Mitral annular calcification score by computed tomography in patients undergoing mitral valve surgery

Mitral annular calcification (MAC) increases the difficulty of mitral valve (MV) surgery and is associated with mortality. However, there is no standardized classification of MAC severity. A multi-parametric MAC score has been proposed using computed tomography. We evaluated the prognostic effect of MAC severity classification using the MAC score.

We included 331 patients with MAC who underwent MV surgery from 2011 through 2019. We calculated the MAC score based on five main components (range: 2-12): MAC Agatston calcium score, MAC angle, extension to left ventricular outflow tract, the involvement of trigones, and myocardial infiltration. According to the proposed MAC score, we classified the top tertile into the severe MAC group (scores: 9-12, n = 63) and the others into non-severe MAC group (scores: 2-8, n = 268). Propensity scores (PS) were estimated using seven clinical variables (age, sex, body mass index, hypertension, diabetes mellitus, heart failure, and chronic kidney disease), with severe MAC as the dependent variable. The median age was 74 years and 57.1% were female. During a median follow-up duration of 220 days, 47 patients (14.2%) died. After PS matching, there were 60 patients in each group. There were no significant differences in in-hospital mortality between the two groups, but patients with severe MAC had statistically significantly higher all-cause mortality compared to patients with non-severe MAC (25.0% vs. 8.3%, P = 0.026).

In patients undergoing MV surgery, systematic classification of MAC severity by MAC score helps predict prognosis.