Objectives: To compare and validate the new European System for Cardiac Operative Risk Evaluation (EuroSCORE) II with EuroSCORE at our institution.
Methods: The logistic EuroSCORE and EuroSCORE II were calculated on the entire patient cohort undergoing major cardiac surgery at our centre between January 2005 and December 2010. The goodness of fit was compared by means of the Hosmer-Lemeshow (HL) chi-squared test and the area under the curve (AUC) of the receiver operating characteristic curves of both scales applied to the same sample of patients. These analyses were repeated and stratified by the type of surgery.
Results: Mortality of 5.66% was observed, with estimated mortalities according to logistic EuroSCORE and EuroSCORE II of 9 and 4.46%, respectively. The AUC for EuroSCORE (0.82, 95% confidence interval [CI] 0.79-0.85) was lower than that for EuroSCORE II (0.85, 95% CI 0.83-0.87) without the differences being statistically significant (P = 0.056). Both scales showed a good discriminative capacity for all the pathologies subgroups. The two scales showed poor calibration in the sample: EuroSCORE (χ(2) = 39.3, P(HL) < 0.001) and EuroSCORE II (χ(2) = 86.69, P(HL) < 0.001). The calibration of EuroSCORE was poor in the groups of patients undergoing coronary (P(HL) = 0.01), valve (P(HL) = 0.01) and combined coronary valve surgery (P(HL) = 0.012); and that of EuroSCORE II in the group of coronary (P(HL) = 0.001) and valve surgery (P(HL) < 0.001) patients.
Conclusions: EuroSCORE II demonstrated good discriminative capacity and poor calibration in the patients undergoing major cardiac surgery at our centre.