R. Austin, MD, Minneapolis, MN D. W. Hunter, MD H. Bjarnason, MD M.I. Hertz, MD B.C. Cahill, MD PURPOSE: The study was undertaken to retrospectively review the results and complications of all

cases of bronchial stent placement a t our institution. MATERIALS AND METHODS: Nine patients received endobronchial stents between 1989 and 1994. Eight of nine patients had lung transplants. Complications during and after stent placement were tabulated as well as changes in technique that evolved with experience. RESULTS: All patients are still alive and clinically improved. All patients in respiratory distress had immediate clinical im~rovement.Five Gianturco stents were placed across upper lobe bronchus origins without problems. A Gianturco Z stent eroded through the bronchus and was treated with surgical banding and placement of a Palmaz stent. Massive hemoptysis developed from granulation tissue inside the Palmaz stent, which was treated with laser cautery and bronchial artery embolization. There were two cases of collapsed Palmaz stents, treated with placement of a Gianturco Z stent inside the reexpanded Palmaz stent. Three Gianturco stents slipped after placement and were removed and replaced. Seven of nine patients required more than one procedure to attain or maintain the desired clinical result. CONCLUSION: Endobronchial stent placement has evolved into a successful method of treating bronchial stenosis. The large open spaces of the Gianturco stent make it particularly attractive for bronchial stent placement.

174 5:15~~ Self-expandingMetallic Stents for Nonoperable Tracheobronchial Stenoses and Malacia D.S. Ball, DO, Philadelphia, PA G.S. Cohen, MD G.M. O'Brien, MD G.J. Criner, MD J.M. Travaline, MD S. Furakawa, MD, et a1 PURPOSE: To evaluate the utility of self-expanding metallic stents in the management of nonoperable tracheobronchial stenoses and malacia. MATERIALS AND METHODS: Pre-implantation plain radiographs, CT scans, and bronchoscopic and pulmonary function studies were obtained. Radiographic, bronchoscopic, and physiologic evaluation were correlated to assess need for stent placement and stent sizing. Fluoroscopy and bronchoscopy were used to place self-expanding metallic stents (11Wallstents, one Gianturco stent) in seven patients. Five patients had lung transplants, one had a postintubation stricture, and one had contralatera1 bronchial narrowing secondary to pneumonectomy. RESULTS: Self-expanding metallic stents were successful in relieving symptomatic stenoses and mala-

1995 SCVIR Meeting Abstracts 67 Volume 6 Number 1

cia in all seven patients. One patient required bronchoscopic removal of two Wallstents and placement of a Gianturco Z stent to allow unimpeded aeration at a bronchial bifurcation. Significant improvement in pulmonary function tests resulted from stent placement in all patients. CONCLUSION: Self-expanding metallic stents are useful in the management of nonoperable tracheobronchial malacia and stenoses. Choice of proper stent configuration is essential for success. Continued follow-up with bronchoscopy and pulmonary function studies is being conducted.