Validation of European Score for Cardiac Operative Risk Evaluation in cardiac surgical patients in Nepal

Abstract

Introduction: European System for Cardiac Operative Risk Evaluation (EuroSCORE) is the standard tool for risk stratification of patients undergoing cardiac surgery. Before using this tool in any population, its validation needs to be assessed. This study was carried out to check validation in cardiac surgical patients in Nepalese patients.

Method: This is a prospective observational analytical cohort study in 500 patients undergoing cardiac surgery for coronary artery bypass graft (CABG), valve replacement surgeries (mitral valve, aortic valve or double valve replacements) and valve and aorta replacement surgeries (Bentall procedure). The data were entered in the Microsoft excel software and were analyzed using Chi Square test from Statistical Package for Social Sciences (SPSS Version - 17) package. Calibration power and discriminative power were calculated.

Result: The model’s validation was assessed by its calibration and discriminative power. Calibration power was assessed using Hosmer- Lemeshow test (Chi-square test). It gave P value of 0.14 indicating that the model adequately fits the data and can predict mortality. Discriminative power was assessed by calculating area under the receiver operating characteristic (ROC) curve which was 0.71 indicating satisfactory discriminative power. In low and moderate risk groups, observed and predicted (additive and logistic) mortality were satisfactory. In high risk group, observed mortality was higher than predicted mortality. Logistic EuroSCORE value was nearer to observed value.

Conclusion: EuroSCORE can be applied in Nepalese cardiac surgical patients in low and moderate risk groups satisfactorily though additive EuroSCORE is better in prediction. In high risk groups, logistic and additive EuroSCORE under predicted outcome than the observed mortality. However logistic EuroSCORE was better in this group of patients. EuroSCORE needs to be refined to apply on high risk Nepalese cardiac surgical patients.