Is mitral valve disease treated differently in men and women?

Abstract

This study was performed to determine if there is a sex-based bias in referral practices, complexity of disease, surgical treatment, or outcomes in patients undergoing mitral valve surgery at our institution. Data were collected from the Cardiovascular Research Database of the Clinical Trial Unit of the Bluhm Cardiovascular Institute at Northwestern Memorial Hospital and they were defined according to the Society of Thoracic Surgeons National Database ( www.sts.org ). All patients who had mitral valve replacement, mitral valve repair with annuloplasty ring placement, and mitral valve annuloplasty alone were evaluated, including patients who underwent concomitant tricuspid valve surgery, atrial fibrillation ablation, patent foramen ovale closure, and coronary artery bypass grafting. An unmatched comparison was made between the 836 men and 600 women in the entire cohort (N = 1436) and propensity score-matching was performed in 423 pairs of men and women. Additional propensity score-matching for 219 pairs of men and women with Type II mitral valve functional class and no coronary artery disease and for 68 pairs of men and women with Type 1 or Type IIIb mitral valve functional class. Propensity score matching was used to compare sex differences involving a greedy algorithm with a caliper of size 0.1 logit propensity score standard deviation units. Between 1 April 2004 and 30 June 2017, 1436 patients (41.8% women, mean age 61.1 ± 12.6 years (men), 62.9 ± 13.3 years (women)) underwent mitral valve surgery. The unmatched comparison for the entire cohort showed that, on average, at the time of surgery, women had higher Society of Thoracic Surgery risk scores, were older and had more heart failure, coronary artery disease, and mitral stenosis than men. Women received proportionately fewer mitral repairs and more atrial fibrillation ablation, and tricuspid valve surgery. Women had longer intensive care unit and hospital stays, required more dialysis, and suffered more transient ischemic attacks and cardiac arrests postoperatively, and 30-day mortality rate was higher for women. However, propensity score-matching of 846 of the patients (423 men; 423 women) indicated that both the surgical approaches and surgical outcomes were comparable for men and women who had similar levels of disease and co-morbidities. Additional propensity score-matching of only those patients with degenerative mitral regurgitation (DMR) (219 men; 219 women) and those with Type 1 or Type III mitral valve disease showed no differences in the surgical procedures performed or in 30-day mortality rates. Women appear to be referred for mitral valve surgery later in the course of their disease, which could possibly be on the basis of sex bias, but they may also have a more aggressive form of mitral valve disease than men. Regardless of the reasons for the later referral of women for mitral valve surgery, the clinical outcomes are dependent upon the severity of the mitral disease and associated co-morbidities at the time of surgery, not on the basis of sex bias.