Scientific Session 19 Risk Reduction in Diagnostic Angiography

9 cases, 2 deaths (22%) occurred in patients with extensive hepatic replacement by tumor where embolotherapy was used in an attempt to arrest tumor growth. CONCLUSION: Hepatic embolotherapy in patients with neuroendocrine tumors metastatic to the liver may be used for control of pain, as well as hormonal symptoms. This therapy should be used cautiously, if at all, in an attempt to control progression of disease in the otherwise asymptomatic patient.

3:45 pm Hepatic Arterial Chemoembolization With Streptozotocin in Patients With Liver Metastases of Endocrine Digestive Tumors Alban Denys, MD, Qichy, France. Sophie Dominquez, MD. Annie Sibert, MD. Philippe Ruzniewski, MD. Valerie Vilgrain, MD. Yves Menu, MD PURPOSE: To evaluate the efficacy of chemoembolization of liver metastases from digestive endocrine tumors using Streptozotocin (STZ). This drug is known as the most efficient systemic chemotherapy of this disease. MATERIAL AND METHODS: 15 patients with progressive liver metastases from carcinoid tumors (n = 8) or islet cell carcinomas (ICC, n = 7) were prospectively included in this study. STZ was administered under general anesthesia in emulsion wit Lipiodol and associated to embolization with Gelfoam particles. This treatment was repeated in 12 cases 2 to 6 times (median 3) (one session in 3 cases). Median follow-up was 16 months (1-49). RESULTS: An objective response according to the WHO criterias was obselved in 8 patients (53% median duration 10, 5 months), stabilization in 3 and progression in 4 patients. Carcinoid syndrome disappeared in 3 out of 5 cases during 17, 10 and 11 months. CONCLUSION: STZ seems to be more effective than doxorubicin for palliative treatment of liver metastases from digestive endocrine tumors, probably because of the better specificity of this drug for endocrine tumors. 4:00 pm

Ethanol Ablation of Liver Metastasis Attilio Solinas, MD, San Diego, CA • Horacio R. DAgostino, MD. E. Papi, MD. C. Malaspina, MD. P. Roselli, MD • R. Modesto, MD PURPOSE: To evaluate the safety and efficacy of percutaneous ethanol injection (PEI) in the management of liver metastasis. MATERl41S AND METHOD: 31 patients with liver metastasis were assessed by an oncology team and underwent PEl as part of their treatment. Primary malignancies included colorectal carcinoma (20 patients), breast (3 patients), gastric (2 patients), ovarian (2 patients), melanoma (2 patients), prostate (1 patient), and lung cancer (1 patient). All patients had control of their ptimary tumors and no more

than 3 liver lesions. PEl was performed in multiple sessions (27 patients) or a single session under general anesthesia (4 patients, ethanol volume injected 50-120 ml). Treatment response was evaluated by tumor markers levels, dynamic CT and fine needle biopsy. RESULTS: 17 patients were alive with no active liver disease (range 3 to 30 months, median 6 months); 6 patients were alive with persistent liver disease (range 10 to 15 months, median 10 months); 8 patients died from disease progression (range 4-17 months, median 6 months). PEl adverse effects were moderate to severe pain and fever. Tumor markers serum levels and post PEl biopsy results correlated with disease activity. CONCLUSION: PEl was a safe an effective method for ablation of liver metastasis in selected patients.

