Comparison of a novel mechanical valve versus stented bioprosthetic valves for isolated mitral valve replacement in patients older than 65 years

Objective: To compare early and long-term clinical outcomes of bioprosthetic versus mechanical (On-X) mitral valve replacement (MVR) in patients aged 65 years and older. Methods: This single-center retrospective study included consecutive patients equal to or older than 65 years underwent isolated MVR from 2005 to 2023. A propensity score-matched analysis was performed to compare early-and long-term clinical outcomes between patients with bioprostheses and mechanical On-X valve. Results: A total of 330 patients were included, of whom 232 (70.3%) experienced bioprosthetic mitral valve replacement (BMVR group) and 98 (29.7%) mechanical mitral valve replacement (MMVR group) with On-X prosthesis. Propensity score analysis allowed to match 98 patients from each group. In the matched cohorts, the overall survival at 1, 5, and 10 years was 97.7%, 86.5%, and 69.5% for the MMVR group and 89.6%, 80.8%, and 62.5% for the BMVR (log-rank test: 1.88, P = .170). The 1-, 5-, and 10-year freedom from reoperation, endocarditis, pacemaker implantation, and hemorrhagic events were comparable between the 2 groups. Conclusions: In patients older than 65 years requiring isolated MVR, the use of On-X mechanical prosthesis showed comparable long-term outcomes over bioprostheses. (JTCVS Open 2025;26:85-93)