Background: This research was aimed at validating a new risk model for in-hospital mortality in Chinese patients undergoing coronary artery bypass graft (CABG) surgery. This model (NYS), which was developed for isolated CABG surgery from data of New York's cardiac surgery reporting system in 2002, was proved effective, but its validation in Chinese patients has yet to be carried out.
Methods: The original model was recalibrated, and the fitness of the recalibrated model was tested in the Chinese Coronary Artery Bypass Graft Registry. From January 2004 to December 2005, 9248 patients undergoing CABG were enrolled in the Chinese CABG Registry, and 8120 patients who underwent isolated CABG were selected for the current study.
Results: The C statistic value for the original model was 0.74 (95% confidence interval [CI], 0.70-0.78), and the chi2 statistic was >26.13 (P < .001), indicating a necessity for recalibration. The fit of the recalibrated model was satisfactory (C statistic, 0.74 [95% CI, 0.70-0.78]; chi2 = 5.98; P = .65). Furthermore, translation of risk profiles into NYS scores revealed strong correlations between risk-score levels and different end points, including in-hospital mortality, major adverse cardiac events, and length of intensive care unit stay. Independent predictors were identified in the Chinese CABG Registry. Many predictors for the Chinese CABG Registry were the same as those in the NYS model.
Conclusions: The original NYS system overestimates in-hospital mortalities in Chinese patients undergoing CABG, whereas the recalibrated model corrects such overestimations. This model can be a useful risk-predictive tool for Chinese patients undergoing isolated CABG.