MitraClip Treatment of Moderate-to-Severe and Severe Mitral Regurgitation in High Surgical Risk Patients ― Real-World 1-Year Outcomes From Japan ―

BACKGROUND: The MitraClip NT System was approved for marketing in Japan on October 31, 2017, and a prospective, multi-center, single-arm Post-Marketing use Surveillance (PMS) study was launched in 2018. This is the first report of the Japan PMS study with 1-year subject outcomes. METHODS AND RESULTS: A total of 500 patients were registered between April 2018 and January 2019. Patients with symptomatic chronic moderate-to-severe (3+) or severe mitral regurgitation (MR; 4+), MR with a Society of Thoracic Surgery (STS) replacement score of ≥8%, or presence of 1 pre-defined risk factor were enrolled. Primary outcome measures included acute procedural success (APS), and rate of Single Leaflet Device Attachment (SLDA) at 30 days. The overall cohort was elderly (77.9±9.48 years) with functional MR etiology in 71.6% of the subjects. The majority of subjects were New York Heart Association (NYHA) class III/IV (68.9%), with mean STS replacement score of 11.95±9.66%. The APS rate was 91.13% and the 30-day SLDA rate was 1.21%. Durable MR reduction was achieved with 88.1% of subjects at MR ≤2+ at 1 year. Significant improvement in the functional capacity was observed, with 93% of subjects at NYHA class I/II at 1 year. CONCLUSIONS: In the Japan PMS experience, the MitraClip procedure resulted in improvements in MR severity, with significantly improved functional outcomes. These results demonstrate safety and efficacy of MitraClip therapy in the eligible Japanese population.