Poster Session 2

MATERIALS AND METHODS: The first portion of the

graft to be deployed consisted of two anchoring Z stents connected by struts over which a small-pore polyester tube was placed and attached. A triple-body inner Z stent was then placed within the graft lumen between the anchoring stents. A coaxial delivery system was designed for the two-stage deployment, which was evaluated in eight dogs. RESULTS: Graft delivery was completely successful in

four cases. In the second and third dogs, the lumen of the graft material had to be recatheterized for deployment of the inner stent because of technical problems with the delivery system. These problems were solved by improving the method for joining the sections of the delivery system. In two animals, premature deployment of the inner stent resulted in a wide gap between this stent and the caudal anchoring stent. The gap was easily bridged with a single body Z-stent in both animals. CONCLUSION: Endovascular assembly of an aortic stent

graft is feasible. This approach to graft deployment reduces the size of the delivery system, which may obviate the need for a cutdown. Take Home Points: Endovascular assembly of an aortic stent graft is feasible and reduces the size of the required delivery system.

Monday, March 10, 1997 3:30-5:00 pm Poster Session 2

cally significantly higher (P < .05) in those patients with high systolic blood pressure (;;" 160 mm Hg), anticoagulant therapy during UGCR procedure, and wide pseudoaneurysmal neck (;;" 2 mm), in comparison with the control patients. CONCLUSION: Hypertension and anticoagulant usage as well as the wide neck of pseudoaneurysm are three significant factors that contribute to failure of UGCR of postcatheterization femoral artery pseudoaneurysms.

Take Home Points: Hypertension should be managed for a successful UGCR procedure. 3:40 pm Changes in the Aortic Bifurcation Angle in the Presence of Abdominal Aortic Aneurysms T. Fathy Massoud, MD, Los Angeles, CA • G j. Hademenos, PhD • j. W Sayre, PhD •

E. W.l. Fletcher, MD PURPOSE: To compare values of the aortic bifurcation

angle (ABA) in the presence of abdominal aortic aneurysms (AAAs) with those from normal subjects. MATERIALS AND METHODS: The ABA was measured on frontal angiograms of 71 patients (37 males and 34 females; mean age, 66 years) with nondiseased aortas and common iliac arteries, and 27 patients (17 males and 10 females; mean age, 69 years) with angiographically documented AAAs. Statistical analysis was performed

with multivariable (age, sex, and AAA presence) linear regression analysis and a two sample KolomogorovSmirnov test for equality of distributions.

3:30 pm Factors Contributing to Unsuccessful US-guided COD1pression Repair of PostcatheteriZation pseudoaneurysms X. Yang, MD, PhD, Kuopio, Finland • H. Manninen, MD, PhD· E. Kaukanen, MD • S. SOimakallio, MD, PhD PURPOSE: To clarify the factors contributing to failure of

US-guided congression repair (UGCR) of postcatheterization femoral arterial pseudoaneurysms. MATERIALS AND METHODS: We reviewed the clinical courses of 5,632 patients who underwent different car-

diovascular catheterizations through a femoral approach during the period of 2 years. Femoral arterial pseudoaneurysm was found in 45 (0.8%) patients. Altogether, 17 factors including patient's clinical features, anticoagulant therapy, catheterization procedures, UGCR procedures, and pseudoaneurysmal characteristics, were analyzed by using the statistics of multiple logistic regression. RESULTS: The pseudoaneurysms were successfully treated with UGCR in 37 (82.2%) patients. Another eight (17.8%) patients with unsuccessful UGCR required sur-

252

gical repair. The frequency of UGCR failure was statisti-

RESULTS: The range of ABAs for normal subjects was 15°-80° (mean, 39.0°) and that in the presence of AAAs was 15°-120° (mean, 57.4°). The Kolomogorov-Smirnov test yielded a statistical result D = 0.4674, which was highly significant (P < .00001). A strong bimodal distribution (with a peak at acute angles [mode 20°] and another peak at obtuse angles [mode 90°]) was observed

for values of ABAs in the presence of AAAs. The ABAs of normal subjects showed a unimodal distribution (mode 40°). There was no statistical correlation between ABA and patient age or sex. CONCLUSIONS: When compared to normal, the ABA changes significantly in the presence of an AAA to assume either a markedly acute configuration or an obtuse splaying. Knowledge of these induced alterations in ABA is useful in understanding the morphogenesis of AAAs and as reference values for endovascular procedures centered on the aorto-iliac junction, including stent graft placement.

