Abstract Body (Do not enter title and authors here): Background
While sex differences have been observed in various valvular heart diseases, data on rheumatic mitral stenosis, the most common form globally, remain limited.

Objective
We sought to determine sex differences in rheumatic mitral stenosis (MS).

Methods
From the 3,140 patients in the Multicenter MitrAl STEnosis with Rheumatic etiology (MASTER) registry in South Korea between January 2001 and December 2020, 2,631 patients who were diagnosed with moderate or severe rheumatic MS were included, after excluding those who had undergone prior mitral valve (MV) intervention. Patients were categorized by sex, and we compared demographics, echocardiographic data, and clinical outcomes, including all-cause death, heart failure hospitalization, MV intervention, and ischemic stroke.

Results
Among the total population (n=2,631), 74.1% (n=1,950) were women. Compared to men, women were older (60.4 ± 13.0 vs. 58.5 ± 12.2, p<0.001), had a lower prevalence of atrial fibrillation (AF) (50.6 vs. 63.1%, p<0.001), a lower mean diastolic pressure gradient (6.8 ± 3.7 vs. 7.3 ± 4.1 mmHg, p=0.009), and a smaller left ventricular mass index (96.5 ± 29.0 vs. 107.1 ± 34.0 ml/m²). All-cause mortality, heart failure hospitalization, and MV intervention rates were similar between the sexes. However, women had a significantly higher incidence of ischemic stroke compared to men (log-rank p=0.007, Figure 1). This finding remained consistent in propensity-matched analysis (p=0.007, Figure 2) after adjusting for clinical and echocardiographic variables, including AF.

Conclusion
Women with moderate to severe MS had a higher risk of ischemic stroke compared with men. These findings might suggest the need for sex-specific anticoagulation strategies in the management of rheumatic MS.