Scientific Session 24 Venous Thrombolysis

CONCLUSIONS: These data, from both in vitro and in vivo studies, suggests that the proliferative response in TIPS is not primarily due to bile leak.

1:45 pm Comparison of Polyethelene Teraphthalate (PET) Covered Wallstents Versus Uncovered Wallstents for TIPS Creation in an Animal Model Ziv Haskal, MD, Philadelphia, PA PURPOSE: To evaluate the safety and efficacy of a polyethelene teraphthalate (PET) covered Wallstent for TIPS creation in an animal model. MATERIALS AND METHODS: Thirteen TIPS were created in 13 minipigs: 8 lined with PET-covered Wallstents (water permeability: 750-2000 cc/cmjeP2/min), 5 with standard Wallstents. Shunt venography was performed at 5-8 weeks, necropsy at 7-8 weeks. Histology, immunohistopathology, and electron microscopy was performed on the explants. RESULTS: The devices proved equally easy to deploy. At 7-8 week venography, the mean shunt stenoses of the control and graft groups were 45% (range 26-83%) and 53% (range 0-90%), respectively. There was 1 graft TIPS occlusion. All stenoses developed within the liver tract. One stenosis was due to trans-stent proliferation of normal porcine liver tissue. Typical myofibroblast and collagen matrix proliferation encompassed both control and graft TIPS. There was no evidence of bile staining within this tissue. A neointima of varying thickness lined the lumina in both groups. Slightly more pronounced inflammation was present at the graft ends (site of PET material fixation). CONCLUSION This TIPS stent-graft is easy and safe to place. Its healing response and patency, in this specific animal model, are similar to bare stent TIPS. 2:00 pm

Percutaneous Retroperitoneal Splenorenal Shunt: An Experimental Study in Swine Toshio Kaminou, MD, PhD, Portland, OR. Barry T. Uchida, BS. ShOji Sakaguchi, MD • Dusan Pavcnik, MD, PhD. Hans A. Timmermans, BFA. Frederick S. Keller, MD

PURPOSE: To evaluate percutaneous retroperitoneal splenorenal shunt (PRESS) in swine, which potentially can be a new minimal invasive treatment of portal hypertension. MATERIAL AND METHODS: Eight domestic swine underwent PRESS. A modified TIPS puncture set was introduced from the right femoral vein into the left renal vein. The proximal splenic vein was punctured. A Wallstent and a PTFE covered stent-graft were then placed connecting both veins through the retroperitoneal cavity. The animals were followed up weekly by splenic venography until the shunt occluded.

RESULTS: Puncture of the splenic vein and stent placement was successfully completed in all cases. In seven of eight animals, good flow from the splenic vein to the left renal vein through the shunt tract was observed one hour after PRESS. No changes in vital signs were noticed during the procedure. Five of eight tracts showed obstruction one week after PRESS. At necropsy minimal retroperitoneal hematoma along the tract were found. Stents and stent grafts were positioned in the retroperitoneal cavity connecting both veins in all cases. Remarkable intimal hyperplasia with clots was present in the tracts. CONCLUSIONS: Creation of a percutaneous splenorenal shunt is technically possible and further experimental studies of its efficacy are warranted.

2:15 pm Portal Vein Embolization for Extension of Hepatectomy Indications Thierry de Baere, MD, Villejuif, France. Alain Roche, PhD. Dominique Elias, MD. Philippe Lasser, MD PURPOSE: To render hepatectomy feasible in patients with an initially deficient volume of the future remnant liver (FRL). MATERIALS AND METHODS: Portal blood flow was redistributed towards the FRL with preoperative embolization of the portal veins (POPE) feeding the future resected liver. POPE was performed in 38 patients with malignant tumors and in 2 with benign lesions. POPE was performed under fluoroscopic guidance, via a percutaneous transhepatic access to the portal vein. RESULTS: FRL volume values were 90-560 cc (m = 271 cc) before POPE and 160-933 cc (m = 455 cc) after POPE, which represents a volume increase of 83 ± 49%. Hypertrophy of the FRL was 92% ± 62% after 31 days with Cyanoacrylate, 53% ± 6% after 43 days with Gelfoam, and 44 ± 30% after 35 days with coils. Slight shrinkage was obtained in the volume of the embolized liver. POPE was well tolerated and surgery was possible in 32 patients. Seven operations were cancelled due to tumor spread, but only one due to insufficient hypertrophy of the FRL. CONCLUSION Although exclusively applicable in a limited subset of patients, POPE widens the possibilities of curative hepatectomies, because it induces hypertrophy of unembolized liver segments. Among embolic materials, cyanoacrylate seems to ensure better and faster hypertrophy.

