Performance of EuroSCORE II and logistic EuroSCORE in Bangladeshi population undergoing off-pump coronary artery bypass surgery: A prospective cohort study

Abstract

Introduction: European System for Cardiac Operative Risk Evaluation (EuroSCORE) was developed to identify patients who may have a greater postoperative risk for adverse effects following adult cardiac surgery. This study evaluated the discriminatory potential of using the EuroSCORE system in predicting the early, as well as late, postoperative outcomes following coronary artery bypass graft surgery in Bangladesh.

Methods: A total of 865 patients who underwent isolated coronary artery bypass graft surgery were evaluated with the EuroSCORE risk scoring system. Moreover, we also compared the discriminatory potentials between the EuroSCORE II and the original logistic EuroSCORE.

Results: Operative mortality was best predicted by EuroSCORE II (area under the curve (AUC) 0.863, Brier score 0.030) compared to the original logistic EuroSCORE (AUC 0.849, Brier score 0.033). However, the overall expected-to-observed mortality ratio for EuroSCORE II was 1.1, whereas the observed ratio for the original logistic EuroSCORE was 1.7. EuroSCORE II was predictive of an intensive care unit stay of five days or more (AUC 0.786), prolonged inotropes use (AUC 0.746), stroke (AUC 0.646), de novo dialysis (AUC 0.810), and low output syndrome (AUC 0.715). Moreover, a high EuroSCORE II quintile significantly predicted the risk for late mortality (p < 0.0001).

Conclusions: EuroSCORE has an important role in predicting the early, as well as late, postoperative outcomes following coronary artery bypass surgery. However, the performance of EuroSCORE II is significantly better than the original logistic EuroSCORE in predicting postoperative morbidity and mortality after isolated coronary artery bypass graft surgery among Bangladeshi patients.

Keywords: EuroSCORE II; coronary artery bypass graft; ischemic heart disease.

Figure 1.

Observed and predicted operative mortality rates according to the original logistic European system for cardiac operative risk evaluation (EuroSCORE), and EuroSCORE II according to quintiles of the EuroSCORE II. Early mortality represents postoperative 30-day mortality.

Figure 2.

Line diagram demonstrating the predicted-to-observed operative mortality ratio between the EuroSCORE II, and the original logistic EuroSCORE. However, EuroSCORE II has a prediction of optimal performance in the third highest quintiles.

Figure 3.

Major postoperative adverse events according to the quintiles of the European system for cardiac operative risk evaluation II (EuroSCORE II).

Figure 4.

Overall survival rate after coronary artery bypass graft surgery, according to EuroSCORE quintiles (EuroSCORE II) by Kaplan–Meier estimation curve. Note: Log-rank test p-value < 0.0001.