Validation of the European system for cardiac operative risk evaluation (EuroSCORE) in Chinese heart valve surgery patients

Abstract

Background and aim of the study: The study aim was to assess the performance of the European System for Cardiac Operative Risk Evaluation (EuroSCORE) model in Chinese patients undergoing heart valve surgery.

Methods: Between January 2003 and December 2007, the data from a total of 1726 consecutive patients who underwent heart valve surgery at the authors' center were collected and scored according to the additive and logistic EuroSCORE models. The patients were allocated to three risk subgroups, and the entire cohort and each risk subgroup analyzed. Calibration of the EuroSCORE model was assessed by the Hosmer-Lemeshow (H-L) test. Discrimination was tested by calculating the area under the receiver operating characteristic (ROC) curve.

Results: Completed data from all 1726 patients were analyzed. There were significant differences in the prevalence of risk factors between the study sample and European cardiac surgery populations. The observed mortality was 4.46% overall, compared to 3.51% (additive) and 2.85% (logistic). The additive EuroSCORE model showed good calibration in predicting in-hospital mortality (H-L; p = 0.204), but the logistic EuroSCORE model underpredicted observed mortality (H-L; p = 0.038) in the entire cohort. Both, the additive and logistic EuroSCORE models showed good calibration in predicting in-hospital mortality in the medium- and high-risk subgroups, but overpredicted observed mortality in the low-risk subgroup. The discriminative power of both models for the entire cohort was poor (areas under the ROC curve of 0.644 and 0.647 for the additive and logistic models, respectively).

Conclusion: The additive and logistic EuroSCORE models gave an imprecise prediction for individual operative risk in heart valve surgery patients at the authors' center; thus, use of the EuroSCORE models for risk evaluation at this center may be unsuitable in the future. It will be necessary to re-examine the performance of the EuroSCORE model for predicting operative mortality in heart valve surgery on a multicenter database in China.