Scientific Session 24 Venous Thrombolysis Moderators: Martin Richard Crain, MDj Julien 1. Struyven, MD

201

1:00 pm lleo-Femoral Venous Thrombosis Treated With Catheter Directed Urokinase Infusion james W. jaffe, MD, Allentown, PA • james A. Newcomb, MD PURPOSE: To report our seven-year experience with catheter directed thrombolysis of ileo-femoral D.V.T. via direct passage of the catheter into affected veins. MA1ERIALS AND MElliODS: Forty-six patients with pWegmasia and documented ilio-femoral thrombosis were treated. Thirty patients were catheterized via contralateral retrograde approach and sixteen patients were catheterized via antegrade popliteal puncture. The catheter was advanced into the clot and infusion of urokinase was used (mean dose 5.6 million units). Nine patients received a metal iliac stent following lysis. RESULTS: Forty-five patients demonstrated greater than 50% lysis and significant resolution of symptoms, with decreased pain, swelling and improvement in limb status. One pulmonary embolus occurred, and no bleeding complication was encountered. At a mean follow-up of 12.5 months, six patients have manifested Class I venous insufficiency; the remaining are asymptomatic.

CONCLUSION Catheter directed thrombolytic therapy used for symptomatic relief of phlegmasia has a high initial success rate with minimal complications. This technique may decrease the rate and severity of post-pWebitic syndrome, however, long term follow-up is needed, as well as comparison to other modalities for symptomatic DVT.

1:15 pm Thrombolytic Treatment for lliofemoral Deep Vein Thrombosis Using Catheter-Directed Delivery: Intermediate Results Haraldur Bjarnason, MD, Minneapolis, MN. janice R. Kruse, RD. Charles A. Dietz, MD. Michael S. Rosenberg, MD. David W Hunter, MD PURPOSE: Present our experience and determine the venous patency rates after treating IFDVT. MA1ERIALS AND MElliODS: Ninety-two patients (104 limbs) were treated with catheter-directed thrombolysis using Urokinase. Symptom duration was one week in 56 limbs, 1-4 weeks in thirty-six limbs, and more than 4 weeks in 12 limbs.

202

RESULTS: The immediate success rate was 87% for thrombi less than 4 weeks old (92 limbs) and 50% for thrombi older than 4 weeks (12 limbs). The average duration of symptoms before treatment was 16 days. The average treatment time was 3 days and 4 hours (8-247 hours) with an average of 11,000,000 (440,00024,000,000) Lu. of urokinase used. Few complications occurred. Metal stents were placed in 45 limbs (98 stents). Patency was defined. The overall two year pri-

mary patency for iliac veins was 60% and the secondary patency rate was 80%. CONCLUSION Catheter-directed thrombolysis is a safe & effective treatment for acute iliofemoral venous thrombosis. The age of the thrombus is an important prognostic factor as well as concurrent malignant disease. Patency rates are acceptable for 2 years post-treatment.

1:30 pm Optimization of Thrombolytic Therapy for lliofemoral Deep Vein Thrombosis: Algorithm for Endovascular Treatment Charles P. Semba, MD, Stanford, CA. Marina Haugland, BA • Stephen T. Kee, MD. Mahmood K. Razavi, MD. Suzanne M. Slonim, MD. Michael D. Dake, MD PURPOSE: To assess the relationship of thrombolysis and duration of clinical symptoms of deep vein thrombosis (DVT) and devise a treatment algorithm. MATERIALS AND MEmODS: 52 patients (26M: 26F; mean age, 46 yrs) with iliofemoral DVT underwent catheterdirected thrombolysis using urokinase (120-180 K units/ hr). The subsequent endovascular management following initial thrombolytic therapy was analyzed retrospectively. RESULTS: A total of 55 limbs were treated (39 L: 16 R). The success of initial (::::;24 hrs) thrombolysis and mean duration of DVT symptoms were as follows: complete (n = 8), 1.2 wks; partial (n = 27), 4.6 wks; none (n = 20), 85.7 wks. Four management patterns were identified: (1) complete lysis and no stenosis-no further therapy (n = 2), (2) complete lysis with stenosis-angioplasty/stent (n = 6), (3) partial lysis-continue lysis for 24 hrs (n = 27), (4) no lysis-no further urokinase; angioplasty and!or stent (n = 16). Patients with no thrombolysis and occluded femoral and iliac veins were considered technical failures (n = 4).

CONCLUSION The effectiveness of initial thrombolytic therapy is dependent on duration of symptoms and is not recommended for symptoms >6 weeks. An endovascular algorithm is proposed based upon findings of follow-up venography after initial thrombolysis.

