Transcatheter Repair of Functional Mitral Regurgitation in Heart Failure Patients　- A Meta-Analysis of 23 Studies on MitraClip Implantation.

Background: The aim of this study was to investigate long-term survival, clinical status, and echocardiographic findings of patients with severe functional mitral regurgitation (FMR) undergoing MitraClip (MC) treatment and to explore the role of baseline features on outcome. Methods and Results: Randomized and observational studies of FMR patients undergoing MC treatment were collected to evaluate the overall survival, New York Heart Association (NYHA) class and echocardiographic changes after MC treatment. Baseline parameters associated with mortality and echocardiographic changes were also investigated. Across 23 studies enrolling 3,253 patients, the inhospital death rate was 2.31%, whereas the mortality rate was 5.37% at 1 month, 11.87% at 6 months, 18.47% at 1 year and 31.08% at 2 years. Mitral regurgitation Grade <3+ was observed in 92.76% patients at discharge and in 83.36% patients at follow-up. At follow-up, 76.63% of patients NYHA Class I-II and there were significant improvements in left ventricular (LV) volume, ejection fraction, and pulmonary pressure. Atrial fibrillation (AF) had a significant negative effect on 1-year survival (beta= 0.18 +/- 0.06; P=0.0047) and on the reduction in LV end-diastolic and end-systolic volumes (beta=-1.05 +/- 0.47 [P=0.0248] and beta=-2.60 +/- 0.53 [P=0.0024], respectively). Conclusions: MC results in durable reductions in mitral regurgitation associated with significant clinical and echocardiographic improvements in heart failure patients. AF negatively affects LV reverse remodeling and 1-year survival after MC treatment.