Safety and efficacy of the DragonFly system for transcatheter valve repair of degenerative mitral regurgitation: one-year results of the DRAGONFLY-DMR trial

BACKGROUND: Severe degenerative mitral regurgitation (DMR) can cause a poor prognosis if left untreated. For patients considered at prohibitive surgical risk, transcatheter edge-to-edge repair (TEER) has become an accepted alternative therapy. The DragonFly transcatheter valve repair system is an innovative evolution of the mitral TEER device family to treat DMR. AIMS: Herein we report on the DRAGONFLY-DMR trial (ClinicalTrials.gov: NCT04734756), which was a prospective, single-arm, multicentre study on the safety and effectiveness of the DragonFly system. METHODS: A total of 120 eligible patients with prohibitive surgical risk and DMR ≥3+ were screened by a central eligibility committee for enrolment. The study utilised an independent echocardiography core laboratory and clinical event committee. The primary endpoint was the clinical success rate, which measured freedom from all-cause mortality, mitral valve reintervention, and mitral regurgitation (MR) >2+ at 1-year follow-up. RESULTS: At 1 year, the trial successfully achieved its prespecified primary efficacy endpoint, with a clinical success rate of 87.5% (95% confidence interval: 80.1-92.3%). The rates of major adverse events, all-cause mortality, mitral valve reintervention, and heart failure hospitalisation were 9.0%, 5.0%, 0.8%, and 3.4%, respectively. MR ≤2+ was 90.4% at 1 month and 92.0% at 1 year. Over time, left ventricular reverse remodelling was observed (p<0.05), along with significant improvements in the patients' functional and quality-of-life outcomes, shown by an increase in the New York Heart Association Class I/II from 32.4% at baseline to 93.6% at 12 months (p<0.001) and increased Kansas City Cardiomyopathy Questionnaire (KCCQ) score of 31.1±18.2 from baseline to 12 months (p<0.001). CONCLUSIONS: The DRAGONFLY-DMR trial contributes to increasing evidence supporting the safety and efficacy of TEER therapy, specifically the DragonFly system, for treating patients with chronic symptomatic DMR 3+ to 4+ at prohibitive surgical risk.