Prediction of 30-day mortality after surgery for infective endocarditis using risk scores: Insights from a European multicenter comparative validation study

Background: It remains unclear today whether risk scores created specifically to predict early mortality after cardiac operations for infective endocarditis (IE) outperform or not the European System for Cardiac Operative Risk Evaluation II (EuroSCORE II). Methods: Perioperative data and outcomes from a European multicenter series of patients undergoing surgery for definite IE were retrospectively reviewed. Only the cases with known pathogen and without missing values for all considered variables were retained for analyses. A comparative validation of EuroSCORE II and five specific risk scores for early mortality after surgery for IE - (1) STS-IE (Society of Thoracic Surgeons for IE); (2) PALSUSE (Prosthetic valve, Age ≥70, Large intra-cardiac destruction, Staphylococcus spp, Urgent surgery, Sex (female), EuroSCORE ≥10); (3) ANCLA (Anemia, New York Heart Association class IV, Critical state, Large intra-cardiac destruction, surgery on thoracic Aorta); (4) AEPEI II (Association pour l'Étude et la Prévention de l'Endocardite Infectieuse II); (5) APORTEI (Análisis de los factores PROnósticos en el Tratamiento quirúrgico de la Endocarditis Infecciosa) - was carried out using calibration plot and receiver-operating characteristic curve analysis. Areas under the curve (AUCs) were compared 1:1 according to the Hanley-McNeil's method. The agreement between APORTEI score and EuroSCORE II of the 30-day mortality prediction after surgery was also appraised. Results: A total of 1,012 patients from five European university-affiliated centers underwent 1,036 cardiac operations, with a 30-day mortality after surgery of 9.7%. All IE-specific risk scores considered achieved better results than EuroSCORE II in terms of calibration; AEPEI II and APORTEI score showed the best performances. Despite poor calibration, EuroSCORE II overcame in discrimination every specific risk score (AUC, 0.751 vs. 0.693 or less, p=0.01 or less). For a higher/lesser than 20% expected mortality, the agreement of prediction between APORTEI score and EuroSCORE II was 86%. Conclusion: EuroSCORE II discrimination for 30-day mortality after surgery for IE was higher than five established IE-specific risk scores. AEPEI II and APORTEI score showed the best results in terms of calibration.