Relationship Between Mitral Annular Calcification and Coronary Artery Calcification in Asymptomatic Individuals

Objective: Despite the common atherosclerotic origins of mitral annular calcification (MAC) and coronary artery calcification (CAC), the relationship between MAC and CAC is not fully understood. We aimed to identify the factors associated with prevalent MAC and CAC, and also with their progression. Design and method: Using data from the KOrea Initiatives on Coronary Artery (KOICA) registry, 722 asymptomatic individuals who underwent health screening with serial cardiac computed tomography (CT) were selected for analysis. MAC and CAC were identified on CT, and the severity quantified using Agatston units (AU). The associations between the prevalence, severity, and the annualized progression rate of MAC and CAC were identified using multivariable regression models. Results: On initial CT, 47 (6.5%) participants had prevalent MAC and 334 (46.3%) had prevalent CAC. Increasing CAC severity was associated with a significantly higher probability of prevalent MAC (OR per 100 AU increase 1.06, 95% CI 1.05-1.07, p<0.001) even after correction for baseline characteristics. Similar results were true when CAC severity was assessed as a graded variable. Other factors associated with MAC were older age, female sex, higher body-mass index, diabetes, higher systolic blood pressure, and left atrial volume index. In those with prevalent MAC and CAC, the factors associated with a higher MAC progression rate were initial MAC severity (p<0.001), female sex (p=0.01), and higher serum phosphorus (p<0.001), while the factors associated with a higher CAC progression rate were initial CAC severity (p<0.001) and higher low-density lipoprotein cholesterol (p=0.02). Conclusions: We observed a close correlation between MAC and CAC, which is in accord with their common atherosclerotic origin. However, the differences in risk factors associated with the progression rate of MAC and CAC suggest the importance of site-specific mechanisms in the progression of calcification.