Systematic review and meta-analysis of outcomes after semi-conversion with graft preservation for failed endovascular aneurysm repair

Abstract

Objective: The aim of this study was to evaluate the outcomes after semi-conversion (open conversion with graft preservation) after failed endovascular aneurysm repair (EVAR). The primary outcomes were 30-day mortality and semi-conversion failure. Secondary outcomes were 30-day major systemic complications, endoleak recurrence, reinterventions, and overall survival.

Methods: The review followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. The protocol was prospectively registered on PROSPERO (CRD42023421153). All studies reporting the outcomes of semi-conversions for failed EVAR were eligible for inclusion. Quality assessment was performed using the Methodological Index for Non-Randomized Studies (MINORS) tool. A random effects meta-regression of proportions was conducted using the double arcsine-Tukey transformation, given the frequent zero event rate in the primary outcome. Heterogeneity was assessed with the I² statistic.

Results: Eight studies were included in the review after full text screening. A total of 196 patients underwent semi-conversion at a mean time from EVAR of 47.4 months, 68.9% in an elective setting. Mean age at conversion was 78.1 years, and the main indication was isolated endoleak type II (70.1% of cases). Aortic clamping was not necessary in 92.3% of semi-conversions; the aortic sac was opened in 96.1% of cases; in 93.3% of cases, ligation/suture of one or more culprit arteries were performed; and aortic neck banding was executed in 29.2%. At 30 days from surgery, the pooled mortality and the major systemic complications rates were 5.3% (I² = 24.9%) and 13.4% (I² = 54.3%), respectively. At follow-up, endoleak recurred after 12.6% semi-conversions (I² = 83.2%), and the rate of reinterventions was 7% (I² = 50.1%); the semi-conversion failure rate was 5.5% (I² = 54.1%), and the overall survival was 84.6% (I² = 33.3%).

Conclusions: Semi-conversions have acceptable 30-day mortality rates, but the early and mid-term risks of complications, reinterventions, ruptures, and infections are not negligible. This procedure might be an alternative to complete or partial graft explant in patients whom aortic cross-clamping is not ideal.

Keywords: Abdominal aortic aneurysm; Endovascular procedures; Failed endovascular aneurysm repair; Meta-analysis; Reinterventions; Semi-conversion; Systematic review.