Mitral annulus calcification and the risk of infective endocarditis: insights from DANCAVAS screening trials

AIMS: Risk stratification in infective endocarditis (IE) does not incorporate structural substrates involved in early disease initiation. The aim of this study was to examine the association between mitral annulus calcification (MAC) burden and the risk of IE. METHODS AND RESULTS: This substudy utilized the population-based DANCAVAS cohort undergoing non-contrast computed tomography (CT) with MAC quantification with follow-up until 19 August 2025. The primary outcome was incidence rates and 10-year risk of IE across three exploratory categorical groups: No MAC (0 arbitrary units (AU)), MAC 1-299 AU, and MAC ≥300 AU. A total of 14 793 participants were included with mean (SD) age, 66.9 (3.8) years, and 14 053 males (95.0%). Median MAC was 13 AU (IQR3.3-56.2) in the MAC 1-299 group and 680 AU (IQR447-1271) in the MAC ≥300 group. IE incidence rate per 10 000 person-years was 1.92 for no MAC, 2.48 for MAC 1-299, and 21.3 for MAC ≥300 (P < 0.001). The 10-year cumulative risk was, 0.20%(95%CI 0.12-0.33) for no MAC, 0.22% (95%CI 0.10-0.49) for MAC 1-299, and 1.85% (95%CI 0.93-3.69) for MAC ≥300 (P < 0.001). Each 100 AU increase in MAC was associated with a 3% increase in the risk of IE (HR 1.03, 95%CI 1.01-1.05, P = 0.011). MAC ≥300 AU remained associated with IE after adjustment for established risk factors (HR 7.05, 95%CI 2.85 to 17.4, P < 0.001). CONCLUSION: Greater MAC burden was associated with a higher risk of IE. In exploratory categorical analyses, MAC ≥300 AU was associated with the highest observed risk, although these findings should be interpreted with caution given the limited number of events.