Impact of Sex on Severity Assessment and Cardiac Remodeling in Primary Mitral Regurgitation

Background Women with severe primary mitral regurgitation (MR) have lower surgery rates than men and could suffer from delayed referral for mitral valve (MV) intervention, exposing them to an increased risk of postoperative adverse outcomes. Objectives The purpose of this study was to assess the sex-based differences in patients with primary MR. Methods The study sample consisted of 420 patients (median age: 62 years, 26% women) with primary MR due to valve prolapse referred for preoperative assessment who underwent transthoracic echocardiography (TTE) and cardiac magnetic resonance (CMR) imaging. Multiple endpoints (abnormally increased left ventricular size, NYHA functional class III/IV, severe left atrial [LA] dilatation, pulmonary hypertension) were studied using areas under the curves and logistic regression models. Results Women were older than men, had higher NYHA functional class and larger indexed LA volumes (all P ≤ 0.031), despite displaying lower MR effective regurgitant orifice area, regurgitant volumes (RegVol), and ventricular volumes than men (all P ≤ 0.002). The optimal cut-off values of RegVol associated with abnormally increased left ventricular size according to reference normal values were lower in women (TTE: 67 ml, CMR: 50 ml) than in men (TTE: 77 ml, CMR: 65 ml). MR regurgitant fraction, but not RegVol, was associated in women and men with NYHA functional class III/IV, severe LA dilatation, and pulmonary hypertension (all areas under the curves, P ≤ 0.024). Conclusions Despite having hallmarks of more advanced valvular heart disease, women with significant primary MR demonstrate lower mitral RegVol and ventricular volumes than men. In contrast, the systematic calculation of MR regurgitant fraction could standardize MR quantification irrespective of sex.