Endovascular treatment of abdominal aortic aneurysms with narrow aortic bifurcation using Excluder bifurcated stent grafts.

Abstract

This study investigated the influence of the aortic bifurcation anatomy on the endovascular treatment of abdominal aortic aneurysms using Excluder (W. L. Gore & Associates, Flagstaff, Ariz) bifurcated stent grafts. This was a retrospective single-center study of patients treated with the Excluder stent graft. Analysis included anatomical factors of the aortic bifurcation (aortic bifurcation diameter [ABD], calcification, thrombus), characteristics of the stent graft limbs (sum of stent graft limbs diameters [SLD]), and the SLD/ABD ratio. Narrow bifurcation was defined as ABD <20 mm. Primary outcomes were intraoperative stenosis, need for additional intraoperative measures, limb stenosis, and occlusion during follow-up. The study included 232 patients. Mean ABD was 24.6 ± 6 mm, with 53 patients (23%) presenting with narrow bifurcation (range, 12.5-19.5 mm). Median SLD in these patients was 28 mm, and the SLD/ABD ratio was 1.64. Calcification involving >50% of the bifurcation circumference was present in 32% of the patients, with 17% presenting thrombus in this area. Of 53 patients with narrow bifurcation, intraoperative stenosis >50% occurred in three (5.7%), which required adjunctive treatment. Computed tomography at 1 month showed limb stenosis >50% in nine patients (17%). No limb occlusions were recorded with a median follow-up of 34 months. Multivariate analysis of the overall series showed a higher risk of limb stenosis on the computed tomography at 1 month in patients with peripheral artery disease (hazard ratio [HR], 5.3; 95% confidence interval [CI], 1.2-24.4; P = .032), narrow bifurcation (HR, 5.7; 95% CI, 2-15.8; P = .001), higher SLD/ABD ratio (HR, 29.3; 95% CI, 4-215.2; P = .001), and calcium >50% (HR, 3; 95% CI, 1.1-8; P = .03), and lower in bifurcations with thrombus (HR, 0.3; 95% CI, 0.1-0.8; P = .017). Abdominal aortic aneurysms with narrow bifurcation can be treated with the bifurcated Excluder device without additional adjunctive measures. The presence of limb stenosis during follow-up is not associated with occlusion. Long-term follow-up studies are needed to confirm these results.