4:15 pm Percutaneous Hot Saline Injection Therapy: Effectiveness in Chemoembolization-Limited Large Hepatocellular Carcinoma Hyun-Ki Yoon, MD, Seoul, South Korea. Ho-Young Song, MD • Kyu-Bo Sung, MD. Yong-Ho Auh, MD PURPOSE: To report on the efficacy of percutaneous hot saline injection therapy (PSrD in the treatment of chemoembolization-limited large hepatocellular carcinoma (HCC). MATERIALS AND METHODS: Twenty-nine patients with 31 HCCs underwent PSlT. Physiologic saline was mixed with contrast medium and Lipiodol, boiled, and was injected into the tumor. Mean tumor diameter was 7.0 cm. Follow-up computed tomography, angiography, and alpha-fetoprotein level measurement were performed in every three months. Regression rates were analyzed according to the diameter (Group A, <5 cm; Group B, 5-10 cm; Group C, >10 cm), location (central vs. peripheral), and growth pattern (encapsulated vs. infiltrative) of each HCC. RESULTS: The regression rate (RR) for all tumors was 42% (13/31). RRs for group A,B, and C were 86%, 45%, and 15%, respectively (P < 0.05). RRs for centrally and peripherally located tumors were 73% and 25% (p < 0.05). RRs for encapsulated and infiltrative tumors were 48% and 17% (P > 0.05). No major complications were encountered. CONCLUSION: PSlT is a safe and favorable alternative treatment for large HCC when transcatheter arterial chemoembolization is not feasible or has failed.

Wednesday, March 4, 1998 8:00 am-9:30 am Scientific Session 19 Risk Reduction in Diagnostic Angiography Moderator: John A. Kaufman, MD

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Optimizing Imaging Technique for Gadolinium Contrast Angiography David]. Spinosa, MD, Charlottesville, VA. Gary D. Hartwell, DSc • J. Fritz Angle, MD. Klaus C. Hagspiel, MD. SureshJ. Agarwal, PhD. Alan H. Matsumoto, MD PURPOSE: To determine optimal imaging techniques when using gadopentetate dimeglumine as an intravascular contrast agent. MA TERIALS A flow phantom was constructed from plexiglass and contained 3 mm plastic tubing to simulate a blood vessel. A 1 inch aluminum wedge was used to simulate the bony spine. The phantom was submerged in 20 cc of water to simulate a soft tissue environment. A 0.5 mmol/L solution of gadopentetate dimeglumine was infused through the tubing during the image acquisition. An angiography unit with a 40 cm image intensifier and a high resolution digital imaging system was used to obtain DSA images at 2 frames per second. DSA images were obtained at 77 kV, 81 kV, 96 kV, 102 kV, 109 kV, 117 kV, and 125 kV. The amount of gadolinium contrast relative to the background contrast was determined by measuring video signal in mV and reported in percent contrast for each kV. RESULTS: The calculated percent gadolinium contrast at 77 kV, 81 kV, and 96 kV equaled 13%. The calculated percent gadolinium contrast at 102 kV equaled 11%, at 109 kV equaled 9%, at 117 kV equaled 7%, and at 125 kV equaled 5%. The percent contrast at 96 kV was calculated in the presence of a radiation reducing copper filter (0.3 mm) and determined to be unchanged (13%). CONCLUSION The flow phantom model demonstrates that intravascular gadopentetate dimeglumine contrast images are optimized at 77 to 96 kV. DSA images obtained at 96 kV with the addition of a 0.3 mm copper filter should produce optimal contrast while minimizing the radiation dose to the skin of the patient. These results reflect a compromise between the higher k-edge of gadolinium-based contrast and the lower sensitivity of the cesium iodide crystals in the image intensifier at higher kVs.

8:15 am Optimization of Gadolinium Angiography Dominic Carl Yee, MD, Tucson, AZ. Julie Marie Zaetta, MD PURPOSE: To determine adequate gadolinium (Gd) contrast concentration and radiographic technique to perform renal arteriography.

