Sex differences in outcomes after rheumatic and degenerative mitral surgery: a long-term follow-up analysis on 3012 patients

OBJECTIVES: This study aimed to assess the long-term outcomes of mitral valve (MV) disease depending on sex and its differences within the MV aetiology in patients undergoing MV surgery. METHODS: We reviewed 3012 patients undergoing isolated MV surgery with or without tricuspid valve (TV) surgery/ablation between January 2000 and December 2022. The primary end-points were all-cause mortality and a composite valve-related adverse events including heart failure, stroke, reoperation and infective endocarditis. Multivariate analysis with interaction terms identified independent risk factors, with median follow-up of 8.3 years (total 30 180.6 patient-years). RESULTS: Among the 3012 patients (54.8 ± 12.7 years), 1671 were females (55.5%). Rheumatic and degenerative MV diseases comprised 54.1% and 45.9%, respectively, with higher rates of rheumatic disease in females (69.7% vs 34.7%). Compared to males, females were older with higher prevalence of atrial fibrillation, TV insufficiency and advanced heart failure symptoms, consequently undergoing more MV replacements and concomitant procedures. Females showed higher rates of composite adverse outcomes (hazard ratio [HR], 1.25; 95% confidence intervals [CIs], 1.07-1.46; P = 0.006). Significant interaction was observed between sex and aetiology, with females showing higher mortality (HR 1.51; 95% CIs, 1.12-2.04; P = 0.007) and composite outcomes (HR 1.48; 95% CIs 1.15-1.91; P = 0.002) in degenerative disease (P for interaction = 0.021 and 0.016, respectively). Multivariate Cox regression demonstrated female sex as an independent risk factor for composite valve-related adverse outcomes (adjusted HR, 1.46; 95% CIs, 1.04-2.04; P = 0.028). CONCLUSIONS: Significant sex-based differences exist in MV disease patient characteristics and surgical outcomes, with females experiencing worse results, particularly in degenerative disease. Female sex was an independent risk factor for composite valve-related adverse outcomes after MV surgery. These differences suggest the need for sex-specific diagnostic criteria to reduce the disparities in patients with MV disease.