Bilateral Endograft Limb Occlusion after Endovascular Aortic Repair: Predictive Factors of Occurrence.

Background: Bilateral limb occlusion after endovascular aortic repair (EVAR) is relatively uncommon. The aim of this study was to investigate the incidence of bilateral endograft limb occlusion after EVAR and identify potential anatomical predictive factors of occurrence.
Methods: A total of 579 patients underwent elective EVAR for abdominal aortic aneurysm between January 2010 and December 2015. All patients presenting with unilateral and bilateral occlusions were prospectively analyzed. A group of patients who underwent EVAR but did not present with endograft limb occlusion were matched for sex, age, and commercial type of endograft and were used as controls.
Results: Overall, 21 (3.6%) patients were complicated with unilateral endograft limb occlusion, whereas 8 (1.4%) of them presented with sequential (in different time) bilateral limb occlusion. We found that iliac artery angulation ≥60°, iliac perimeter calcification ≥50%, and endograft oversizing in the common iliac artery of more than 15% had the same impact and could equally result in limb occlusion. We coded the variables angle, calcification, and endograft limb oversizing of the common iliac artery with a score from 0 to 2 as follows: (1) 0: angle <60° in both limbs, 1: angle ≥60° in one limb, 2: angle ≥60° in both limbs; (2) 0: calcification <50%: in both limbs, 1: calcification ≥ 50%: in one limb, 2: calcification ≥ 50%: in both limbs; and (3) 0: endograft limb oversizing <15%, 1: endograft limb oversizing ≥15% in one limb, 2: endograft limb oversizing ≥15% in both limbs. A composite variable, consisting of the sum of scoring in variables was analyzed, with a score from 0 to 6. Our study showed that it was the most probable to be in the control group when score in the composite variable was 0-3, it was the most probable to have unilateral limb occlusion when score was 4-5, and finally, it was the most probable to have bilateral limb occlusion when score in the composite variable was equal to 6.
Conclusions: Our study evidenced that the highest probability for bilateral limb occlusion occurred when implantation of a more than 15% oversized endograft in iliac arteries with iliac artery angulation ≥60° and iliac perimeter calcification ≥50% was present in both iliac arteries. It is therefore clear that limb occlusion requires the synergistic effect and interaction of bilateral multiple thrombogenic components in the iliac artery before it is manifested.
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