Long-term Results of Endovascular Aortic Aneurysm Repair According to the Instructions for Use

Background: Endovascular aortic repair (EVAR) is considered the first therapeutic option in patients with abdominal aortic aneurysms and favorable anatomy due to the advantages in terms of lower perioperative complications and faster recovery compared to open repair, even in high-risk patients. These advantages, together with technical improvements, convinced vascular surgeons to adopt EVAR also in challenging anatomies, sometimes crossing the limit of the manufacturer’s instructions for use (IFU). Objectives: Few data are available on how adherence to IFU may affect early and long-term outcomes of EVAR, for this reason, a single-center retrospective analysis has been conducted. Materials and methods: All patients with an abdominal aortic aneurysm and indication to treatment according to current guidelines who underwent EVAR between January 2018 and December 2023 were enrolled. Fenestrated EVAR or branched EVAR or patients with connective tissue disease were excluded. Patients were divided into two groups: those who were treated according to endograft’s IFU and those who did not completely satisfy the IFU. The primary endpoints were the long-term survival, the incidence of aortic-related death, aortic-related re-interventions, and the increase of the aneurysm’s sac diameter of more than 5 mm. Results: 140 patients (97,9% males) with a median age at analysis of 77 years were involved; 132 patients had an abdominal aortic aneurysm, 6 patients had a right iliac artery aneurysm, and 2 had a left iliac artery aneurysm. The average maximal aneurysm diameter was 57,56 mm. Among the early outcomes, 3,5% of patients had a pulmonary complication: 80% of these were part of the Outside of IFU group. 1,4% of patients had a stroke: they were of the Outside of IFU group. 4,2% of patients (3 within IFU, 3 outside of IFU) underwent reintervention, either because of thromboischemic events or to correct an endoleak type 1. Finally, 1,4% of patients (1 within IFU, 1 outside of IFU) died: one because of COVID pneumonia, and one because of multi-system organ failure from the aneurysm rupture. With a mean follow-up of 16 months, the overall survival rate was 95,6%, 89%, and 89% at 1, 3, and 5 years respectively for the Within IFU patients and 89,8%, 87,7%, and 87,7% at 1, 3, and 5 years for the Outside of IFU patients, without statistical difference. The aortic death-free survival rate was 3,3%, 7,7%, and 13,2% at 1, 3, and 5 years respectively for the Within IFU patients and 6,1%, 6,1%, and 8,2% at 1, 3, and 5 years for the Outside of IFU patients, without statistical difference. The reintervention rate was 95,6%, 89%, and 89 % at 1, 3, and 5 years respectively for the Within IFU patients and 89,8%, 87,7%, and 87,7% at 1, 3, and 5 years for the Outside of IFU patients, without statistical difference. No difference was found in terms of aneurysm sac growth between the two groups. Conclusions: This study confirms EVAR as a safe and effective tool for the treatment of AAA, even with complex anatomies. In contrast with the literature, patients undergoing EVAR outside IFU have similar late survival and reintervention rates. Despite these favorable outcomes, accurate patient selection and strict follow-up are strongly recommended for this cohort of patients.