External validation of EuroSCORE I and II in patients with infective endocarditis: results from a nationwide prospective registry

OBJECTIVES: The primary objective was to externally validate EuroSCORE I and II in surgically treated endocarditis patients. The secondary objective was to assess the predictive performance of both models across sex, redo surgery, age, and urgency. METHODS: Data were retrieved from the Netherlands Heart Registration. All patients with infective endocarditis who underwent cardiac surgery between 2013 and 2021 were included. Predictive performance was assessed by discrimination (area under the curve), calibration (calibration-in-the-large and calibration plots), and a decision curve analysis. RESULTS: Two thousand five hundred and sixty-nine cases were included. Overall postoperative 30-day mortality was 10.2%. The area under the curve was 0.73 for EuroSCORE I and 0.72 for EuroSCORE II. Both models overpredict postoperative 30-day mortality, with observed-to-expected ratios of 0.37 and 0.69. EuroSCORE I overpredicts mortality across the full range, whereas EuroSCORE II overpredicts mortality only above a 20% predicted probability. We observed no significant differences in predictive performance across sex, redo surgery, or age. Discriminative capacity of EuroSCORE II was poor in emergency surgeries. CONCLUSIONS: Both EuroSCORE models demonstrate acceptable discriminative capacity in IE patients. EuroSCORE I consistently overestimates mortality and should not be utilized in endocarditis patients. EuroSCORE II can be used in IE patients up to a predicted probability of approximately 20%, regardless of sex, redo surgery, or age. Beyond this point, the predicted mortality risk should be halved to approach the true mortality risk. EuroSCORE II should not be used for risk prediction in emergency endocarditis surgeries and patients should not be withheld from indicated surgical treatment solely based on high EuroSCOREs.