Mitral Valve Repair vs. Replacement by Different Etiologies　- A Nationwide Population-Based Cohort Study.

BACKGROUND: When mitral valve (MV) surgery is indicated, repair is preferred over replacement; however, this preference is not supported by evidence from clinical trials. Furthermore, the benefits of MV repair may not be universal for all etiologies of MV disease.Methods and Results: This study identified a total of 18,428 patients who underwent MV repair (n=4,817) or MV replacement (n=13,611) during 2001-2018 from Taiwan's National Health Insurance Research Database. These patients were classified into 4 etiologies: infective endocarditis (IE, n=2,678), rheumatic heart disease (RHD, n=4,524), ischemic mitral regurgitation (IMR, n=3,893), and degenerative mitral regurgitation (DMR, n=7,333). After propensity matching, all-cause mortality during follow-up was lower among patients receiving MV repair than among patients receiving MV replacement in the IE, IMR, and DMR groups (hazard ratio [HR]=0.72, 95% confidence interval [CI]: 0.55-0.93; HR=0.82, 95% CI: 0.73-0.92; and HR 0.73, 95% CI: 0.64-0.84, respectively). However, in the RHD group, the MV reoperation rate was higher after MV repair than after MV replacement (subdistribution HR=1.91, 95% CI: 1.02-3.55).

CONCLUSIONS: In comparison with MV replacement, MV repair was associated with a lower late mortality in patients with IE, IMR, and DMR, and a higher risk of reoperation in patients with RHD.