Frailty Remains Highly Correlated With Mortality After Endovascular Aneurysm Repair in Octogenarians

Abstract

The elective treatment of asymptomatic abdominal aortic aneurysm must be balanced with individual life expectancy, which can be difficult to estimate. Frailty can help estimate perioperative risk, but most scales are heavily weighted by patient age. The objective of this study was to assess how frailty affects the outcomes of those with advanced age (≥80 years) undergoing endovascular aneurysm repair (EVAR). The Vascular Quality Initiative EVAR module was queried for all patients ≥80 years who underwent elective EVAR. A previously validated frailty model, the modified frailty index (mFI), was used to calculate a score for each patient. The mFI scores were calculated both with and without age as a variable. Low-, moderate-, and high-risk groups were created on the basis of the 0 to 25th, 26th to 75th, and 76th to 99th percentile distributions of the score across the study cohort. Logistic and Cox proportional hazards models were built using mFI score as a continuous variable. Of 9780 patients older than 80 years undergoing elective EVAR, 8462 (87%) had sufficient data to calculate the mFI. The mFI scores ranged from 26 to 56 with a median of 31. Low frailty corresponded to mFI score of <30; moderate frailty, 30 to 34; and high frailty, ≥35. There was no difference between groups in intraoperative complications or early reoperation. Among the low, moderate, and high frailty groups, the rates of early postoperative complications (7%, 7.1%, and 10%; P = .003) and 30-day mortality (0.8%, 1.1%, and 2.7%; P < .001) were higher in the highest frailty group. One-year mortality increased across the low (4%), moderate (6.8%), and high (13.6%) frailty groups (P < .001). An unadjusted Cox proportional hazards model yielded a hazard ratio of 1.09 (95% confidence interval, 1.08-1.1), representing a 9% increase in mortality hazard for every 1-point increase in mFI score. Kaplan-Meier survival curves by frailty group are shown in Fig 1. When frailty scores were calculated independently of age, postoperative complications and mortality were unchanged between groups as shown in Fig 2. A validated, easily calculable frailty index is strongly associated with perioperative and 1-year mortality among patients ≥80 years undergoing EVAR. In low-frailty octogenarians, EVAR is safe with low postoperative morbidity and mortality. Despite being the most heavily weighted component of the mFI, age adds little or no prognostic value past 80 years old.Fig 2View Large Image Figure ViewerDownload Hi-res image Download (PPT)