Take Home Points: 1. AAAs induce changes in the aortic bifurcation angle (ABA), which becomes either very acute (- 20°) or obtuse (- 90°) compared to normal (- 40°).

2. ABA reference values are presented for procedures centered on the aorto-iliac junction.

3:50 pm

Percutaneous Treatment of Iliac Aneurysms Using a Covered Stent: First Long-term Results E. Minar, MD, Vienna, Austria • A. Ahmadi, MD • H. Ehringer, MD PURPOSE: Infrarenal abdominal aortic aneurysms are often extending into the iliac arteries. Otherwise, isolated

aneurysms of the iliac arteries are rare, and such aneurysms are mostly located in the common iliac artery. The potential complications (rupture, thrombus formation with peripheral embolization) require the exclusion of such aneurysms. The development of covered stents offered the possibility for percutaneous transluminal treatment of such aneurysms. We report our initial clinical experience and first long-term results with this treatment. PA7JENTS AND METHODS: We treated five consecutive

male patients (mean age, 71; range, 66-78 years) with an isolated atherosclerotic iliac aneurysm (4 x common iliac artery, 1 x common and external iliac) by percutaneous transluminal implantation of a self-expanding nitinol stent covered with polyester fabric (Cragg Endopro). The diameter of the aneurysms was between 20-30 mm. The stents had a diameter of 10-12 mm and a length of 6-8 cm. The implantation was done in local anesthesia with use of a 8 (9) F sheath. RESULTS: The implantation was successful in all five pa-

tients with immediate exclusion of the aneurysm. There were no complications. Follow-up investigations (colour duplex sonography; spiral-CT; intravenous DSA) at 6-15 months demonstrated optimal results (correct stentposition, patency, no leaks, complete thrombosis of the aneurysm) in all patients. CONCLUSION The isolated iliac aneurysm is an optimal

indication for implantation of a covered stent. This treatment should be considered as the primary therapy of choice in such patients.

Take Home Points: Iliac aneurysms can be easily treated by percutaneous implantation of a covered stent. Our first long-term results indicate definite exclusion of the aneurysm. Therefore, this treatment modality should be considered as the primary therapy of choice. 4:00 pm

Percutaneous Pulmonary Thrombectomy E. V Lang, MD, Iowa City, L4 • WH. Barnhart, RTR • DL Walton, RTR PURPOSE: To present a system for efficient percutaneous

pulmonary thrombectomy that uses readily available components.

MATERIALS AND METHODS: A thrombectomy system was developed in the laboratory and was refined during use in three patients with massive severely symptomatic pulmonary thromboembolism underwent. Components include a 14-F stationary sheath, a 14-F ultrathane suction catheter, and a coaxially loaded 6-F guiding catheter.

RESULTS: Thrombolysis and mechanical clot maceration

failed in the two patients in whom it was tried. A three to 8-cm-long elastic clot with histologic signs of maturation was aspirated, reducing the clot burden more than 90% in each case. Best results were obtained when the 14-F suction catheter was advanced coaxially over the guiding catheter compacting, trapping, and propelling the clot distally until it halted at a vascular bifurcation. Amputation of the clot during retrieval was minimized by the use of a tear-away sheath that was inserted into the stationary sheath. Hemodynamics improved significantly and immediately after clot suction. Two patients recovered during their hospital stay; the third died of right heart failure the following day. CONCLUSION Percutaneous thrombectomy can be an attractive alternative to open surgery for patients who fail medical management of massive pulmonary thromboembolism.

Take Home Points: 1. Mature pulmonary emboli may resist thrombolysis and mechanical maceration, but can be suctioned easily 2. Percutaneous pulmonary thrombectomy is fast and safe 3. Readily available components can be used for pulmonary thrombectomy 4:10 pm A Ne-w Expanded-Tip Vascular Catheter for

Percutaneous Thrombectomy-Preliminary In Vivo Results j. Brossmann, MD, Kiel, Germany • K. Arun, MD •

J j. Bookstein, MD PURPOSE: To test the safety and efficacy of an ex-

panded-tip vascular catheter (EVC) designed for percutaneous transcatheter balloon thrombectomy. MATERlALS AND METHODS: Nine French EVC prototypes (Applied Medical, Laguna Hills, CA) were percutaneously introduced into the femoral arteries of four 20 kg dogs. The funnel-shaped tips were deployed in the iliac arteries to simulate embolectomy maneuvers. Histologic alterations secondary to deployment were evaluated in two dogs acutely, and in two dogs after 3 weeks.

