Sex-related differences in clinical outcomes after valve-in-valve transcatheter mitral valve replacement

Background Valve-in-valve (ViV) Transcatheter Mitral Valve replacement (TMVR) is an alternative to redo surgery in failed surgical bioprosthesis. The impact of sex on clinical outcomes of patients undergoing ViV TMVR remains unclear. Objective The aim of this study was to investigate sex differences in clinical characteristics and outcomes in patients undergoing ViV TMVR. Methods We prospectively enrolled consecutive patients who underwent transseptal valve-in-valve transcatheter mitral valve replacement (ViV TMVR) using a SAPIEN prosthesis between 2011 and 2024. The primary endpoint was a composite of all-cause mortality, hospitalization for heart failure, or mitral bioprosthetic valve dysfunction. Bioprosthetic valve dysfunction was defined as a composite of: (1) structural or non-structural valve deterioration resulting in a mean mitral transvalvular gradient ≥10 mmHg, moderate or severe mitral regurgitation, or the need for repeat mitral intervention; (2) valve thrombosis, defined as at least one thickened leaflet with restricted motion or a mass suggestive of thrombus confirmed by transesophageal echocardiography or cardiac computed tomography; or (3) infective endocarditis, defined according to modified Duke criteria, or confirmed by histopathology/microbiology at reoperation or autopsy. Sex-related differences in outcomes were assessed using multivariable Cox proportional hazards models. Results Among the 138 patients included, 92 were women (66.7%). The mean age was 66.6 ± 15.9 years for men versus 61.5 ± 21.8 years for women (p = 0.12). The mean EuroSCORE II was 11.2% ± 15.6 in men and 11.7% ± 11.3 in women (p = 0.84). Females were more likely to receive smaller prostheses, with a significant difference in size distribution between sexes (80.4% vs. 56.0% Size 29 in men and women respectively, p = 0.01). Male patients were more frequently required prosthesis post-dilation (43.5% vs. 20.0%, p < 0.01). There was no difference in technical success between sexes with 100% of men and 95.4% experienced technical success (p = 0.35). At one year, female sex was associated with a lower risk of the primary composite outcome (26.1% in women vs. 43.5% in men; adjusted hazard ratio [aHR]: 0.53, 95% CI: 0.28–0.99, p = 0.04) (Figure 1) and experienced lower rates of heart failure rehospitalization (3.9% vs. 23.6%; aHR: 0.22, 95% CI: 0.05–0.86, p = 0.03) and valve thrombosis (2.5% vs. 17.2%; aHR: 0.12, 95% CI: 0.02–0.70, p = 0.02). Conclusions In patients undergoing ViV TMVR, female sex was associated with a lower rate of the composite of death, rehospitalization for heart, mitral valve dysfunction or structural valve disease at one year. Sex does not appear to impact procedural or haemodynamic outcomes.