Preservation of hypogastric flow and control of iliac aneurysm size in the treatment of aortoiliac aneurysms using the Nellix EndoVascular Aneurysm Sealing endograft

Abstract

The purpose of this study was to determine the long-term effectiveness of endovascular aneurysm sealing (EVAS) in the treatment of complex aortoiliac aneurysms with preservation of hypogastric artery flow. We reviewed all patients with abdominal aortic aneurysms (AAAs) and common iliac aneurysms (CIAs) enrolled and treated in prospective studies of EVAS using the Nellix endograft (Endologix, Irvine, Calif) at two centers from 2008 to 2014. Patients with 1year or more of computed tomography follow-up underwent quantitative morphometric assessment by two independent vascular radiologists blinded to clinical outcome results. Hypogastric patency and CIA diameter changes over time were assessed and compared in three treatment groups: totally excluded CIA, partially excluded CIA, and untreated CIA. Among 125 patients with EVAS, 68 patients (mean age, 75± 8years; 79% men) had both AAA (mean diameter, 55.8± 2.0mm) and CIA (median diameter, 23.4; interquartile range, 21.3-27.0mm), with bilateral CIAs in 33 patients. Treatment of 101 CIAs included complete CIA exclusion in 40 (39.6%), partial CIA exclusion in 33 (32.7%), and no CIA treatment in 28 (27.7%), with successful AAA exclusion in all patients. Internal iliac flow was preserved in all 122 hypogastric arteries that were patent before treatment (14 hypogastric arteries were occluded at baseline). During the 5-year follow-up period (median follow-up, 24.7months; range, 11.5-61.7months), three patients required secondary treatment with hypogastric occlusion and graft extension to the external iliac. Thus, internal iliac flow was maintained in 98% of at-risk hypogastric arteries. There were no aneurysm-related clinical events, except for the three secondary treatments. Totally excluded iliac aneurysms did not change in diameter over time (P= .85), whereas untreated CIAs enlarged at a rate of0.16mm/y (95% confidence interval, 0.09-0.23; P< .0001). Partially excluded CIAs enlarged at a higher rate of 0.59mm/y (95% confidence interval, 0.47-0.71; P< .0001). Enlargement ≥3mm occurred only in partially treated CIAs larger than 3cm. EVAS was effective in treating aortoiliac aneurysms with preservation of internal iliac patency in most cases. Complete CIA exclusion prevented aneurysm enlargement over time, whereas partial exclusion did not prevent continued CIA enlargement, particularly in larger aneurysms.