Early outcomes of transcatheter mitral valve replacement for degenerated bioprosthesis in Japanese (MITRAL VIV study): a four-case series.

Objective: The mitral valve-in-valve procedure has been performed in the world. However, the early clinical outcomes in Japan remain unclear. Hence, we investigated the feasibility, safety, and efficacy in high-risk Japanese patients. Methods: In May 2017, we launched the present clinical study of the mitral valve-in-valve procedure (MITRAL VIV study). The study enrolled four patients (three women; age range 69–85 years) with severe mitral regurgitation due to a degenerated mitral bioprosthesis. The median Society of Thoracic Surgeons score was 8.8 (range 8.4–9.8)%. Results: In all patients, the mitral valve-in-valve procedure was successfully performed via a transapical approach at the initial attempt. The median grade of mitral insufficiency improved from grade 4 (range 3–4) to grade 1 (range 0–1) at days 7 and 30. The mean mitral pressure gradient of the median value changed from 7.0 (range 5.0–8.0) mmHg to 5.0 (range 5.0–9.5) mmHg at 7 days and 6.2 (range 4.0–11.0) mmHg at 30 days. The median New York Heart Association functional class improved from 2 (range 2–3) to 1 (range 1–3) at day 7 and to 1 (range 1–2) at day 30. We performed a bit deep implantation intentionally to avoid left ventricular outflow tract obstruction in one patient with a small aorto-mitral-annular angle. Neither mortality nor severe complications were observed at the last follow-up (range 207–513 days). Conclusions: In our experience, the safe mitral valve-in-valve procedure was feasible with cautious procedures. [ABSTRACT FROM AUTHOR]