1:45 pm lliofemoral Deep Vein Thrombosis: Assessment of Patency and Venous Valvular Reflux Following Catheter-Directed Thrombolysis Charles p. Semba, MD, Stanford, CA. Peter T. Beatty, MD. Stephen T. Kee, MD. Mahmood K._Razavi, MD. Giallian McFarlane, RN. Michael D. Dake, MD PURPOSE: Catheter-directed thrombolysis for iliofemoral deep venous thrombosis (DVT) has been used as an alternative to anticoagulation. Functional studies to assess intermediate term patency and venous reflux following catheter-directed thrombolysis were performed. MATERIALS AND MElliODS: 26 patients (M 14: F 12; mean age, 47.3 yrs) underwent catheter-directed throm-

bolysis for iliofemoral DVT in 28 limbs (L = 17, R = 9, both = 2) using continuous infusion of urokinase. Infusion catheters and/or guidewires were placed directly into the thrombus using popliteal, femoral, and/or jugular venous access. Doppler assessment of valvular reflux and venous patency were performed immediate post-procedure, at 6-8 weeks, 3, 6, and 12 months. RESULTS: Thrombolysis was complete in 15 (54%), partial in 9 (32%) and no lysis in 4 limbs (14%). Iliac PTA and stents were required in 20 (71%); PTA only in 3 limbs (11%). The mean follow-up period was 5.8 months (range, 1 week-12 months). Primary patency was 93%and reflux was identified in 14%. All failures occurred within 6 to 8 weeks following treatment. CONCLUSION: Catheter-directed thrombolysis is a viable altemative to anticoagulation in preserving venous patency and function for iliofemoral DVT. 2:00 pm

Treatment of Clinically Symptomatic Upper Extremity Venous Thrombosis With CatheterDirected Thrombolysis and Intervention Reed Ali Omary, MD, Chicago, IL. Howard Brett Chrisman, MD. Albert A. Nerncek, Jr., MD. Robert Lee Vogelzang, MD PURPOSE: To assess the efficacy of thrombolysis and intervention in treating symptomatic upper extremity venous thrombosis.

MATERIALS AND METHODS: Using the HI_IQTM system database, we retrospectively reviewed all symptomatic patients who received thrombolysis over the last 4 years. Twenty-four patients (8M, 16F; mean age 48y), with 29 symptomatic extremities, received therapy. Duration of symptoms ranged from 2 days to 6 months. All patients had involvement of subclavian and/or brachiocephalic veins, of had extension into the superior vena cava. Isolated superior vena cava involvement was excluded. All received transcatheter infusion of urokinase with the dose ranging from 60,000 to 250,000 IU/hour and duration of infusion ranged from 10 hours to 98 hours. Heparin therapy was also utilized. Additional intervention was performed in 13 of 29 extremities (45 percent) (12 PTLA, 4 stents, 1 thrombectomy device). RESULTS: Immediate angiographic and clinical improvement was noted in 24 of 29 (83 percent) symptomatic extremities. Of the 5 patients with no clinical or angiographic improvement, 3 patients (10 percent) had urokinase terminated early due to complications and 2 (7 percent) were unresponsive due to chronic occlusion. Six minor complications (21 percent) (4 bleeding, 1 heparin induced thrombocytopenia, 1 hypofibrinogenemia) and no major complications occurred. CONCLUSION: Acutely symptomatic upper extremity thrombolysis can be safely and effectively treated with

transcatheter thrombolysis and intervention. Chronic occlusions are less effectively treated.

2:15 pm Lack of Acute Injury to Venous Valves by the Amplatz Thrombectomy Device During Experimental Antegrade Venous Thrombectomy Melhern]A. Sharafuddin, MD, Iowa City, L4. Xiaoping Gu, MD. Myra Urness, BS. Kurt Amplatz, MD PURPOSE: To evaluate the acute effects of using the Amplatz thrombectomy device (ATD) across peripheral venous valves in a canine model.

MATERIALS AND METHODS: Bilateral saphenous vein segments (diameter 4.0 ± 1.6 mm) where used in 5 adult dogs. Access was established retrogradely (descending) on one side, and antegradely (ascending) on the opposite side. The ATD was activated and advanced in a back-and-forth motion (mean activation time: 30 ± 25 sec), never engaging more than minimal resistance. Following euthanasia, segments harboring the valves were evaluated grossly and histopathologically. RESULTS: In ascending procedures, the ATD was advanced for 15 ± 5 cm, whereas in descending procedures, it could only be advanced for 5 ± 5 cm. Gross post-mortem examination showed no significant injury to the walls or valves in any of the veins, regardless of the direction of AID advancement. Histopathologically, the lEL was intact and continuous from the vein wall to the smooth-luminal and rough-parietal surfaces of the valve in all specimens. Mild focal mural hemorrhage was noted at the base of one valve in one specimen, corresponding to the location of the introducing sheath. CONCLUSION: The AID caused no significant acute morphologic injury to the walls and valves of target veins, even when advanced retrogradely. Nevertheless, the possibility of delayed valve dysfunction was not assessed. Retrograde advancement of the ATD against the valves was very difficult in small veins.

Thursday, March 5, 1998 8:00 am-9:30 am Scientific Session 25 CT Angiography Moderator: Kevin Dickey, MD 8:00 am

Asymmetric Growth of Aortic Aneurysms: Imaging and Pathological Correlation David M. Williams, MD, Ann Arbor, MI. Isaac R. Francis, MD. Gerald D. Abrams, MD. Charles]. Shanley, MD. Thomas W. Wakefield, MD. G. Michael Deeb, MD

203