Predicting outcomes following open abdominal aortic aneurysm repair using machine learning

Patients undergoing open surgical repair of abdominal aortic aneurysm (AAA) have a high risk of post-operative complications. However, there are no widely used tools to predict surgical risk in this population. We used machine learning (ML) techniques to develop automated algorithms that predict 30-day outcomes following open AAA repair. The National Surgical Quality Improvement Program targeted vascular database was used to identify patients who underwent elective, non-ruptured open AAA repair between 2011 and 2021. Input features included 35 pre-operative demographic/clinical variables. The primary outcome was 30-day major adverse cardiovascular event (MACE; composite of myocardial infarction, stroke, or death). We split our data into training (70%) and test (30%) sets. Using 10-fold cross-validation, 6 ML models were trained using pre-operative features with logistic regression as the baseline comparator. Overall, 3,620 patients were included. Thirty-day MACE occurred in 311 (8.6%) patients. The best performing prediction model was XGBoost, achieving an AUROC (95% CI) of 0.90 (0.89-0.91). Comparatively, logistic regression had an AUROC (95% CI) of 0.66 (0.64-0.68). The calibration plot showed good agreement between predicted and observed event probabilities with a Brier score of 0.03. Our automated ML algorithm can help guide risk-mitigation strategies for patients being considered for open AAA repair to improve outcomes.