Degenerative mitral regurgitation is the second most frequent valvular heart disease in Europe. In Western countries, the degenerative etiology is predominant, while in developing countries, rheumatic causes remainprevalent. According to the guidelines developed by the European Society of Cardiology (ESC) and theEuropean Association for Cardio-Thoracic Surgery (EACTS), surgery is indicated in patients with severe symptomatic primary mitral regurgitation and acceptable surgical risk, in asymptomatic patients with leftventricular dysfunction (left ventricular end-systolic diameter or LVESD > 40 mm, left ventricular ejectionfraction or LVEF ≤ 60%), and it should be considered in asymptomatic patients with preserved left ventricular function (LVESD < 40 mm and LVEF > 60%) who present with atrial fibrillation secondary to mitral regurgitation or pulmonary hypertension at rest. 

Degenerative mitral regurgitation is associated with heart failure, arrhythmias, and poor long-term outcomes. When surgically treated in a timely manner, normal life expectancy may be restored. Previous studies reportthat, despite its higher prevalence, women may be referred for surgery less frequently and at a more advanced stage of disease, potentially impacting surgical and prognostic outcomes. This study aims tocompare the clinical and echocardiographic differences between men and women to assess the need foradjustments in surgical indications, with the goal of improving postoperative recovery times and long-termoutcomes. 

The study was conducted at Massachusetts General Hospital, reviewing electronic medical records of allpatients undergoing mitral valve surgery from January 2013 to December 2021. The study included patientswith severe mitral regurgitation due to Carpentier type II mechanisms and excluded reoperations. Perioperative mortality and early postoperative complications (including mechanical circulatory supportrequirement, mechanical ventilation > 24 hours, postoperative stroke, and in-hospital death) were evaluated, along with long-term freedom from reoperation and death. 

A total of 963 patients with degenerative mitral regurgitation were included. At the time of surgical referral, women were older than men. Men had significantly higher rates of arterial hypertension, coronary arterydisease, and body mass index, whereas women had higher NT-proBNP levels, mitral annular calcification, and predicted mortality risk based on the STS-PROM (Society of Thoracic Surgeons – Predicted Risk ofMortality) score. Although absolute left ventricular dimensions were greater in men, these differencesreversed when indexed to body surface area. Beyond conventional echocardiographic measurements, thestudy employed additional techniques, such as atrial strain analysis, finding lower peak values in women forleft atrial strain parameters, which, along with other findings, suggest higher degrees of left ventricular overload and damage in women, associated with decreased survival. Women required mechanicalcirculatory support more frequently, all due to severe biventricular dysfunction after weaning fromcardiopulmonary bypass despite high inotropic support. They also required longer mechanical ventilation, spent more time in intensive care units, needed more transfusions, and had prolonged hospital stays. No differences were observed in other postoperative complications. 

Based on these findings, the authors concluded that women present for surgery at a more advanced stageof the disease and experience more perioperative complications, highlighting the potential benefit of earlierinterventions. 

COMMENTARY:

This study’s primary finding is the apparent clinical differences between men and women at the time ofdeciding on mitral valve surgery. These differences significantly influence the likelihood of perioperativecomplications and prognosis. But how should this be interpreted? 

Although absolute left ventricular dimensions were greater in men, these differences equalized or reversedwhen indexed to body surface area. It is likely that the LVESD > 40 mm threshold in asymptomatic patients, as outlined in clinical practice guidelines, is based on studies conducted predominantly in male populations. A large international study suggested considering LVESD/BSA > 21 mm/m² as a better decision-makingthreshold. 

Based on the analyses performed in this study, it may be beneficial to include indexed parameters and strain, which are relatively easy to obtain, in standard echocardiographic evaluations. This would providemore comprehensive information and could influence earlier intervention in women, improving short- and long-term outcomes. 

While this analysis focuses on body surface area and especially echocardiographic parameters, otherstudies suggest incorporating magnetic resonance imaging into preoperative assessments. MRI can evaluate left ventricular dimensions as well as structural abnormalities such as fibrosis, which are predictorsof advanced disease and certain complications. Including these findings in routine evaluations couldenhance the quality of evidence. 

Although short- and long-term mortality were comparable between men and women in this analysis, theobserved differences in perioperative complications seem significant. Even though this was a retrospective analysis of a relatively small, single-center cohort with the inherent limitations in evidence level, it is evidentthat the sex-based disparities in outcomes warrant further, larger studies designed to produce more validresults. Such studies would enable objective evaluation and focus on strategies to equalize perioperativeand prognostic outcomes. It is also clear that we must continuously review and promote updates in theguidelines that guide decision-making in our clinical practice. 

REFERENCE:

Van Kampen A, Butte S, Paneitz DC, Nagata Y, Langer NB, Borger MA, et al. Presentation and outcomes of women and men undergoing surgery for degenerative mitral regurgitation. Eur J Cardiothorac Surg. 2024 Sep 2;66(3):ezae312. doi: 10.1093/ejcts/ezae312. PMID: 39141430.