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MATERIALS AND METHODS: A single 20 kg canine underwent repeated abdominal aortic arteriography to evaluate the renal arteries using different concentrations of gadolinium and radiographic technique. The contrast injections were all performed using a

power injector through a 5 Fr. Pigtail catheter with a flow rate of 5 cels for a total volume of 15cc. Gd arteriograms were performed with concentrations of 100% (0.5 mM/ml gadopentetate dimeglumine), 75%, 50%, 25%, and 12.5%. Subsequently full strength Gd arteriograms utiliZing Kvs of 90, 80, 70, 60 were then performed. A control iodine contrast arteriogram using full strength Ioxilan (300mg lim]) was also performed. The images were reviewed and graded by 6 angiographers. Reviewers were asked to rank the images by overall quality. They were then asked which images would be acceptable to rule out a renal artery stenosis greater than 75% and if they were sufficient enough to evaluate the segmental branches. RESULTS: The iodine contrast angiogram was consistently chosen as the best angiogram with the full strength Gd angiogram being second best. 83% of the observers felt 70 Kv to be the best technique for performing Gd angiography. 100% felt that 75% strength Gd was sufficient to evaluate the main renal arteries for stenosis. However, only 50% felt that this concentration of Gd was sufficient for evaluating the segmental branches. CONCLUSION Gadolinium can be used effectively for performing angiograms. The concentration of the Gd may be decreased to 75% when evaluating larger branch vessels of the aorta. In addition, 70 Kv provides the optimal voltage for performing renal angiography. 8:30 am

Gadolinium-Based Digital Subtraction Angiography: Experience in Twenty-one Patients Julie M. Zaetta, MD, Tucson, AZ. Richard A. Baum, MD. ZivJ. Haskal, MD. Michael C. Soulen, MD. Richard D. Shlansky-Goldberg, MD PURPOSE: To evaluate the utility of using gadolinium (Gd) as a contrast agent for digital subtraction angiography (DSA) in patients with renal insufficiency or allergies to iodinated contrast media. MATERIALS AND METHODS: Twenty-one patients underwent gadodiamide (Omniscan) digital subtraction angiography. Indications for gadolinium use included patients with renal insufficiency (17 patients), previous anaphylactic reaction to iodinated contrast agents (3 patients), and current use of metformin HCL (Glucophage) (1 patient). The use of additional contrast agents was at the discretion of the interventionalist. Angiograms were evaluated on a five point scale for diagnostic quality. RESULTS: Fourteen patients had Gd-arteriography, and seven patients had Gd-venography. In ten patients gadodiamide was the sole contrast agent used (Gd-arteriograms-4, Gd-venograms-6). In the remaining eleven cases, Gd-DSA was supplemented with an alternative contrast media. In nine patients the nonionic contrast medium iohexol diluted to 50% was used and in two

patients carbon dioxide was used. Diagnostic quality was variable, but in general detail was least satisfactory with Gd-abdominal aortograms, while those studies obtained on a subselective bases tended to be comparable to standard iodinated contrast angiograms. There were no immediate complications related to the intraarterial administration of gadolinium. CONCLUSION Gadolinium is a useful alternative contrast agent for DSA in patients with renal insufficiency or severe reactions to iodinated contrast medium.

8:45 am Prophylactic Intra-Procedural Hemodialysis in Patients at Risk for Contrast-Induced Renal Failure Darryl Adam Zuckerman, MD, St. Charles, MO • Marcos Rothstein, MD PURPOSE: To detennine the effectiveness of hemodialysis during angiography in preventing the development of contrast-induced acute tubular necrosis. MATERIALS AND METHODS: Twenty-one diabetic patients with underlying renal insufficiency (average baseline serum creatinine 3.4 mg/dlj range 1.9-6.5) underwent arteriography. Average iodine load was 58 grams. Via a temporary venous catheter, hemodialysis was performed in the angiography suite using a hollow-fiber dialyzer (0.8-1.0 square meter membrane) with portable reverse osmosis. Blood flows of 250300 mllmin were used. Dialysis was started 5 minutes prior to the initial administration of contrast and was continued for 45-60 minutes after the final contrast injection. Arterial and venous iodine concentrations were noted during and immediately after the arteriogram and serum creatinines were monitored in the follow-up period. RESULTS: Serum creatinine declined on post-arteriogram day 1 to 2.9 mg/dl, returning to near baseline on day 2 0.3 mg/dO and did not rise subsequently. Effectiveness of dialysis was shown by iodine concentrations which declined by 32% from peak arterial to venous and by an additional 21% as measured on a 5 hour post-procedural assay. No patient in this extremely high-risk group deteriorated into worsening renal failure and acute or permanent dialysis was avoided.

