Relative Survival after Abdominal Aortic Aneurysm Repair: The Impact of Competing Non-aortic Mortality.

Abstract

This study investigated long term survival following endovascular aortic repair (EVAR) or open surgical repair (OSR) for abdominal aortic aneurysm (AAA), with a relative survival analysis using an age and sex matched population cohort. This was a retrospective single centre cohort study of patients who underwent AAA repair at a tertiary hospital between June 1998 (OSR from July 2003) and December 2022. Death was obtained from a linked national database, with cause of death identified from electronic hospital records. Maximum aortic diameter and sex were used to estimate the rupture risk over 3 years compared with observed all cause and categorised mortality. Kaplan-Meier probability estimates compared the survival following AAA repair with an age and sex matched New Zealand population cohort. In this study, 1 066 patients underwent EVAR (915 men, 151 women) and 218 patients (169 men, 49 women) underwent OSR. The thirty day mortality rate was 0.84% following EVAR and 6.0% following OSR. The median survival post-EVAR was 7.9 years (95% confidence interval [CI] 7.5 - 8.5), compared with 8.0 years (95% CI 7.0 - 9.7) post-OSR, and 14 years (95% CI 13.2 - 15.2) in an age and sex matched New Zealand population, with survival probability following AAA repair lower by 14% at 3 years and 25% at 5 years compared with the matched cohort. During follow up 673 EVAR patients (63.1%), and 168 OSR patients (77.1%) died, most commonly due to malignancy, respiratory, cardiac, or neurological disease. Aortic related death accounted for 2.8% of the EVAR cohort and 4.8% of OSR deaths. The estimated three year cumulative rupture risk, had repair not been performed, was 5.9% (95% CI 4.4 - 7.7%). Over 24 years, patients undergoing AAA repair demonstrated significantly lower medium and long term relative survival compared with an age and sex matched population cohort, with most deaths attributable to non-aortic causes. Long term survival following EVAR and OSR was similar. While contemporary rupture risk appears lower than historically reported, the predominance of competing non-aortic death underscores the importance of individualised patient selection and consideration of projected life expectancy when selecting patients for intervention.