The value of adding sub-valvular procedures for chronic ischemic mitral regurgitation surgery: a meta-analysis

Background: The most performed repair technique for the treatment of chronic ischemic mitral regurgitation in patients referred for bypass grafting remains restricted annuloplasty. However, it is associated with a high rate of failure, especially if severe tenting exists. Objectives: To understand if adjunctive sub-valvular mitral procedures may provide better repair performance. Methods: A systematic literature review identified six studies of which five fulfilled the criteria for meta-analysis. Outcomes for a total of 404 patients (214 had adjunctive sub-valvular procedures and 190 restricted annuloplasty) were meta-analyzed using random effects modeling. Heterogeneity and subgroup sensitivity analysis were assessed. Primary endpoints were: late recurrence of moderate mitral regurgitation, left ventricle remodeling and coaptation depth at follow-up. Secondary endpoints were: early mortality, mid-term survival and operative outcomes. Results: Sub-valvular procedure technique was associated with a significantly lower late recurrence of mitral regurgitation (Odds ratio (OR) 0.34, 95% Confidence Interval (CI) [0.18, 0.65], p=0.0009), smaller left ventricle end-systolic diameter (Weighted Mean Difference (WMD) -4.06, 95% CI [-6.10, -2.03], p=0.0001) and reduced coaptation depth (WMD -2.36, 95% CI [-5.01, -0.71], p=0.009). These findings were consistent, even in studies that included patients at high risk for repair failure (coaptation depth >10 mm and tenting area >2.5 cm(2)). A low degree of heterogeneity was observed. There was no difference in terms of early mortality and mid-term survival; sub-valvular technique was associated with prolonged cardiopulmonary and cross-clamp time. Conclusions: Adding sub-valvular procedures when repairing ischemic chronic mitral valve regurgitation may be associated with better durability, even in the case of the presence of predictors for late failure. Perspective: Surgical sub-valvular adjunctive procedures have to be considered in the case of the presence of echocardiographic predictors for late failure.