Assessment of the EuroSCORE risk scoring system for patients undergoing coronary artery bypass graft surgery in a group of Iranian patients

Abstract

Background and Aims: Previous studies around the world indicated validity and accuracy of European System for Cardiac Operative Risk Evaluation (EuroSCORE) risk scoring system we evaluated the EuroSCORE risk scoring system for patients undergoing coronary artery bypass graft (CABG) surgery in a group of Iranian patients. Materials and Methods: In this cohort 2220 patients more than 18 years, who were performed CABG surgery in Massih Daneshvari Hospital, from January 2004 to March 2010 were recruited. Predicted mortality risk scores were calculated using logistic EuroSCORE and Acute Physiology and Chronic Health Evaluation II (APACHE II) and compared with observed mortality. Calibration was measured by the Hosmer-Lemeshow (HL) test and discrimination by using the receiver operating characteristic (ROC) curve area. Results: Of the 2220 patients, in hospital deaths occurred in 270 patients (mortality rate of 12.2%). The accuracy of mortality prediction in the logistic EuroSCORE and APACHE II model was 89.1%; in the local EuroSCORE (logistic) was 91.89%; and in the local EuroSCORE support vector machines (SVM) was 98.6%. The area under curve for ROC curve, was 0.724 (95% confidence interval [CI]: 0.57-0.88) for logistic EuroSCORE; 0.836 (95% CI: 0.731-0.942) for local EuroSCORE (logistic); 0.978 (95% CI: 0.937-1) for Local EuroSCORE (SVM); and 0.832 (95% CI: 0.723-0.941) for APACHE II model. The HL test showed good calibration for the local EuroSCORE (SVM), APACHE II model and local EuroSCORE (logistic) (P = 0.823, P = 0.748 and P = 0.06 respectively); but there was a significant difference between expected and observed mortality according to EuroSCORE model (P = 0.033). Conclusion: We detected logistic EuroSCORE risk model is not applicable on Iranian patients undergoing CABG surgery.