Cardiac Surgery Resident University of Ottawa Heart Institute Ottawa, Ontario, Canada
Background: The pathophysiology and clinical presentation of ischemic mitral regurgitation (IMR) differs between sexes. Furthermore, there is conflicting data on the prognosis of mitral valve surgery for IMR in females compared to males. The goal of this cohort study is to assess sex-based all-cause mortality following surgery for chronic IMR.
METHODS AND RESULTS: All consecutive patients who underwent mitral valve repair or replacement for chronic IMR between January 1, 2000 and December 31, 2022 at the University of Ottawa Heart Institute or the Quebec Heart and Lung Institute were included. Inverse probability of treatment weighting (IPTW) using stabilized weights was performed to account for differences in baseline characteristics between sexes. The two co-primary outcomes were sex-based 30-day and long-term mortality and were assessed with logistic and Cox regression models, respectively.
A total of 1086 patients (330 [30.4%] females) were included in the study cohort. Median follow-up was 6.2 ± 5.3 years. Age, baseline left ventricular ejection function, NYHA class and rates of hypertension and congestive heart failure were higher in females while smoking and atrial fibrillation were more common in males (Table 1). IPTW resulted in good balance of baseline characteristics between sexes (standardized mean difference [SMD] < 0.10). Mitral valve replacement was performed in 658 patients (60.6%), of which 256 (38.9%) were mechanical prostheses. There were no sex differences in rates of mechanical mitral prostheses (SMD: 0.07). Concomitant surgical revascularization was performed in 947 patients (87.2%; 279 [84.5%] females and 668 [88.4%] males). Median cardiopulmonary bypass and cross-clamp times were 133 (interquartile range [IQR]: 109-159) and 100 (IQR: 81-122) minutes, respectively. Thirty-six (10.9%) females and 42 (5.6%) males died at 30 days (Weighted odds ratio [95% confidence interval (CI)]: 1.77 [1.01-3.10]). Other procedural predictors for 30-day mortality included longer cardiopulmonary bypass times and emergency surgery. Median survival was 9.7 and 10.7 years for females and males, respectively (Log-rank p-value = 0.031; Figure 1). After adjustment for type of mitral valve surgery and concomitant tricuspid valve repair, long-term mortality was similar between sexes (Hazard ratio [95% CI]: 1.06 [0.87-1.30], p-value = 0.545). However, mitral valve replacement was an independent predictor for long-term mortality (Hazard ratio [95% CI]: 1.45 [1.20-1.75], p-value < 0.001).
Conclusion: In this cohort, females with IMR presented at an older age and with a higher NYHA class than males. After IPTW and multivariate adjustment, all-cause 30-day mortality remained higher in females, but long-term mortality was similar between sexes.
