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.