Sex Differences in Left Ventricular Size and Function before and after Mitral Valve Repair

Among healthy subjects, women have smaller cardiac size than men even after indexing for body surface area (BSA), as well as higher left ventricular ejection fraction (LVEF) and left ventricular (LV) global longitudinal strain (GLS). Despite this, little is known about sex differences in LV remodeling in patients with mitral valve prolapse (MVP) undergoing mitral valve repair (MVr). The aim of this study was to assess pre- and post-MVr sex differences in LV size and function in patients with MVP.

Patients with MVP who underwent surgery between 2007 and 2024 at two heart valve centers were included. Those with previous cardiac surgery, coronary artery disease, other concomitant procedures than tricuspid valve repair, nonsinus rhythm at baseline, and with significant postsurgical mitral regurgitation (grade ≥ 2) were excluded. LV size was evaluated before and after surgery using both end-systolic diameter (ESD) and end-systolic volume (ESV), while LV function was assessed using LVEF and GLS. Thresholds for normal sex-specific LV size and function were based on current recommendations. The primary outcome was postoperative LV damage, defined as the presence of increased LV ESV index, impaired LVEF, or impaired LV GLS. The ability of preoperative measures of LV size to discriminate outcomes was assessed using receiver operating characteristic curve analyses.

A total of 190 patients (37% women; mean age, 58 ± 12 years) were assessed 4 months (interquartile range, 1-6 months) before and 14 (interquartile range, 11-22 months) after surgery. Although men had significantly larger preoperative LV ESD (37 ± 5 vs 34 ± 5 mm), LV ESV (74 ± 20 vs 52 ± 13 mL), and LV ESV/BSA (36 ± 9 vs 30 ± 7 mL/m²) than women, LV ESD/BSA was higher in women (19 ± 3 vs 18 ± 2 mm/m²; P < .010 for all). Postoperatively, only men exhibited significantly lower LV ESV compared with the preoperative values, regardless of BSA indexing: LV ESV 62 ± 16 mL and LV ESV/BSA 31 ± 7 mL/m² in men (P < .001 for both) but LV ESV 50 ± 14 mL (P = .265) and LV ESV/BSA 29 ± 8 mL/m² (P = .216) in women. In multivariable logistic regression analysis, women were 6.3 (95% CI, 2.6-14.9; P < .001) times more likely than men to have a dilated left ventricle after MVr after adjusting for baseline characteristics (P < .001). LVEF was similar between sexes both before and after surgery. LV GLS was higher in women than in men before surgery (22.8 ± 2.6% vs 22.1 ± 2.2%, P = .038) but comparable after surgery (17.1 ± 2.6% vs 17.2 ± 2.2%, P = .715). Adjusting for age as well as preoperative LV GLS, LV size, and left atrial reservoir strain, women were 3.3 (95% CI, 1.5-7.3; P = .003) times more likely than men to have impaired LV GLS postoperatively (P < .001). The optimal cutoff of LV ESD/BSA to predict postoperative LV damage was 19 mm/m² in men and 16 mm/m² in women, with an area under the curve of 0.68.

In patients with MVP undergoing MVr, women have higher BSA-adjusted LV size by ESD, whereas ESV remains larger in men. Only men demonstrate a significant reduction in LV ESV after MVr, whereas women are more prone to postoperative LV dilatation and dysfunction. The present findings suggest that women are undergoing surgery at a later stage of disease and support the need for sex-specific assessment of preoperative LV size when referring patients to mitral valve surgery.