Scientific Session 17: Thrombolysis 1

patients undelwent nine embolization procedures without complication. Follow-up CT showed complete resolution of perigraft flow in five patients; one patient awaits follow-up CT. CONCLUSIONS: Although perigraft flow commonly is seen initially with the EVT-EGS, persistent leak occurs in 12% of patients. Persistent flow in most patients arises from a graft attachment site combined with patent outflow vessels, including the lMA or lumbar arteries. Persistent perigraft flow can be safely embolized using a combination of coil embolization of the perigraft space and embolization of outflow vessels. Long-term outcome of such intervention is still unknown.

associated with postprocedural buttock claudication. This complication usually is not observed in patients who do not have aortic endografts and may be related to exclusion of the lumbar arterial collaterals.

Tuesday, March 23, 1999 1:00 pm-2:30 pm Scientific Session 17 Thrombolysis 1 Moderator: Karim Valji, MD 1:00 pm

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Abstract No. 96

Preprocedural Internal Iliac Artery Embolization Prior to Endovascular Repair of Abdominal Aortic Aneurysm Jeffrey E. Saavedra, MD, San Francisco, CA • Robert K. Kerlan, Jr., MD. Mark W. Wilson, MD. Jeanne M. laBerge, MD. Roy L. Gordon, MD. Ernest j. Ring, MD PURPOSE: To evaluate the frequency, efficacy, and complications of preprocedural embolization of internal iliac arteries before endovascular treatment of abdominal aortic aneurysms. MA TERlALS AND METHODS: Eighty-five patients underwent endovascular repair of an abdominal aortic aneurysm with a Chuter endograft. Six of these patients had preoperative unilateral embolization of the internal iliac artery. Indications for embolization included: (1) associated internal iliac artery aneurysm, (2) common iliac artelY aneurysm that would prevent endovascular seal, and (3) abnormally shOl1 «3 cm) common iliac artery, which would make accurate deployment of the distal endograft into the common iliac artery difficult. Embolizations of the internal iliac arteries were performed with a combination of O.018-inch platinum microcoils and O.035-inch steel coil spring emboli. No particulate embolic material was used. All patients underwent follOW-Up contrast-enhanced spiral computed tomography to assess for the presence of postprocedural endoleak in addition to periodic clinical evaluation. RESULTS: Successful embolizations were achieved in all patients. Postprocedural computed tomography confirmed successful occlusion of the internal iliac artery in all six patients. One of the six patients had a postprocedural endoleak related to an incomplete proXimal seal and a large patent lumbar artery. All six patients developed significant buttock claudication on the side of the embolization. In two patients, the claudication was extremely disabling, preventing effective ambulation. In all patients, however, the claudication resolved within 6 months.

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CONCLUSION Internal iliac artery embolization is effective in the prevention of endoleaks but is frequently

Abstract No. 97

FEATURED ABSTRACT Commentator: Michael Golden, MD Local Overexpression of Thrombomodulin for In Vivo Prevention of Arterial Thrombosis Jacob M. Waugh, MD, tan/ord, CA. Michael D. Kuo, MD. Eser Yuksel, MD.]ia j. Li, PhD. Michael D. Dake. MD. Savio L.G. Woo, PhD PURPOSE: These experiments have been designed to limit intra-arterial thrombus formation through local over xpr ion of thrombomodulin. Endothelial thrombomodulin play a critical role in hemostasis by binding thrombin and sub equemly converting protein C to its active form, a powerful anticoagulant. Thrombomodulin thus represents a central me hallism by which patency is maintained in normal v s. I '. However, thrombomoduHll expression decreases in perturbed endothelial cells, predisposing to thrombotic occlusion. Gene therapy offer a method of sustained high-levelthrombomodulin expression even in pelturbed vessel'. MATERIALS AND l\1fE1HODS: An adenoviral constru t expressing lhrombomodulin (Adv/RSV-THM) was created and functionally charact rized in vitro and in vivo. The impact of Local ov rexpees. ion of thrombomodulin on in vivo thrombus formation was subsequently examined in a stasis/injury mod I of anerial lhrombosi . Briefly, rabbit conunon femoral arteries were u'ea-ted with burrer, viral control, or Adv/R VT.HM, then divided and reanaStomo d with an intraluminal stasis element introduced 5 mm down.sU"eam. RE ULTS: The con u'uet prevented arterial thrombosis formation in all animal, while viral and nonviral controls developed occluding thrombi. By histologic analy is, oonviral cOlltrols exhibited intravascular thrombus occluding a mean of 7052% :!: 3.72% of available lumen, while viral control reached 86.85% :!: 2.82% thrombotic occlusion; in contrast, A 1 /RSVTHM reduced thrombo i' to 28.61% :!: 3.31% of lumen in efOSS-S ctiOll. 0 signiftcant intima to media

raLio was ob rved in the thrombo01odulin group relative to comrols. Local infiltration of granulocytes and macrophage significantly decreased in the Advl RSV-THM group relative to conu'ols, willie neutrophilic infiltration increased in viral controls relath'e to nOllvira.l comrols. CONCLUSION: This construct thu' offers a viable technique for promoting a locally thromboresistant small-caliber artery, without the inflammatory damage that has limited many other adenoviraJ applications. 1:15 pm

