Comparison of mitral valve repair vs. replacement for mitral valve regurgitation

BACKGROUND: Mitral regurgitation (MR) is a prevalent valvular abnormality categorized as primary or secondary based on aetiology. Surgical intervention, particularly mitral valve repair, is often preferred over replacement due to its association with better outcomes. However, the benefits of repair vs. replacement, especially in secondary MR, remain debated. OBJECTIVES: This study aims to evaluate the long-term survival and reoperation rates in patients undergoing mitral valve repair compared to mitral valve replacement for MR in a cardiothoracic surgery unit in North-West England and in subgroups with degenerative and secondary aetiology. METHODS AND RESULTS: We analysed 1724 eligible patients undergoing first-time mitral valve surgery (repair: n = 1243; replacement: n = 481) between 2000 and 2021. The primary outcome was all-cause mortality. Genetic matching and overlap weighting were used to balance baseline characteristics. Median follow-up was 7.1 years. In the matched cohort, mitral valve replacement was associated with higher rates of blood transfusion (29% vs. 22%), longer Intensive Care Unit (ICU) stays, and more strokes (3.7% vs. 0.4%). While 90-day mortality did not differ significantly between groups, long-term follow-up showed a survival advantage for repair [Hazard ratio: 1.32, 95% confidence interval: 1.08-1.63]. Although repair had higher reoperation rates (4.3% vs. 2.1%), the composite of death or reoperation did not differ significantly. In the degenerative MR subgroup, repair showed superior long-term survival, whereas in secondary MR, no significant survival difference was observed between strategies. CONCLUSION: Among patients suitable for either surgical strategy, mitral valve repair showed better long-term survival compared to replacement, particularly in degenerative MR. However, this advantage was not observed in secondary MR.