Should valve leaflet thickening be considered a characteristic lesion of infective endocarditis?

BACKGROUND: Valve leaflet thickening was recently incorporated into the 2023 version of the Duke criteria by the European Society of Cardiology (ESC) as a potential imaging marker of infective endocarditis (IE). The study aimed to assess the impact of valve leaflet thickening on the diagnosis of IE among patients investigated for suspected IE. METHODS: This retrospective study included adults with suspected IE at Lausanne University Hospital (2014-2025). IE was diagnosed by the 2023 Duke-ISCVID based on the clinical, pathological, and rejection criteria. Reclassification of IE status was assessed according to the 2023 Duke-ESC clinical criteria with and without inclusion of leaflet thickening. RESULTS: Among 3,747 episodes of suspected IE, valve leaflet thickening was identified in 288 (8%). IE was diagnosed in 193/288 (67%) episodes. Among the 193 IE episodes, 62 (32%) showed no additional intracardiac lesion typically associated with IE. When leaflet thickening was excluded from imaging criteria, 144 episodes (50%) still fulfilled a major imaging criterion according to the 2023 Duke-ESC clinical criteria. Incorporation of leaflet thickening into the 2023 Duke-ESC clinical criteria increased sensitivity from 59% (95% CI: 52-66%) to 79% (95% CI: 73-85%), while specificity decreased from 98% (95% CI: 93-100%) to 46% (95% CI: 36-57%). CONCLUSIONS: Valve leaflet thickening is a frequent but non-specific imaging finding that substantially reduces diagnostic specificity when incorporated into the 2023 Duke-ESC clinical criteria. Its use as a major imaging criterion risks overdiagnosis and overtreatment, underscoring the need for cautious interpretation within a multidisciplinary diagnostic framework.