RISK PREDICTION IN CORONARY-ARTERY SURGERY - A COMPARISON OF 4 RISK SCORES

Objective: To determine which of four proposed risk scores best predic ts immediate outcome of cardiac surgery. Design: Observational cohort study. Setting: Sir Charles Gairdner Hospital (a university teaching h ospital), Perth, Western Australia, 18 March 1993 to 5 March 1996. Sub jects: 927 consecutive patients undergoing surgery for coronary artery disease. Outcome measures: Patient risk scores (by methods of Parsonn et et al., Higgins et al., Tremblay et al. and Tu et al.); in-hospital mortality; postoperative hospital stay > 14 days; receiver operating characteristic (ROC) curves comparing sensitivity and specificity in p redicting adverse outcomes for each risk score. Results: In-hospital m ortality rate was 3.5% and mean postoperative hospital stay was 10.7 d ays. The four scores had similar predictive abilities, with mean areas under the ROC curves (95% confidence intervals) for mortality and pos toperative stay > 14 days, respectively: 0.70 (0.62-0.78) and 0.70 (0. 65-0.75) for the Parsonnet score; 0.68 (0.59-0.77) and 0.70 (0.64-0.75 ) for the Higgins score; 0.68 (0.59-0.77) and 0.67 (0.62-0.73) for the Tremblay score; and 0.68 (0.60-0.76) and 0.69 (0.64-0.75) for the Tu score. Conclusion: Any of the scores may be used to estimate periopera tive risk and to compare outcome between coronary surgery units, but n one has sufficient specificity and sensitivity to identify specific in dividuals who will experience an adverse outcome. Further development of risk assessment is needed before adverse outcome can be accurately predicted in cardiac surgical patients.