Prevalence and Natural History of Mitral Annulus Calcification and Related Valve Dysfunction

Objective: To evaluate the prevalence and natural history of mitral annulus calcification (MAC) and associated mitral valve dysfunction (MVD) in patients undergoing clinically indicated echocardiography. Methods: A retrospective review was conducted of all adults who underwent echocardiography in 2015. Mitral valve dysfunction was defined as mitral regurgitation or mitral stenosis (MS) of moderate or greater severity. All-cause mortality during 3.0 (0.4 to 4.2) years of follow-up was compared between groups stratified according to the presence of MAC or MVD. Results: Of 24,414 evaluated patients, 5502 (23%) had MAC. Patients with MAC were older (75±10 years vs 60±16 years; P<.001) and more frequently had MVD (MS: 6.6% vs 0.5% [P<.001]; mitral regurgitation without MS: 9.5% vs 6.1% [P<.001]). Associated with MS in patients with MAC were aortic valve dysfunction, female sex, chest irradiation, renal dysfunction, and coronary artery disease. Kaplan-Meier 1-year survival was 76% in MAC+/MVD+, 87% in MAC+/MVD−, 86% in MAC−/MVD+, and 92% in MAC−/MVD−. Adjusted for age, diabetes, renal dysfunction, cancer, chest irradiation, ejection fraction below 50%, aortic stenosis, tricuspid regurgitation, and pulmonary hypertension, MAC was associated with higher mortality during follow-up (adjusted hazard ratio, 1.40; 95% CI, 1.31 to 1.49; P<.001); MVD was associated with even higher mortality in patients with MAC (adjusted hazard ratio, 1.79; 95% CI, 1.58 to 2.01; P<.001). There was no significant interaction between MAC and MVD for mortality (P=.10). Conclusion: In a large cohort of adults undergoing echocardiography, the prevalence of MAC was 23%. Mitral valve dysfunction was more than twice as prevalent in patients with MAC. Adjusted mortality was increased in patients with MAC and worse with both MAC and MVD.