MitraClip therapy for degenerative mitral regurgitation - 12 months results from the ACCESS-Europe Phase I trial

Objectives: Interventional mitral valve repair using the MitraClip device has been established as an alternative treatment option for patients deemed inoperable or at high surgical risk by an interdisciplinary heart team. We report 12-month clinical and functional outcomes following treatment with the MitraClip device in patients with degenerative mitral regurgitation (DMR).

Methods: The MitraClip Therapy Economic and Clinical OutcomesStudy Europe (ACCESS-EU) Study has completed enrollment of 567 patients as of April, 2011, 117 of whom were DMR. Baseline demographics, procedural and acute safety results at 30 days and survival at 12 months were separately evaluated in the DMR subset. Furthermore, effectiveness results, defined by reduction in MR, and improvement in clinical outcomes based on changes in New York Heart Association (NYHA) functional class, six-minute walk test (6MWT), and quality-of-life data were assessed. DMR patients were stratified into high- and low-risk subgroups (logistic European System of Cardiac Operative Risk Evaluation I (logEuroSCORE I ≥ or  < 20% respectively) and differentially evaluated.

Results: 117 DMR patients underwent the MitraClip procedure with a 94.9% rate (111/117) of successful clip implantation. Baseline characteristics and co-morbidities included NYHA Class III/IV (74%), left ventricular ejection fraction (LVEF)  < 40% (9%), prior cardiac surgery (24%) and prior myocardial infarction (MI) (22%). Mean logEuroSCORE I was 15.5 ± 13.3%. Mortality at 30 days and 12 months was 6.0% and 17.1% respectively. At 12 months, 74.6% (53/71) of patients in follow-up achieved MR ≤ grade 2+ and 80.8% (63/78) were in NYHA functional class I/II. Both Minnesota Living with Heart Failure questionnaire (MLHFQ) scores and 6MWT distance improved significantly at twelve months compared to baseline (p = 0.03 and p < 0.0001, respectively).

Conclusions: The MitraClip procedure resulted in significantly reduced MR severity and improvements in clinical outcomes at 12 months in selected patients with severe DMR. MitraClip therapy may serve as a complementary non-surgical therapeutic option for DMR patients who are considered at high risk or ineligible for surgery by an interdisciplinary dedicated heart team. Interventional treatment should be indicated following discussion of patients in an interdisciplinary conference of cardiologists and cardiac surgeons as suggested by current international guidelines.