Mind the Gap: Inadequate Performance of Embolic Risk Scores in Infective Endocarditis

Embolic events (EEs) are frequent and clinically important complications of infective endocarditis (IE). Three scores have been developed to predict EEs: the Embolic Risk French Calculator (for EEs occurring after treatment initiation), and the Italian Endocarditis Study and University of Campania "L. Vanvitelli" Napoli Score (for EEs occurring before or after antimicrobial initiation). This study aimed to externally validate and compare the predictive performance of these scores.

This is a multicenter retrospective study including adult patients diagnosed with IE between 2014 and 2024 at Lausanne University Hospital and University Hospital Zurich. Embolic events and IE were defined according to the 2023 International Society of Cardiovascular Infectious Diseases (ISCVID) Duke criteria. Scores were applied according to their respective populations, and performance was evaluated using sensitivity, specificity, and accuracy.

Among 1331 IE episodes, 674 (51%) experienced EEs, with 474 (36%) before and 348 (26%) after antimicrobial initiation. The Embolic Risk French Calculator, applied to 1201 valve-related IE episodes, identified 358 (30%) as high risk. Accuracy for predicting postantibiotic EEs was 66% (95% CI 64%-69%). The Italian Endocarditis Study score, applied to 1073 episodes with left-side IE, classified 563 (53%) as intermediate/high risk, with an overall accuracy of 60% (56%-62%). The University of Campania score, applied to 701 valve-related IE episodes, identified 341 (49%) as intermediate/high risk, with an accuracy of 63% (60%-67%).

All 3 scores demonstrated limited predictive accuracy and frequently misclassified patients. More robust tools are needed to guide embolic risk stratification in clinical practice.