BackgroundConsensus guidelines recommend repair over replacement for the surgical treatment of active native mitral valve infective endocarditis. However, contemporary practice and long-term outcome data are limited. MethodsMultivariable Cox regression was used to compare outcomes of 1970 patients undergoing isolated primary mitral valve repair (n = 367, 19%) or replacement (n = 1603, 81%) for active infective endocarditis between 1998 and 2010 in New York and California states. The primary outcome was long-term survival. Secondary outcomes were recurrent endocarditis and mitral reoperation. Median follow-up time was 6.6 years (range 0-12), and last follow-up date was December 31, 2015. ResultsMitral valve repair rates increased from 10.7% to 19.4% over the study period (P < .001). Patients undergoing mitral repair were younger (55 ± 15 vs 57 ± 15 years, P = .005), less likely to have congestive heart failure (46.3% vs 57.1%, P < .001), and less likely to have staphylococcal infections (21.3% vs 32.0%, P < .001). Twelve-year survival was 68.8% (95% confidence interval [CI], 62.5%-74.3%) after mitral repair, versus 53.5% (95% CI, 50.6%-56.4%) after replacement (adjusted hazard ratio, 0.71; 95% CI, 0.57-0.88; P = .002). Mitral repair was associated with lower rate of recurrent endocarditis at 12 years than replacement (4.7% [95% CI, 2.8%-7.2%] vs 9.5% [95% CI, 8.0-11.1%]; P = .03), and similar rate of reoperation (9.1% [95% CI, 6.2%-12.8%] vs 8.6% [95% CI, 7.1%-10.4%]; P = .12). ConclusionsIn active endocarditis, mitral valve repair is associated with better survival and lower risk of recurrent infection compared with valve replacement and should be the surgery of choice when feasible.