Mitral Annular Calcification: Natural History, Prognosis, and Clinical Outcomes

Mitral annular calcification (MAC) is a chronic and progressive degenerative process characterized by calcium and lipid deposition of the mitral valve annulus. We sought to describe the natural history of patients with MAC with and without mitral valve dysfunction (MVD).

We conducted an observational study of patients with an echocardiogram-based diagnosis of MAC from 2006-2023. Patients were matched by age and sex in a 1:1 ratio to patients without MAC. We collected baseline clinical, echocardiographic, and computed tomography data. The primary end point was all-cause mortality. We also report predictors of mortality in patients with MAC and MVD.

We included 15,372 patients in the analysis: 7686 with MAC (median age, 76 years [68-84], 58% women) and 7686 without MAC matched by age and sex. Patients with MAC had higher rates of comorbidities, cardiovascular risk factors, MVD, and multivalvular heart disease (aortic stenosis/regurgitation and tricuspid regurgitation) relative to patients without MAC (all P < .001). Two-year mortality was 14%, 26%, and 21% for patients with MAC and no MVD, MAC with ≥moderate MR, and MAC with ≥moderate MS, respectively (P < .001). Surgical or transcatheter mitral valve interventions in patients with MAC and significant MVD were infrequently performed (n = 136/788, 17.2%).

Ten percent of patients with MAC have clinically significant MVD, with mitral regurgitation being more common than mitral stenosis. The presence of MVD is associated with significantly increased mortality in patients with MAC.