PURPOSE: Prospective evaluation of the incidence of bacteremia associated with invasive radiological procedures. MATERIAL AND METIfODS: Blood cultures were collected from hundred patients (62 men, 38 women; mean age 65 ::':: 14 years) undergoing intraarterial angiography (N = 50), PTA (N = 30), or percutaneous transhepatic biliary drainage (PTBDj N = 20). Blood samples were obtained before the procedure (To), immediately after puncture of the vessel or bile duct (T 1), at the end of the procedure (Tz), and 30 minutes after the end of the procedure (T3 ). RESULTS: The overall rate of bacteremia was 200/0. Diagnostic angiography was associated with a 160/0 rate of temporary bacteremia (no positive T3 samples), PTA with a 270/0 rate (no clinically significant infectious disease), and PTBD with a 100/0 rate (5% cholangitis with septicemia). We isolated: Staphylococcus (S. epidermidis: N = 7, S. spec.: N = 3, S. aureus: N = 1), Streptococcus (N = 2), Propionibacterium acnes (N = 5), E. coli (N = 1), Enterococcus (N = 1), Enterobacter (N = 1), and Clostridium perfringens (N = 1). Despite the patient with cholangitis no patient had an infectious complication. CONCLUSION Bacteremia occurs frequently during invasive radiological procedures. We advocate strictly aseptic procedures and antibiotic prophylaxis in case of stent implantation.

9:15 am The Utility of Hemostatic Collagen Plug Device in Non-Cardiac Angiography Kyran Dowling, MD, Albany, NY. Brian F. Stainken, MD. Gary P. Siskin, MD. Allen Herr, MD. Valerie S. Mandell, MD PURPOSE: The role of collagen plug devices to seal the angiographic arteriotomy in non-cardiac angiography has yet to be defined. The purpose of this study is to retrospectively review our experience with one particulal' collagen plug device to help determine its utility in a Vascular Radiology practice.

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MATERIALS AND METIfODS: The Angio-Seal (Sherwood, Davis & Geck) collagen plug device was used. The device delivers a flat rectangular anchor which is bioabsorbable within the artery; this is sealed with a collagen plug which is deposited outside the artery. All interventional radiology attendings were first trained on an animal sheep model. Success of deployment, coagulation status and heparinization, complications, need for compression and case make-up were evaluated.

Bacteremia Associated With Invasive Radiological Procedures Hans-]oachim Wagner, MD, Marburg, Germany. Heiko Aifke, MD. Martin Hoppe, MD. Klaus ]ochen Klose, MD

RESULTS: The collagen plug device was successfully deployed in 21 out of 22 attempts (950/0). No groin compression was necessary in 19 out of 21 cases (90%). Complications included one 3cm hematoma requiring no further treatment. "Eight cases were perfonned in

CONCLUSIONS: Peri-procedural dialysis may be an effective means to prevent contrast-induced renal failure in high-risk patients undergoing contrast examinations.

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order to continue heparin in an uninterrupted fashion after endovascular interventions. Four cases of multiple trauma were performed to expedite movement of the patient to the operating room. The remaining cases were diagnostic in nature. The average time of deployment was between one to two minutes. CONCLUSIONS: Apparent indications for this particular collagen plug device in a Vascular Radiology practice may include: The need to provide uninterrupted heparin therapy post angioplasty or stent, large sheath utilization, and the need to move patients immediately to surgery or to facilitate movement of patients who will need more diagnostic exams.