Supported by: Applied Medical, Laguna Hills, CA

253

Efficacy of thrombic extraction was evaluated in a rabbit subacute inferior vena cava thrombosis model, using 2 day (n = 8) and 7 day (n = 4) old thrombus. RESULTS: Histologic examination at the site of funnel and balloon deployment immediately after the procedure revealed areas of minimal endothelial disruption and subtle hemorrhage and injury. Three weeks after the intervention, subintimal myointimal hyperplasia was present at each site, and in two of four sites, hemorrhagic residua were found in the media. In the rabbit model, 2-day-old thrombus was completely removed from the inferior vena cava by two or three extraction maneuvers. With 7-day-old thrombus, embolectomy was successful in only two of four rabbits. CONCLUSION Preliminary in vivo experience suggests the feasibility of percutaneous thrombectomy using a new EVC device. Efficacy of the device may be limited by age of thrombus.

Take Home Points: New device for percutaneous thrombectomy; safe introducibility in animal model; good extraction rate in vivo. 4:20 pm Increasing Activity of rt-PA Induced Fibrinolysis at Hyperthermia: In Vitro Results and Possible Clinical Impacts

4:30 pm Thrombectomy Time and Embolization Rate of Different Hydrodynamic Thrombectomy Devices: In Vitro Results S. Mueller-Huelsbeck, MD, Kiel, Germany • H. Schwarzenberg, MD • j. Link, MD • C. Bangart, MD • M. Heller, MD

PURPOSE: To compare the hydrodynamic thrombectomy devices Hydrolyser™ (HL) and S.E.T. ™ (SED in an in-vitro model. MATERIALS AND METHODS: In a flow-model (flow 1 Umin), made of silicone tubes femoral artery with severe stenosis was simulated. Thrombectomy of clots (n = 40) from 8 days old porcine blood (7.33 ± 0.41 g) was performed with either HL or SET. The catheters were both used without, the HL also with guide wires (0.018-0.025 inch). Ten thrombuses were treated in each group. Thrombectomy time, dosages of applied and aspirated saline were measured. Emboli were counted in 10, 100, and 1000 pm porus filter.

PURPOSE: To investigate the influence of hyperthermia on activity of rt-PA induced fibrinolysis.

RESULTS: Mean thrombectomy time was similar for SET (35.3s) and HL (34.5s). It was prolonged, if HL was used with giude wires (55.1 s/72 s). Quotients of applied and aspirated saline were 0.59/0.85/1/1.23 (P < 0.01). Emboli measuring 1000 pm appeared 1/10, 4/10, 3/10, 3/10 (P < .08). More than six emboli greater than 100 pm were counted 1/10, 2/10, 6/10, 5/10 (P < .08), Significant 10 pm emboli were not observed.

MATERIAL AND METHODS: Standardized fibrin-clots were incubated for 5 hours either with rt-PA or sodium chloride and blood plasma at temperatures of 30°C to 45°C in a water bath. Concentrations of D-dimers and time until complete clot lysis were measured.

CONCLUSIONS: The HL causes slightly more embolisms than the SET, emboli rate increases with the use of guide wires. Disadvantageous of the SET is that more saline is aspirated than applied. In-vivo this leads to hemolysis and a decrease of hemoglobin.

RESULT'S: No temperature-optimum of rt-PA activity was found. Lysis time continued to decrease even at the highest temperature tested in the study. The activity of fibrinolysis with rt-PA showed an exponential rise with increasing temperature (r = 0.99) and approximately doubled from 30°C to 40°C. Concentrations of D-dimer approximately trebled between 30°C and 40°C. In the control group clot-size did not change under addition of sodium chloride.

Take Home Points: 1. The described embolectomy devices are different in embolization rate and aspirated saline, which might provide clinical complications.

CONCLUSIONS: The activity of rt-PA induced fibrinolysis distinctly increases with higher temperatures up to 45°C. Especially in patients with occlusive artery disease and decrease of body temperature of the afflicted extremity, reduced activity of fibrinolysis with rt-PA can be expected.

j. Maass, MD, Novara, Italy • P. Fonio, MD • G. Gandini, Prof· A. Scarrone, MD • C. Ferro, Prof

H. Schwarzenberg, MD, Kiel, Germany • S. Mueller-Huelsbeck, MD • j. Brossman, MD • F. Wesner, MD • M. Heller, MD

254

Take Home Points: Activity of rt-PA induced fibrinolysis is increased at hyperthermia up to 45°C. Decreased activity of rt-PA can be expected at the peripheral site.

2. Time of thrombectomy is equal.

4:40 pm Percutaneous Treatment of Procedure-related Complications of TIPS

PURPOSE: Aim of the present paper is to present our experience in the percutaneous treatment of complications during TIPS.

