Long-Term Outcomes of Open Mitral Commissurotomy vs Mechanical Mitral Valve Replacement in Rheumatic Mitral Stenosis

Mechanical mitral valve replacement (MVR) is widely performed for severe rheumatic mitral stenosis (MS) but requires lifelong anticoagulation and carries prosthesis-related risks. Open mitral commissurotomy offers a valve-preserving alternative, yet contemporary long-term data are scarce. We compared long-term outcomes of open mitral commissurotomy and MVR in severe MS.

We retrospectively analyzed 249 patients undergoing mitral valve surgery for severe rheumatic MS (1995-2021): open mitral commissurotomy (n = 58) and MVR (n = 191). The primary outcome was a composite of all-cause death, mitral valve reoperation, major bleeding, stroke, heart failure readmission, and infective endocarditis. Propensity score matching adjusted for baseline differences.

Mean follow-up was 11.4 ± 7.0 years. In the matched cohort, 20-year composite outcome incidence was similar between open mitral commissurotomy and MVR (36.9% vs 44.6%; subdistribution hazard ratio (sHR), 0.78; 95% CI, 0.42-1.45; P = .429). Major bleeding was lower with open mitral commissurotomy (4.4% vs 22.5%; sHR, 0.22; P = .047), and infective endocarditis occurred only after MVR (0% vs 2.4%). Mitral valve reoperation tended to be more frequent in the open mitral commissurotomy group (16.7% vs 5.7%; sHR, 3.04; P = .137), but the difference was not statistically significant. In open mitral commissurotomy, mitral valve area increased from 0.90 ± 0.14 cm² preoperatively to 1.56 ± 0.31 cm² at 15 years (P < .001), and transmitral pressure gradient decreased from 11.4 ± 7.3 mm Hg to 4.6 ± 1.9 mm Hg (P < .001).

In patients with severe MS, open mitral commissurotomy provides comparable long-term clinical outcomes to MVR and is associated with fewer bleeding events and no infective endocarditis. These findings support open mitral commissurotomy as a reasonable valve-preserving option in selected patients.