Scientific Session 20 Stents - Experimental Studies Moderator: P. Macke Consigny, PhD 8:00 am A Comparison of a Balloon Expandable Stainless

Steel and a Self-Expanding Nitinol Stent Relative to Vessel Size in the Arterial System of the Swine

Animal Model Anthony Charles Venbrux, MD, Baltimore, MD. Adam B. Winick, MD. Philip Rand Brown, DVM. Carol A. Prescott, RN. Carolyn A. Magee, BS PURPOSE: To compare the degree of hyperplasia after percutaneous placement of the balloon expandable Palmaz stent and the self-expanding Nitinol stent relative to vessel size in the iliac arteries of swine. MATERIALS AND METHODS: After baseline angiographic measurements correlated with intravascular ultrasound (IVUS); Palmaz stents (Symphony, Boston Scientific, Medi-tech, Watertown MA) were placed in the iliac arteries of six swine. lVUS was use to determine the stent diameter to within 10-30% oversizing. lVUS and angiography were performed before and after stent deployment, and prior to sacrifice. Two swine were sacrificed at four, two at six, and two at eight weeks after stent deployment. lVUS measurements each included the proximal, mid and distal stent. RESULTS: All stents were successfully deployed. No thrombosis was observed at follow-up. There was no statistical difference between the degree of intimal hyperplasia of the two stent types based on IVUS at four, six and eight weeks. Angiographic measurements showed only statistical difference at the eight week study interval.

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CONCLUSION: Using IVUS as a means of sizing, there is no statistical difference in the degree of intimal hyperplasia of the Palmaz stent and the Nitinol stent in swine iliac arteries.

8:15 am Histopathologic Effects of a Bioabsorbable Vascular Stent in the iliac Arteries of Swine: A Feasibility Study Martin Geza Radvany, MD, Baltimore, MD. Anthony Charles Venbrux, MD. Phillip Rand Brown, DVM. Carolyn Anne Magee, BS PURPOSE: To evaluate the histopathologic effects of a bioabsorbable stent in the iliac arteries of swine. MATERIALS AND METHODS: After baseline angiography, a graft conduit (W.L. Gore, Flagstaff, AZ) was surgically affixed to the aorta. Through this, a metallic stent (Palmaz, Johnson and Johnson, Warren, NJ) was deployed as a control. Bioabsorbable stents, a co-polymer of lactide and caprolactone, (B. Braun Vena Tech Inc, Evanston, Il) were deployed in the iliac arteries of six swine. Heparin was administered to all animals during stent deployment and aspirin post deployment to 3/6 swine. Angiography was performed after stent placement and before sacrifice (l day to 10 weeks). RESULTS: Nine bioabsorbable stents were deployed in six animals. No occlusive thrombus was identified in either group. light microscopy demonstrated minimal inflammatory response. The neo-intima of the bioabsorbable stents consisted of organized thrombus rather than de novo proliferation and migration of subintimal myofibroblasts seen with metallic stents. Angiographically, lumen narrowing was significantly reduced in the aspirin treated group. CONCLUSION: Bioabsorbable stents do not induce the same type of intimal hyperplasia as is seen with metallic stents. This is reduced with aspirin. Bioabsorbable stents cause only minimal inflammatory response. 8:30 am

Prevention of Neointimal Hyperplasia by Taxol Lindsay Machan, MD, Vancouver, BC, Canada. Pierre Signore, PhD. Peter Bromley, MD. Bill Hunter, MD PURPOSE: To evaluate the ability of a slow release polymer containing taxol to prevent neointimal hyperplasia after balloon injury or stent insertion. MATERIAL AND METHODS: Balloon injury was created in the left common carotid artery of 70 Wistar rats. The remaining 60 were randomized into groups of 10 each immediately receiving a wrap of EVA film, EVA film/20% taxol, PCl paste, PCl pastel20% taxol, PCl block, or PCl block!20% taxol applied directly to the adventitia of the injured artery. 5 animals from each group were sacrificed at 14 or 28 days post balloon injury. Taxol coated metallic stents were inserted into the iliac artery of 6 domestic swine. Three were sacrificed at 4 weeks, three at 8 weeks.