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.Methods
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.Results
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).Conclusions
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.