Validation of the European system for cardiac operative risk evaluation II in a large Taiwan cardiac surgical centre

Background: The European System for Cardiac Operative Risk Evaluation (EuroSCORE II) is a well-established scoring system for predicting mortality in cardiac surgery. This system was derived predominantly from a European patient cohort; however, no validation of this system has been conducted in Taiwan. We sought to assess the performance of EuroSCORE II at a tertiary centre. Methods: The 2161 adult patients receiving cardiac surgery between 2017 and 2020 in our institution were included. Results: Overall, the in-hospital mortality rate was 7.89%. The performance of EuroSCORE II was assessed using the area under the receiver operator curve (AUC) for discrimination and the Hosmer–Lemeshow (H–L) test for calibration. Data were analysed for type of surgery, risk stratification, and status of the operation.EuroSCORE II had good discriminative power (AUC=0.854, 95% Confidence Interval (CI): 0.822–0.885) and good calibration (χ2=5.19, p=0.82) for all types of surgery except ventricular assist devices (AUC=0.618, 95% CI: 0.497–0.738). EuroSCORE II also showed good calibration for most types of surgery except coronary artery bypass surgery (CABG) combined procedure (P=0.033), heart transplantation (HT) (P=0.017), and urgent operation (P=0.041). EuroSCORE II significantly underestimated the risk for CABG combined procedure and urgent operations, and overestimated the risk for HT. Conclusion: EuroSCORE II had satisfactory discrimination and calibration power to predict surgical mortality in Taiwan. However, the model is poorly calibrated for CABG combined procedure, HT, urgent operation, and, likely, lower- and higher-risk patients.