Transcatheter Mitral Valve Implantation Systematic Review: Focus on Transseptal Approach and Mitral Annulus Calcification.

INTRODUCTION: This systematic review was performed to evaluate the results of transcatheter mitral valve implantation (TMVI) in the native mitral valve. EVIDENCE ACQUISITION: Medline, EMBASE, and the Cochrane Central register were systematically searched for studies that reported results of TMVI in mitral valve regurgitation and/or stenosis and mitral annular calcification. To improve the sensitivity of the literature search, we performed citation chasing in Google Scholar, Scopus, and Web of Science. EVIDENCE SYNTHESIS: Twelve studies reporting results of TMVI in mitral regurgitation were retrieved and included 347 patients. The transseptal approach represented 28% of cases. Secondary mitral regurgitation was the predominant indication in 63% of cases. Thirty-day mortality was 11% and was lowered with the transseptal approach (7%). Technical success was 92%. Surgical conversion was needed in 5% of patients. Only one patient presented moderate to severe mitral regurgitation. These hemodynamic results were sustainable up to one year of follow-up. Three series focused on results of TMVI in mitral annulus calcification including 167 patients. Only nine patients were treated with TMVI dedicated prosthesis. Eighty-seven patients had their prosthesis delivered through a transseptal approach. Mitral stenosis was present in 63% of cases. Thirty-day mortality was 24%, and none with TMVI prosthesis. Technical success was achieved in 71% of cases and was improved by using TMVI prosthesis (89%). The main complication was left ventricular outflow tract obstruction (20%). Post procedural moderate to severe mitral regurgitation was observed in 4% of cases. CONCLUSION: TMVI seems to be feasible, achieving good technical success and predictable and durable MR reduction.