Objective risk-scoring systems for repair of abdominal aortic aneurysms: applicability in endovascular repair?

Recent studies propose the use of objective risk-scoring systems as a clinical tool for selecting patients for open or endovascular abdominal aortic aneurysm repair (EVR). The aim of this study was to evaluate four established risk-scoring systems for accuracy of prediction of early mortality and morbidity following EVR.

266 consecutive patients undergoing elective EVR at St. George's Vascular Institute between July 2001 and January 2007 were studied using a prospective database. The Glasgow Aneurysm Score (GAS), the Vascular Physiology and Operative Severity Score for the enUmeration of Mortality and Morbidity (V-POSSUM), the modified Customised Probability Index (m-CPI) and the Customised Probability Index (CPI) were applied for prediction of 30-day mortality and morbidity. Accuracy of prediction was compared using receiver operating characteristics (ROC) curve analyses.

30-day mortality and morbidity rates were 4% (11/266) and 8% (22/266) respectively. For prediction of mortality, GAS, V-POSSUM, m-CPI and CPI ROC curve analyses showed areas under the curves (AUCs) of 0.68 (95% confidence interval (CI), 0.48-0.87; p=0.046), 0.66 (95% CI, 0.51-0.81; p=0.067), 0.63 (95% CI, 0.45-0.81; p=0.148) and 0.65 (95% CI, 0.49-0.80; p=0.101) respectively. Corresponding AUCs for prediction of morbidity were 0.64 (95% CI, 0.51-0.76; p=0.511), 0.62 (95% CI, 0.51-0.74; p=0.505), 0.54 (95% CI, 0.41-0.67; p=0.416) and 0.55 (95% CI, 0.42-0.68; p=0.451).

GAS, V-POSSUM, m-CPI and CPI were poor predictors of early mortality and morbidity following EVR in this series. Caution should be applied to the use of these scoring systems for pre-operative risk stratification and treatment selection for endovascular repair of abdominal aneurysms.