Factors Affecting Survival after Endovascular Aneurysm Repair: Results from a Population Based Audit

Objectives To determine the effect of pre-operative factors on mid-term survival of patients enrolled in an Australian audit of endovascular aneurysm repair (EVAR). Design Prospective longitudinal national register (audit) of patients undergoing EVAR. Methods 961 individuals who had elective or semi-urgent EVAR of abdominal aortic aneurysms were enrolled in the audit between November 1999 and May 2001. Data was contributed by 81 surgeons from 64 hospitals. Kaplan-Meier survival analysis was used to determine survival rates and factors significantly influencing survival. Parametric survival analysis with log-exponential distribution was used to estimate expected 3 and 5 year survival for different ages, ASA, creatinine and aneurysm sizes. Results Overall survival was 93% at 1 year, 80% at 3 years and 67% at five years. Survival rates were found to be statistically associated with ASA, age, aneurysm size and creatinine levels. ASA has the largest effect. Five year survival rates for aneurysms ≥65 mm and <55 mm were 54% and 76% respectively. Pre-operative creatinine levels ≥ 160 μmol/L lowered the survival rate from 71% to 40%. Conclusions Survival for EVAR patients is strongly correlated with a number of pre-operative factors. This survival analysis provides a useful decision-making tool for surgeons particularly for individuals with smaller aneurysms.