Abstract No. 98

Evaluation of an Intramural Drug Delivery Catheter for Local Thrombolysis Sumit Roy, MB, BS, MD, Oslo, Nonvay. hade Laemm, MD, PhD. Frank Brosstad, MD, PhD. Knut Kvernebo, MD, PhD. Kjell S. Sakariassen, PhD PURPOSE: To assess in a porcine model of acute deep vein thrombosis (DVT) the potential utility of the nipple balloon catheter for local thrombolysis. MATERIALS AND METHODS: [n 10 pigs, DVT was induced in both hind limbs by a preViously described method. Thirty minutes later, the animal was heparinized and bilateral thrombolysis was performed using tPA 8 mg (0.25 mglml + heparin 50 U/ml). In one limb a 4.3F nipple balloon catheter was used. The enzyme was delivered as 0.4-mJ boluses with the balloon inflated. After each bolus, the balloon was deflated and catheter position changed. On the opposite side, "sequestration" thrombolysis was performed. The external iliac vein was endoluminally occluded and a multi-sideport infusion guidewire placed in the thrombosed veins. tPA was administered as 0.8-ml boluses every 3 minutes. At autopsy, the thrombus mass in the femoral veins was measured, and the extent of residual thrombosis in the venous tributaries was graded at four sites. RESULTS: Over a guidewire, the trackability of the nipple balloon catheters through thrombosed veins was satisfactory and the balloons tolerated multiple inflationl deflation cycles. Without exception, thrombus mass was lower in the test limbs (p = 0.005). The median value was 0.13 g (95% CI: 0.02, 0.30) as compared to 0.34 g (0.25, 0.69) in the controls. The superiority of the nipple balloon catheter was less clearcut in the venous tributaries. 1n 8/10 and 9/10 animals, respectively, the degree of residual thrombosis in the superficial femoral vein tributaries and the popliteal vein was equal to or less than in the controls. For the pudendoepipoic and profunda femoris veins, however, the cOlTesponding figures were 7/10 and 5/10. No macroscopic damage to the veins was observed. CONCLUSIONS: The use of the nipple balloon catheter was associated with a higher therapeutic efficacy than

"sequestration" thrombolysis in our animal model. A preliminary clinical evaluation of the device would seem warranted. 1:30 pm

Abstract No. 99

Utility of Heparin Substitutes in Transcatheter Management of Acute Deep Vein Thrombosis Sumit Roy, MB, BS, MD, Oslo, Nonvay. Frode Laerum, MD, PhD. Frank Brosstad, MD, PhD. Knut Kvernebo, MD, PhD. Kjell S. Sakariassen, PhD

PURPOSE: To assess in a porcine model of acute deep vein thrombosis (DVT) whether a factor Xa antagonist (dalteparin) or a selective thrombin antagonist (antithrombin) offers any benefit over heparin during selective thrombolysis. MATERIALS AND METHODS: DVT was induced in both hind limbs by a preViously described method. Thirty minutes later, the animal was heparinized (2500 IU IV) and bilateral "sequestrated" thrombolysis was performed: both external iliac veins were endoluminally occluded with Swan-Ganz catheters, and a multi-sideport infusion wire was coaxially introduced through each catheter and advanced into the ipsilateral popliteal vein. Tissue plasminogen activator (tPA) 8 mg was injected as 0.8-mJ boluses at 3-minute intervals for 2 hours as a 0.25-mglml solution. In one limb, the enzyme solution was supplemented with either dalteparin 50 U/ml (n = 5) or antithrombin 12.5 U/ml (n = 5). In the opposite limb, heparin 50 IU/mJ was substituted. At autopsy, the thrombus mass in the femoral veins was measured, and the extent of residual thrombosis in the venous tributaries graded at four sites. RESULTS: Antithrombin: The thrombus mass in the limbs exposed to antithrombin was higher than in the controls in all animals (p = 0.04). However, the differences were modest, with the median increase being only 9% (range: ZO/()-86%). The degree of residual thrombosis in the peripheral veins was similar in the two groups. Dalteparin: Median thrombus mass in the dalteparin group was 0.34 g (0.05-1.07 g) as compared to 0.35 g (0 12-0.56 g) in the controls (p = 0.7). The response of thrombosis in the tributaries was essentially the same irrespective of whether heparin or dalteparin was used. CONCLUSIONS: Neither dalteparin nor antithrombin proved to be superior to heparin for local therapy. With the latter, the efficacy of thrombolysis was indeed somewhat lower. 1:45 pm

