Midterm outcomes of aneurysm repair with the Cook Zenith Alpha abdominal endovascular graft

Abstract

Objective: Outcome reports after endovascular aneurysm repair (EVAR) using the low-profile Zenith Alpha Abdominal Endovascular grafts (Cook Medical, Bjæverskov, Denmark) are sparse. We present results from a single-center cohort treated with the Zenith Alpha, from a period where the graft was the primary EVAR device choice. The aim of the study was to evaluate short- and midterm outcomes of patients treated with the Zenith Alpha.

Methods: A retrospective single-center study was performed including all patients treated with the Zenith Alpha graft from October 1, 2015 to September 30, 2018. All patients underwent computed tomography angiography (CTA) imaging preoperatively as well as at 3 and 12 months postoperatively. Hereafter, patients were followed yearly with duplex ultrasound and clinical exams. Additional imaging was performed on indication. All CTAs were analyzed using three-dimensional reconstruction software (Aquarius, TeraRecon, Durham, NC). Data was extracted from electronic charts according to a protocol that remained unchanged until the end of the study (December 31, 2020). The following outcomes were assessed according to Society for Vascular Surgery/International Society of Cardiovascular Surgeons reporting criteria: aortic-related and all-cause mortality, reinterventions, instruction for use (IFU) violations, endoleaks (ELs), and aneurysm shrinkage.

Results: A total of 241 patients were treated with the Zenith Alpha, and 214 (89%) were asymptomatic repairs. Technical success was achieved in 238 patients (99%). One hundred fifty-seven patients (65%) received implantation outside IFU. The median hospital length of stay was 2 days (interquartile range, 2-3 days). The median clinical follow-up was 35.1 months (interquartile range, 28.8-47.5 months). The 4-year Kaplan-Meier estimate of freedom from reintervention was 66% (95% confidence interval, 59%-73%). The main reasons for reinterventions were iliac limb stenosis and occlusion (n = 30; 12%) and type 2 EL (n = 13; 5%). Overall, significantly more patients with grafts implanted outside distal IFU developed type 1B ELs (n = 10/11; P = .009). Aneurysm sac shrinkage was observed in 48 patients (25%) 1 year postoperatively. The Kaplan-Meier estimate of freedom from aortic-related mortality was 99% (95% confidence interval, 98%-100%) 4 years postoperatively.

Conclusions: EVAR with the Zenith Alpha shows acceptable freedom from aortic-related mortality up to 4 years postoperatively. The majority of patients were treated outside IFU, and significantly more type 1B ELs appeared in this subgroup of patients. The leading cause for reintervention was impaired limb patency. The root cause for impaired limb patency requires further investigation.

Keywords: Abdominal aortic aneurysm; Endovascular aneurysm repair; Zenith Alpha abdominal endovascular graft.