Characteristics and Implications of Left Atrial Calcium on Cardiac Computed Tomography in Patients With Earlier Mitral Valve Operation

Abstract

Left atrial calcium (LAC) is often observed in patients who have undergone mitral valve (MV) surgery, but little is known about its characteristics and clinical implications. Therefore, we sought to investigate the structural and hemodynamic significance of LAC and its association with clinical outcomes. We investigated 327 patients with repaired or prosthetic MV who underwent cardiac CT from 2010 to 2017. The degree of LAC was analyzed and classified into three groups: group 1 (no LAC), group 2 (mild-to-moderate LAC), and group 3 (severe LAC). Clinical and echocardiographic characteristics and clinical outcomes were compared in three groups. LAC was seen in 79 (24.2%) patients. Groups 2 and 3 showed more prevalent atrial fibrillation, a rheumatic etiology, a higher number of previous surgeries, a larger LA volume index, and higher pulmonary artery systolic pressure than group 1. Paravalvular leakage of the MV increased progressively according to severity of LAC (15.4% in group 1, 39.3% in group 2, and 66.7% in group 3, p <0.001). Event-free survival rate for major adverse cardiovascular adverse events (log rank p = 0.033) and all-cause mortality (log rank p <0.001) were significantly different according to LAC group. In Cox regression analyses, presence of severe LAC was an independent predictor of all-cause mortality (hazard ratio: 4.44, 95% confidence interval: 1.71 to 11.58, p = 0.002). LAC on cardiac CT is not uncommon and reflects more advanced LA remodeling and a stiff LA. The presence and severity of LAC are associated with a worse clinical outcome after MV surgery.