Abstract No. 100

Long-Term Follow-Up After Percutaneous Hydrodynamic Thrombectomy in Lower Limb Arteries with Acute Lower Limb Ischemia Stefan Muller-Hulsbeck, MD, Kiel, Germany. Marc Kalinowski, MD. Hans Wagner, MD

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PURPOSE: To evaluate the long-term efficacy of the hydrodynamic thrombectomy device AngioJet in patients with acute lower limb ischemia. MATERIALS AND METHODS: From May 1995 to December 1997, 112 patients (56 men, 56 women, mean age 71.2 years) were primarily treated with the thrombectomy catheter. Ninety-nine native arteries and 16 bypass grafts were occluded with a mean occlusion length of 16.3 em. Fifty-one lower limbs were deemed viable, 61 threatened, and 3 irreversible (SVS criteria). The cause of occlusion was a thrombosis in 79 cases and an embolus in 36 cases. Adjunctive procedures to restore patency were PTA (61%), suction thrombectomy 00%), stent implantation (9%), and local fibrinolysis 08%). Primary patency rates, mortality rates, limb salvage rates, and amputation-free survival rates were calculated according to SVS criteria. Patients were followed with clinical examination, ankle-brachial index, treadmill test, and color-coded duplex sonography and angiography in case of reobstruction. RESULTS: The mean follow-up for all patients was 14.8 months:±: 11.5 months. The Kaplan-Meier life table analysis yielded a I-year primary patency rate of 68%, amputation-free survival rate of 81%, and mortality rate of 11%. After 3-year follow-up the primaly patency rate was 59%, amputation-free survival rate 68%, and mortality rate 19%. CONCLUSION The long-term results of the hydrodynamic thrombectomy device are comparable to the results of other treatment modalities for acute lower limb ischemia, such as Fogarty thrombectomy or local intraarterial fibrinolysis.

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Abstract No. 101

Thrombolytic Administration in a Non-Intensive care Unit Setting: One Year Experience David 1. Waldman, MD, Rochester, NY. Rodoljo Queiroz, MD. David E. Lee, MD. Roy K. Sumida, MD • Kenneth Ouriel, MD. Richard M. Green, MD PURPOSE: To assess the safety of thrombolytic administration in a non-intensive care unit setting.

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MATERiALS AND METHODS: At the University of Rochester Medical Center, clinical guidelines were created for thrombolytic therapy administration outside the intensive care unit. A dedicated vascular floor was established for the care of these patients. Using the High IQ T~ system data base, we retrospectively reviewed all patients receiving thrombolytic therapy over 2 years. July 1996 through 1997 (group I) was retrospectively compared to July 1997 through July 1998 (group II). From 1996 through 1997, thrombolytic therapy was administered in an intensive care unit. The policy was changed in July 1997. The primary endpoint was complications. Major complications were defined as bleeding requiring transfusion, intracranial hemorrhage, or any complication re-

quiring additional hospitalization. Minor complications were defined as any bleeding not requiring transfusion, or any symptoms thought to be related to urokinase administration, although not requiring therapy or increased hospitalization. RESULTS: There were 54 patients in group I and 67 in group n. No intracranial hemorrhage was seen in either of the two groups. Five major complications (9.3%) were seen in group I and six major complications (8.9%) in group II. One patient died of pneumonia not thought to be related to urokinase administration. Both groups had a minor complication rate of approximately 14%, with 8 minor complications seen in group I and 10 seen in group II. CONCLUSION Urokinase can safely be administered on a dedicated vascular floor. This can substantially reduce the cost of thrombolytic therapy. Nursing education and strict clinical guidelines are required for this type of program.

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Abstract No. 102

Avoiding the Complications of Thrombolysis Steven M. Thomas, MRCP, FRCR, Sheffield, United Kingdom. Peter Gaines, MRCP, FRCR PURPOSE: NATALI is a voluntary data base of patients undergoing peripheral vascular thrombolysis run on behalf of the TSG. The size of the data set allows analysis to identify predictors of outcomes and complications. These may be patient factors or related to the technique used. MATERiALS AND METHODS: Since its inception on Jan. 1, 1990, 798 thrombolysis events have been recorded. Details are collected on a wide range of factors: perceived risk factors, details of thrombolysis technique, complications, outcome, an.d adjunctive procedures. Using univariate and multivariate analysis, factors associated with an increased risk of complications were investigated . RESULTS: Death and complications perilysis occurred in 25.9% (n = 207) of cases. Patient factors were the main influence on the risk of complications. Increasing age, use of aspirin, and thrombolysis of grafts were significantly associated with an increased risk of complications after adjustment for confounders (p < 0.05). Female sex, the presence of peripheral vascular disease, and Fontaine class were of borderline Significance. Other patient factors were not associated with any increased risk of complication. Radiologic technique, such as agent used, sheath size, length of lysis, dose of lysis, use of heparin or adjunctive procedures, had no relationship to the rate of complications. CONCLUSION Case selection is the most important factor influencing the occurrence of complications. Radiologic technique does not seem to influence the occurrence of complications.