MATERIAL AND METHODS: During the past 4 years, in the Radiology Departments of the Novara and the Cuneo Hospital, 106 patients underwent TIPS. Eleven immediate complications occurred: six cases of stent displacement, all resolved by transferring the stents elsewhere; one occlusion, resolved by performing another anastomosis; one case of displacement of a coil into the portal trunk, which was retrieved through the introducer sheath; one pseudoaneurysm of the gastroduodenal artery, embolized angiographically; one artero-portal shunt, occluded by a distachable balloon; and one hemobilia resolved by application of a biliary drainage catheter. RESULTS: Percutaneous treatment was successful in all complications. CONCLUSION Complications during TIPS can be resolved percutaneously by skilled operators if the required material is available.

Take Home Points: Eleven immediate complications of TIPS were resolved percutaneously: six stent displacements; one occlusion; one displacement of a coil; one pseudoaneurysm; one hemobilia; and one artero-portal shunt. 4:50 pm Anchoring Coil Embolization in a High-Flow Arterial Model: A Pilot Study A. K6nya, MD, PhD, Houston, IX. KG. Wright, PhD. S. Wallace, MD* PURPOSE To devise and test an occluding coil anchoring system to improve the safety of coil embolization. MA TERlALS AND METHODS: A newly devised anchoring system was attached to Gianturco coils and investigated in 15 pigs. In an acute study, an anchored coil was placed in the infrarenal portion of the abdominal aorta in 12 pigs by means of the carotid approach. Aortography was performed before and after coil placement. In a chronic study, anchored coils of the appropriate size were placed in the left femoral and the right carotid arteries in three pigs by means of the right femoral approach. One week later, the animals were evaluated for vascular occlusion and coil migration. RESULTS: Radiographically, the coil created a compact conglomerate. In the acute group, necropsy confirmed compact arrangement of the coils within the aortic lumen and containing an anchored coil were completely obstructed and no coil migration was noted.

Wednesday, March 12, 1997 3:30-5:00 pm Poster Session 3 3:30 pm Intraarterial Infusion of Zinostatin Stimalamer for Hepatocellular Carcinoma: Predisposing Factors for Complications A. Nakatsuka, MD, Tsu, japan • K Yamakado, MD • N. Tanaka, MD • K Matsumura, MD • K Takeda, MD • T. Nakagawa, MD PURPOSE: To assess predisposing factors for complications after intra-arterial infusion of zinostatin stimalamer (SMANCS), which is a new oily anticancer drug to treat hepatocellular carcinoma (HCC). MATERIALS AND METHODS: Sixty patients with HCC received intraarterial infusions of SMANCS in 92 procedures. The injected dose ranged 1-6 mg 0-4 mg; 69 procedures, 4-6 mg; 23 procedures). Injection was done at segmental branches in nine procedures, at lobar branches in 37 procedures and at proper hepatic arteries in 46 procedures. Gelatin sponge embolization was added in 22 procedures. Patients' clinical stage classification was as follows, according to the rules established by Liver Cancer Study Group of Japan; I in 33 procedures, II in 52 procedures and III in seven procedures. Change of serum bilirubin level and evidence of ascites were evaluated before and within 3 weeks after the treatment. RESULTS: Hyperbilirubinemia (~ 3.0 mg/dO or newly developed ascites appeared 12% of stage I patients (four of 33 procedures), 29% of stage II patients OS of 52 procedures), and 86% of stage III patients (six of seven procedures). Of seven patients with stage III, three patients died of liver failure within 1 month. There were no significant relationships between the injected dose or injection site of SMANCS, or the combination use of embolization and adverse of liver profiles. CONCLUSION Occurrence of the adverse effect after SMANCS injection depends on the basis of clinical stage class degree.

Take Home Points: Adverse of liver function after SMANCS injection is closely related to the clinical stage class. 3:40 pm

CONCLUSION The newly devised anchoring system effectively prevented migration of vascular occluding coils even in high flow conditions.

Management of Guide Wires Entrapped By Vena Cava Filters during Central Venous Catheter Placement R. T. Andrews, MD, Baltimore, MD • j.F. Gerschwind, MD • Sf. Savader, MD • FA. Osterman, jr, MD

Take Home Points: An anchoring system makes vascular embolization with coils safer by preventing coil migration. This in tum could extend the scope of coil embolization.

INTRODUCTION Vena cava filters have been used as prophylaxis against pulmonary embolism since 1967 and it is estimated that 20,000-30,000 filters are placed annually in the United States. The presence of a vena cava

255