Sex Differences in Clinical Presentation and Outcome of Degenerative Mitral Regurgitation Quantified: The MIDA-Q Registry

BACKGROUND: Degenerative mitral regurgitation (DMR) due to valve prolapse predominates in men, but sex-specific differences are poorly understood due to a lack of quantitative and sex-stratified studies. METHODS: The international MIDA-Q (Mitral Regurgitation International Database-Quantitative) registry enrolled 3274 men and 2331 women with greater than or equal to mild DMR prospectively quantified, comprehensively characterized, and long-term follow-up. RESULTS: Women were more symptomatic despite lower effective regurgitant orifice (ERO, 27±18 versus 38±22 mm 2 , standardized mean difference 0.54; P <0.0001) and regurgitant volume (46±26 versus 61±31 mL/beat, standardized mean difference 0.52; P <0.0001), even for similar mitral lesions. With increasing ERO, women showed lower regurgitant volume, higher heart rate, lower blood pressure, but left ventricular size response in women was smaller in absolute measures while larger when body surface area normalized, with higher ejection fraction and cardiac index (all P <0.0001). Incidence of mitral valve surgery was similar in symptomatic women and men, but lower in asymptomatic women versus men (adjusted hazard ratio, 0.80 [0.69–0.94]; P =0.008) for similar ERO, linked to smaller left ventricular diastolic absolute diameter ( P <0.0001). Excess mortality under medical management (of severe versus mild ERO) was similar in women (adjusted hazard ratio, 1.67 [1.24–2.24]; P =0.0007) and men (adjusted hazard ratio, 1.63 [1.27–2.09]; P <0.0001) and versus expected survival (2.12 [1.51–2.98] in women and 2.27 [1.75–2.94] in men). However, moderate ERO (20–39 mm 2 ) was associated with significant excess mortality in women (1.47 [1.19–1.77] versus mild). In men, the corresponding hazard ratio did not reach statistical significance. Postoperative survival was similar in men and women. CONCLUSIONS: Women with DMR present with lower ERO and regurgitant volume than men and with considerable adaptive differences to increasing DMR severity versus men. Asymptomatic women are less referred to surgery than men of similar DMR severity, linked to smaller absolute left ventricular size. Severe DMR by similar quantitative thresholds causes similar excess mortality in men and women; moderate quantitative DMR shows a trend for higher excess mortality versus expected in women than men, requiring further confirmation. These data emphasize the importance of quantitative DMR and left ventricular remodeling assessment in men and women for appropriate clinical management.