Optimal versus suboptimal mitral valve repair: Late results in a matched cohort study

OBJECTIVES: After mitral repair for degenerative mitral regurgitation (MR), no or mild (<_1+/4+) residual MR should remain. Occasionally patients are left with more than mild residual MR (>1+/4+) for a number of reasons. The aim of this study was to assess the late implications of such a suboptimal repair in a matched cohort study. METHODS: From 2006 to 2013, a total of 2158 patients underwent mitral repair for degenerative MR in our institution. Fifty patients (2.3%) with residual MR >1+ at hospital discharge (study group) were matched up to 1:2 with 91 patients operated on during the same period who were discharged with MR <_1+ (control group). The median follow-up was 8 years (interquartile range 6.3-10.1, longest 12.7 years). A comparative analysis of the outcomes in the 2 groups was performed. RESULTS: Overall survival at 8 years was 87 ± 8% in the study group and 92 ± 3% in the control group (P = 0.23). There were 3 late deaths (6.0%) in the study group and 6 deaths (6.6%) in the control group. Freedom from reoperation was similar (P = 1.0). At 8 years the prevalence of MR >_3+ was significantly higher in the study group (15.6% vs 2.1%, P < 0.001) as was the use of diuretics, beta-blockers and angiotensin-converting enzyme inhibitors/angiotensin-receptor blockers. Interestingly, even in the control group, a gradual progression of MR was observed because 13.3% of the patients had MR >_2+ at 8 years with a significant increase over time (P < 0.001). CONCLUSIONS: Residual MR more than mild at hospital discharge is associated with lower durability of mitral repair and the need for more medical therapy in the long term. However, even an initial optimal result does not completely arrest the progression of the degenerative process.