Prognostic model for survival of patients with abdominal aortic aneurysms treated with endovascular aneurysm repair

Abstract

The role of endovascular aneurysm repair (EVAR) in patients with asymptomatic abdominal aortic aneurysm (AAA) who are unfit for open surgical repair has been questioned. The impending risk of aneurysm rupture, the risk of elective repair, and the life expectancy must be balanced when considering elective AAA repair. This retrospective observational cohort study included all consecutive patients treated with standard EVAR for AAA at a referral centre between 2001 and 2020. A previously published predictive model for survival after EVAR in patients treated between 2001 and 2012 was temporally validated using patients treated at the same institution between 2013 and 2020 and updated using the overall cohort. 558 patients (91.2% males, mean age 74.9 years) were included. Older age, lower eGFR, and COPD were independent predictors for impaired survival. A risk score showed good discrimination between four risk groups (Harrel's C = 0.70). The 5-years survival probabilities were only 40% in "high-risk" patients, 68% in "moderate-to-high-risk" patients, 83% in "low-to-moderate-risk", and 89% in "low-risk" patients. Low-risk patients with a favourable life expectancy are likely to benefit from EVAR, while high-risk patients with a short life expectancy may not benefit from EVAR at the current diameter threshold.

Figure 1

Study Cohort. Follow-up period is reported by median and quartiles (Q1–Q3). 5 years-Survival is reported with median and 95% confidence intervals. FUI = Follow-up Index.

Figure 2

Survival Curves of Predictive Score. Kaplan–Meier Estimators with corresponding 95% confidence interval for overall survival stratified by risk score. Log-rank test was used to compare difference in survival.

Figure 3

Predictive Score. Predictive score based on the Cox proportional hazard model presented in Table 4. Adding the points from Age, COPD and KDIGO gives a total score that determines the risk category. COPD: chronic obstructive pulmonary disease; KDIGO: kidney function as estimated glomerular filtration rate according to the “Modification of Diet in Renal Disease Study” equation.