Survival and Reintervention Risk by Patient Age and Preoperative Abdominal Aortic Aneurysm Diameter after Endovascular Aneurysm Repair

Abstract

Endovascular aneurysm repair (EVAR) has become the standard of care for abdominal aortic aneurysm (AAA), but questions remain regarding the benefit in high-risk and elderly patients. The purpose of this study was to examine the effect of age, preoperative AAA diameter, and their interaction on survival and reintervention rates after EVAR. Our integrated health system's AAA endograft registry was used to identify patients who underwent elective EVAR between 2010 and 2014. Of interest was the effect of patient age at the time of surgery (≤80 vs.>80 years old), preoperative AAA diameter (≤5.5cm vs.>5.5cm), and their interaction. Primary endpoints were all-cause mortality and reintervention. Between-within mixed-effects Cox models with propensity score weights were fit. Of 1,967 patients undergoing EVAR, unadjusted rates for survival at 4years after EVAR was 76.1%, and reintervention-free rate was 86.0%. For mortality, there was insufficient evidence for an interaction between age and AAA size (P=0.309). Patient age >80 years was associated with 2.53-fold higher mortality risk (hazard ratios [HR]=2.53; 95% confidence intervals [CI], 1.73-3.70; P<0.001), whereas AAA > 5.5cm was associated with 1.75-fold higher mortality risk (HR=1.75; 95% CI, 1.26-2.45; P=0.001). For reintervention risk, there were no significant interactions or main effects for age or AAA diameter. Age and AAA diameter are independent predictors of reduced survival after EVAR, but the effect is not amplified when both are present. Age >80years or AAA size >5.5cm did not increase the risk of reintervention. No specific AAA size, patient age, or combination thereof was identified that would contraindicate AAA repair.