Iliac Limb Occlusion Research Articles

Endovascular management of iliac limb occlusion of bifurcated aortic endografts

Although aortic endograft iliac limb occlusion is an uncommon event, its treatment is problematic because standard surgical thrombectomy risks graft dislodgment or component separation. Although femorofemoral bypass grafting can restore perfusion to the affected limb, its longevity may be inferior to reestablishing patency of the endograft itself and represents a failure of the endograft procedure. With aortic endografts now commercially available, implanting surgeons must be aware of this important complication and well versed in all of the endovascular treatment options. We report three cases of endoluminal management of unilateral iliac limb occlusion of bifurcated aortic endografts.

Impact of Unilateral Common Iliac Vein Occlusion on Trapping Efficacy of the Greenfield Filter: An in Vitro Study

Rationale and Objectives The purpose of this study was to assess the effect of unilateral common iliac vein occlusion on the capturing efficacy of the Greenfield filter in vitro. Materials and Methods A stainless steel over-the-wire Greenfield filter was placed in the Silastic inferior vena cava module of a pulsatile circuit. Three 30-mm blood clots in sets of five were injected through the module's right iliac limb with the circuit in four experimental conditions: vertical position, both iliac limbs patent (VP); vertical position, left iliac limb occluded (VOC); horizontal position, both iliac limbs patent (HP); and horizontal position, left iliac limb occluded (HOC). Each experiment was repeated 15 times, resulting in 75 clots per condition and a total of 300 clot introductions. Results Clot trapping efficacy was 36 of 75 (48%) for VP, 41 of 75 (55%) for VOC, 32 of 75 (43%) for HP, and 26 of 75 (35%) for HOC. Cross comparisons of the four conditions revealed a marginally significant difference ( P = .0138 with a corrected test-wise α = .0125) only between horizontal and vertical positions with unilateral common iliac limb occlusion. Conclusion Unilateral common iliac vein occlusion decreases the capturing efficacy of the Greenfield filter in the horizontal position in vitro. In patients with unilateral common iliac vein occlusion, use of inferior vena cava filters with higher capturing efficacy may be considered.

Endovascular Treatment of Iliac Limb Stenoses or Occlusions in 31 Patients Treated with the Ancure Endograft

The authors report their experience with treatment of iliac limb complications in patients treated with the Ancure endograft with Wallstents to provide additional support and thrombolysis when needed. From February 1996 to October 1999, 88 patients were treated for abdominal aortic aneurysm with use of the Ancure endograft. Of the 88 devices used, 20 were tube grafts and the remaining 68 devices had a total of 130 iliac limbs (bifurcated, n = 62; aortoiliac, n = 6). After graft deployment, all patients underwent intraoperative aortography; since July 1997, intravascular ultrasound (IVUS) has also been used. Thirty-one patients (46%) required treatment of 47 (36%) limbs with Wallstents. Graft narrowing was observed in 41 limbs (27 patients) with IVUS immediately after graft deployment. All were successfully treated with placement of Wallstents. Before routine use of intraoperative IVUS, three patients presented between 2 and 6 weeks postoperatively with iliac limb thrombosis. All three limbs were successfully treated with thrombolysis and Wallstent placement to correct the underlying iliac problem. Additionally, two contralateral limbs in these three patients were also noted to have stenosis and were treated with use of Wallstents. The last patient required placement of a Wallstent to treat stenosis of surgical anastomosis of the iliac limb of an aortoiliac endograft at 3 days. All Wallstent-reinforced Ancure endografts remained patent from 1 to 36 months (mean, 14 months). After placement of an Ancure bifurcated or aortoiliac endograft, iliac limb stenosis is easily detected with use of intraoperative IVUS. Such complications can be safely corrected with Wallstent placement. Postoperative limb occlusion at the authors' institution has been eliminated with such intervention.

Evaluation of a modular endovascular bifurcation prosthesis in a canine aortic aneurysm model.

The study evaluated the deployment and healing of a novel self-expanding modular bifurcation endovascular prosthesis in a canine abdominal aortic aneurysm model. The endoluminal prosthesis consists of self-expanding nitinol stents lined by a synthetic prosthesis. One component of the device is a bifurcated body with a 12- to 14-mm diameter aortic segment and an integral 7- to 8-mm diameter iliac limb. The bifurcated body also has a stent-reinforced opening (pant-leg) for subsequent insertion of a contralateral 7- to 8-mm diameter iliac limb component. Seventeen bifurcated prosthesis were placed; 7 were inserted through the left common carotid artery and 10 from the femoral arteries. With either route of access the 16F or 17F aortoiliac limb and the 13F iliac limb delivery catheters enabled easy passage and secure positioning of the bifurcated prostheses. Predeployment and postdeployment inspection of the dimensions and continuity of the aortoiliac prosthetic components were evaluated by cinefluoroscopy and intravascular ultrasonography (IVUS). After deployment was done, interval patency was assessed with angiography, IVUS, and contrast-enhanced computed tomography with the prostheses removed for analysis at 1 week (n = 4), 1 month (n = 3), 3 months (n = 4), and 6 months (n = 6). Five of the first seven implanted prostheses had occlusion of segments of the device. In two dogs the bifurcated body and both legs were occluded. In the other three the nonoccluded leg and bifurcation body were fully patent. In the first seven animals IVUS at implantation showed compression of an iliac leg by the orifice of the contralateral iliac component. After concentric fixation of the flow divider was performed, only one additional iliac limb occlusion occurred in the next 10 animals. Cinefluoroscopy, computed tomography, IVUS imaging, and histologic analysis of retrieved specimens demonstrated healing of the aortoiliac prostheses without evidence of perigraft leaks. This feasibility study demonstrates the ability to deploy and maintain acceptable patency of a self-expanding endoluminal, modular bifurcation prosthesis in a canine aortic model. Clinical evaluation of the device is planned for the near future.