Derivation and Validation of Predictive Index of Morbidity and Mortality in Abdominal Aortic Aneurysm (AAA) Repair; A Customized Risk Scoring Index For Abdominal Aortic Aneurysm Patients

Objectives: Scoring systems have evolved to quantify patient's risk by utilizing various data. The purpose of this study is to analyze three established surgical scoring systems and subsequently construct and validate a predictive risk scoring system for morbidity and mortality in AAA surgery.
Methods: Lee Revised Operative risk score, EuroSCORE and V-POSSUM were applied retrospectively to 114 elective AAA repair patients from November 2001 to November 2005. Receiver Operative Characteristic (ROC) curves compared discriminative properties of each index. Subsequently multiple logistic regression was applied to multiple variables. Each variable was tested for significance, with those of non-significance being eliminated. Weighted scores based on their co-efficients were then applied to produce a predictive equation. ROC analysis was then applied to this equation to objectively assess accuracy.
Results: V-POSSUM and EuroSCORE overestimated mortality. However, there was significant association between predicted and observed mortality (p<0.05). Sensitivity rates were low (V-POSSUM = 52.4%, EuroSCORE = 38.3%) with high specificity (93.07% and 96.8% respectively). ROC curve analysis indicated greater predictive accuracy of EuroSCORE (0.735 +/- 0.031) compared to V-POSSUM (0.601 +/- 0.048). Twelve variables were found to be significant in AAA risk assessment, which when applied to the developmental equation produced excellent predictive accuracy (ROC 0.7875 +/- 0.036).
Conclusions: In light of new Techniques to high risk patients, Open & Emergency repair is becoming an adverse event Customised index provides more detailed information than POSSUM, EuroSCORE, Lee index about the type of AAA Repair, clinical risk factors with a greater predictive accuracy of morbidity and mortality.