Severe mitral regurgitation requiring surgery: comparison of repair versus replacement

Abstract Background According to ACC/AHA, ESC/EACTS and NICE UK Guidelines for the Management of Valvular Heart Diseases, when surgery is considered for primary mitral valve disease and mitral valve repair is expected to be durable according to the Heart Team evaluation, mitral valve repair is preferred over replacement as it is associated with better survival 1-3. When repair is not feasible, experts advocate for mitral valve replacement with preservation of the subvalvular apparatus. These guideline recommendations are based solely on observational studies. In secondary mitral valve regurgitation, the advantage of mitral valve repair is less clear 4. Purpose This study aims to compare outcomes of repair and replacement in all aetiologies of severe mitral regurgitation in a tertiary cardiothoracic centre. Methods We compared the outcomes of 1751 consecutive patients (median age 69 IQR, 60-75) who underwent first MV repair (n=1249, 71%) or replacement (n=503, 29%) for mitral regurgitation between 2000 and 2021. Patients undergoing aortic valve replacement and those with MV stenosis or mixed MV disease were excluded. Coronary bypass was performed in 36% of patients and 23% required tricuspid repair. Median follow-up was 7.1 (IQR, 3.6-11.6) years. To balance the cohorts, we used genetic matching with replacement which yielded 419 pairs of patients well-matched across 27 covariates (Figure 1) [5. Results Comparing the outcomes of mitral valve replacement to repair in the matched sample, we observed more frequent blood transfusion (29% vs 21%, p=0.013), longer intensive care unit (median 1 day IQR, 1-2 vs 1 IQR, 1-1, p=0.027) and post-operative length of stay (10 7-15 vs 9 days IQR, 7-12, p=0.002) . Regarding complications, we observed a similar rate of multiorgan failure, pulmonary and gastrointestinal complications. On the other hand, there were more strokes and transient ischaemic attacks in the mitral replacement group (6.7% vs 0.6%, p0.001). In matched groups, MV replacement was associated with higher risk of mortality at 90-day (HR: 2.36, 95% CI: 1.31-4.25) and long-term follow-up (HR: 1.32, 95% CI 1.09-1.59) compared to MV repair (Figure 2). Repair was better in patients with degenerative mitral regurgitation, those = 70 years old and elective cases. Patients 70 years old, these with infective endocarditis, functional regurgitation and urgent cases had similar outcomes with either technique. Conclusion This study adds to the body of evidence supporting repair over replacement and broadens current understanding of early complications showing higher rate of cerebrovascular complications in MV replacement compared to repair. Balance before and after matching. Kaplan-Meier survival curves.