Anatomic and clinical characterization of the narrow distal aorta and implications after endovascular aneurysm repair

Abstract

Objective: The purpose of this analysis was to compare 1-year clinical outcomes after endovascular repair of abdominal aortic aneurysms with the EXCLUDER device in patients with standard and narrow aortic bifurcations (AOBs).

Methods: Data were prospectively collected from a 1055-participant subset of the multicenter Global Registry for Endovascular Aortic Treatment (GREAT) treated for abdominal aortic aneurysm repair between August 2010 and September 2015. There were 117 patients with a narrow AOB (NB; defined as <16 mm) and 938 patients with a standard bifurcation (SB). The 30-day and 1-year morbidity, mortality, and reintervention outcomes were analyzed, with Kaplan-Meier survival curve analysis conducted on freedom from mortality and freedom from reintervention.

Results: The mean distal aortic neck diameter was 12.4 mm in the NB cohort and 25.3 mm in the SB cohort (P < .001), with NB patients also exhibiting significantly smaller diameter proximal aortic necks (P < .001). Patients in the NB cohort were more often female (25.6% vs 15.1%; P = .004) and with more severe comorbidity burden. There was a significantly higher rate of surgical cutdown access in the NB cohort (P < .001). Procedural survival was 100% in both groups. The 30-day mortality and safety outcomes were similar; however, all-cause mortality was significantly higher in the SB cohort through 1 year (P = .02). The 1-year freedom from mortality was estimated as 92.1% in the SB cohort and 99.1% in the NB cohort. Freedom from reintervention was estimated as 95.1% in the SB cohort and 92.8% in the NB cohort at 1 year. Through 1-year follow-up, 24 SB patients (2.6%) and 4 NB patients (3.4%) exhibited an endoleak requiring reintervention (P > .99). Type II endoleaks represented 72% and 60% of treated endoleaks, respectively. Through 1 year, 10 SB patients (1.0%) and 2 NB patients (1.7%) exhibited occlusive/thrombotic events (P = .54). There were no reported instances of kinking, migration, fracture, compression, or dissection through 1 year in either cohort. One SB patient experienced thoracic aortic aneurysm rupture.

Conclusions: The 1-year outcomes after endovascular aneurysm repair with the EXCLUDER device were comparable in the NB and SB cohorts. A narrow AOB was not found to be associated with a higher incidence of later limb occlusions or endoleaks. Female patients were disproportionately more likely to have a narrow AOB, which correlated with narrowed proximal necks and access vessels, and a more severe comorbidity burden.

Trial registration: ClinicalTrials.gov NCT01658787.

Keywords: Distal aorta; EVAR; EXCLUDER; Limb occlusion; Narrow bifurcation.

Copyright © 2018 Society for Vascular Surgery. Published by Elsevier Inc. All rights reserved.