Patients with Ruptured Abdominal Aortic Aneurysm Have Become Higher Risk.

Background: Independent risk factors such as age, loss of consciousness, elevated serum creatinine, low hemoglobin, and electrocardiogram evidence of ischemia have previously been shown to predict mortality after ruptured abdominal aortic aneurysm (rAAA). With an aging Australian population, we sought to determine if patients presenting with rAAA now had more predictive risk factors for mortality and whether these factors remain predictive of mortality.

Methods: The records of all patients presenting with rAAA between January 1985 to December 1993 (past era, group 1) and January 2007 to December 2011 (modern era, group 2) were retrieved. A database of independent risk factors, repair method, and mortality was constructed. Comparisons were made between the 2 groups, where a P value of < 0.05 was considered statistically significant.

Results: Hundred and eighty-eight patients presented with rAAA in the past era, of which 154 were then prepared for repair. 60 patients presented in the modern group, in which 38 patients were then prepared for repair. Proportionally, more patients in the modern era group were rejected for surgery compared to the past era group, (22/60 vs. 34/188; P = 0.004) Rejection was based on both medical comorbidities as well as patient/family and surgeon preferences. The in-hospital mortality rate for patients undergoing repair remained unchanged between the groups at 39%. Age was the only predictive factor that differed between the modern and past era groups (median age: 81 vs. 72 respectively, P < 0.001). However, this equated to more risk factors per patient in the modern group compared to the past era (2 vs. 1, respectively, P < 0.001). When stratified by 0, 1, 2, and 3 + risk factors present, there was a trend toward lower mortality in the modern group per strata. Univariate and multivariate analysis of the risk factors in the modern group demonstrated that low blood hemoglobin was the only risk factor independently predictive of mortality in the modern group.

Conclusions: Patients in the modern era group are older and presenting with more predictive risk factors for mortality after rAAA. This has seen an increased rate of rejection for surgery. However, mortality rates following rAAA repair remain unchanged. These results suggest that the previously identified predictive risk factors need to be adjusted.