Data-driven mortality risk prediction of severe degenerative mitral regurgitation patients undergoing mitral valve surgery

Sex-Specific Association of Left Ventricular Function With Mortality in Severe Mitral Regurgitation

Importance

The association between left ventricular (LV) systolic dysfunction and adverse outcomes in patients with severe degenerative mitral regurgitation (MR) may vary by sex.

Objective

To investigate the sex-specific association of LV systolic function with mortality in patients with severe degenerative MR.

Design, Setting, and Participants

This retrospective cohort study included consecutive patients who underwent surgery for severe degenerative MR at 2 tertiary hospitals in South Korea from 2006 to 2020. Preoperative LV ejection fraction (LVEF) and LV global longitudinal strain (LV-GLS) were measured, with absolute LV-GLS values reported. Patients were stratified by LVEF (≤55%, >55% to ≤60%, and >60%) and LV-GLS (<19.9%, ≥19.9% to <23.4%, and ≥23.4%) tertiles. Mortality status was verified through December 2023, with a median (IQR) follow-up duration of 8.2 (5.3-12.2) years. Data analysis was conducted in March 2024.

Exposures

Surgical MV repair or replacement.

Main Outcomes and Measures

The primary outcome was all-cause mortality after MV surgery. Restricted cubic spline (RCS) curves visualized the association between LVEF, LV-GLS, and mortality for each sex.

Results

Among 1686 patients, 1088 (64.5%) were men and 598 (35.5%) were women. Women were older than men (median [IQR] age, 62 [51-70] vs 54 [45-63] years) and had higher LVEF and LV-GLS than men did. During the follow-up, 220 (13.0%) deaths occurred (117 men [10.8%]; 103 women [17.2%]). In Kaplan-Meier curves, mortality in men increased in the lowest LVEF (≤55%) and LV-GLS (<19.9%) groups, whereas women exhibited an earlier increase in mortality at higher LVEF (55%-60%) and LV-GLS (19.9%-23.4%) levels. Multivariable Cox analyses showed a higher mortality risk associated with LVEF less than or equal to 55% (adjusted hazard ratio [HR], 3.48; 95% CI, 1.84-6.58; P < .001) and 55% to 60% (adjusted HR, 2.21; 95% CI, 1.36-3.58; P = .001) compared with LVEF greater than 60% in women, but not in men (P for interaction by sex = .02). RCS curves showed an earlier increase in mortality risk at higher LVEF and LV-GLS levels in women. Similar trends were observed in asymptomatic patients.

Conclusions and Relevance

In this cohort study of patients with severe degenerative MR, women had an earlier increase in mortality risk associated with LV systolic dysfunction, suggesting the need to consider sex-specific criteria for early surgery in asymptomatic patients.

Long-term outcome of isolated mitral valve repair versus replacement for degenerative mitral regurgitation in propensity-matched patients

Objective

This study was performed to investigate the long-term outcomes in patients with degenerative mitral regurgitation (MR) undergoing mitral valve repair (MVr) versus mitral valve replacement (MVR) without concomitant surgeries.

Methods

The study cohort comprised 1493 patients with degenerative MR who were treated with isolated mitral valve surgery between January 2000 and December 2017 in a large multicenter (5 hospitals) registry of the Province of British Columbia, Canada, including 991 with repair and 502 with replacement. A propensity-matched comparison and risk-adjusted model were used to analyze the outcomes.

Results

After propensity matching (415 matched pairs), the 30-day mortalities were 2.4% and 3.6% in the MVr and MVR groups respectively (odds ratio [OR], 1.500; 95% confidence interval [CI], 0.674-3.339; P = .32). The MVR group had significantly greater rates of prolonged inotrope usage >24 hours (P = .024), prolonged ventilation (P = .039), and blood transfusion (P = .023). The respective 1-, 5-, 10-, and 15-year survival rates were 95.7%, 88.8%, 71.4%, and 53.3% in the MVr group, and 93.0%, 81.6%, 61.3%, and 46.0% in the MVR group (hazard ratio [HR], 1.355; 95% CI, 1.105-1.661; P = .004). A multivariable analysis revealed that MVR was an independent risk factor for 30-day mortality (OR, 2.270; 95% CI, 1.089-4.732; P = .029) and long-term mortality (HR, 1.417; 95% CI, 1.161-1.729; P < .001). The HR of MVR over MVr remained consistently greater than 1.0 across all ages.

Conclusions

MVr is associated with lower postoperative morbidity and better long-term survival compared with MVR in patients undergoing isolated mitral valve surgery for degenerative MR. The benefit of MVr appears age-independent.