Abstract 18614: Comparison of the New EuroSCORE II with the Original EuroSCORE and the Society of Thoracic Surgeons Risk Score

Abstract

Background: The new EuroSCORE II was developed to improve the prediction risk model of the EuroSCORE I.. In the USA, the Society of Thoracic Surgeons (STS) risk score is more accepted despite being less user friendly and non-applicable to some of the cardiac surgeries. The purpose of this study was to compare the performance of the new EuroSCORE II with the logistic EuroSCORE I and STS mortality predicted risk score .

Methods: Prospectively collected data from all cardiac surgery patients at a single center with complete data for the three scores (N=9,966) was used. A subabnalysis for patients with cardiac surgeries not accommodated by the STS risk model was performed for comparison of the EuroSCORE II & I (N=4,738). Correlations were conducted between each score and ROC curves were calculated for operative mortality determining the discriminative ability score.

Results: Our center’s observed operative mortality was 2% -the mean predicted mortality for STS was 2.8%, 3.3% for EuroSCORE II and 7.7% for EuroSCORE I. The discriminative ability of the EuroSCORE II for operative mortality by the area under the curve (AUC) was 0.836, for EuroSCORE I (AUC=0.812) and for the STS score (AUC=0.833). The EuroSCORE II was highly correlated with the EuroSCORE I (r=0.83, p<0.001) and the STS score (r=0.78, p<0.001). The EuroSCORE II had a higher correlation with the STS score than the EuroSCORE I (r=0.70, p<0.001). In the subanalyses comparing the EuroSCORE II vs I, the scores were highly correlated (r=0.74, p<0.001). For operative mortality (observed=4%), the EuroSCORE II had better discriminative ability (expected=5.6%, AUC=0.749) compared to EuroSCORE I (expected=12.4%, AUC=0.687).

Conclusions: The new EuroScore II has better operative mortality discrimination compared to the original EuroSCORE, which greatly overestimated the predicted risk of operative mortality. The EuroSCORE II fared well with the STS risk score. Due to the inclusive nature of the EuroSCORE II for multiple procedures, it provides more flexibility than the STS score when dealing with patients undergoing very complex procedures. The EuroSCORE II should be considered when obtaining a risk score for complex cardiac surgical patients.