Abstract 15003: Risk Factors Associated With the Initiation and Progression of Mitral Annular Calcification: A Two-Step Process

Background: Mitral annular calcification (MAC) is hypothesized to be a representation of atherosclerosis and is associated with adverse outcomes. However, the pathophysiology and risk factors associated with MAC are not completely understood.

Methods: From the KOrea Initiatives on Coronary Artery calcification registry, 738 asymptomatic individuals who underwent health screening with echocardiography and serial cardiac computed tomography (CT) scans were included for analysis. MAC was identified on CT and measured using Agatston units (AU). Risk factors associated with the initiation of MAC were identified with multivariable logistic regression, and risk factors associated with the progression of MAC were determined using multivariable linear regression on the annualized progression of the MAC AU.

Results: The initial prevalence of MAC was 7.0%, and the median rate of progression was 3.4 AU/year (IQR 0.2-14.7 AU/year) during a median interscan duration of 36.4 months. In addition, 4.3% of the participants developed new MAC between the first and last examinations. The factors associated with the initiation of MAC were age (p<0.001), body mass index (p=0.046), history of smoking (p=0.048), HbA1c (p=0.011), and left atrial volume index (p=0.034). Meanwhile, the factors associated with MAC progression were initial MAC Agatston score (p<0.001), male sex (p=0.005), and calcium-phosphorus product (p=0.002).

Conclusion: Traditional cardiovascular risk factors and increased hemodynamic stress seem to be more important in the initiation of MAC, while initial MAC severity and calcium-phosphate metabolism seem to be a major determinant in the later phase of MAC progression.