Percutaneous mitral valve repair for secondary mitral valve regurgitation: A systematic review and meta-analysis

The first two randomized control trials (RCTs) studying the role of MitraClip in patients with secondary mitral regurgitation (MR) had antagonizing results. We, therefore, performed an updated meta-analysis of RCTs and propensity score-matched observational studies investigating the role of MitraClips in patients with secondary MR. A novel method of Kaplan Meier Curve reconstruction from derived individual patient data will be used to compare the survival probability of control groups in COAPT and MITRA HF trail, and hence, access inter-study heterogeneity.

Medline and Cochrane databases was used for systematic search. We used the Mantel-Haenszel method with a random-effect model to calculate risk ratio (RR) with 95% confidence interval (CI) and inverse variance method with a random-effect model to calculate the mean difference (MD) with 95% confidence interval (CI). We used a fixed-effect approach for meta-regression.

MitraClip reduced the risk of all-cause mortality [RR: 0.72, CI: 0.55-0.95, P value = 0.02, I2 = 55%, χ²P-value = 0.08] and readmission [RR: 0.62, CI: 0.42-0.92, P value = 0.02, I² = 90%, χ²P-value<0.01] at two years follow-up. There was no effect of MitraClip on change in cardiovascular mortality and 6 m walking distance at 12 months follow-up. Meta-regression indicated left ventricular end diastolic volume and age among the factors affecting outcomes. Reconstructed Kaplan Meier curves confirmed considerable heterogeneity among patients randomized in MITRA HF and COAPT trial.

The present meta-analysis confirms the beneficial role of percutaneous mitral valve repair in patients with secondary MR. However, all the results were associated with considerable heterogeneity.