Safety and efficacy of the MitraClip® system for severe mitral regurgitation: a systematic review

Background: The MitraClip® system is a newer percutaneous device that has shown promising results but data on its safety and efficacy in low- and high-surgical risk populations continues to evolve. We performed a systematic review of the published studies reporting the safety and efficacy of MitraClip® implantation for treatment of moderate to severe and severe mitral regurgitation (MR).

Methods: Reviewers independently searched for relevant articles in Medline and abstracted clinical information based on pre-defined criteria and end-points. Patients were classified as low- or high-surgical risk for conventional mitral valve (MV) surgery based on Society of Thoracic Surgeons score, EuroSCORE, or surgeon discretion. Primary safety outcome was 30-day mortality and primary efficacy outcomes were freedom from death, ≥3+ MR, and requirement for MV surgery during follow-up.

Results: Immediate and long-term outcomes of 16 studies, including 2980 patients (age 73.7 ± 0.6 years; 63.3% males) receiving the MitraClip®, were analyzed. Acute procedural success rate was 91.4% with a procedural mortality of 0.1%. Mortality at 30 days and long-term (310 days) follow-up was 4.2 and 15.8%, respectively and was significantly higher in the high-risk group (P = 0.003 and 0.019, respectively). Incidence of major procedural adverse outcomes was relatively low with blood transfusion accounting for most events. At follow-up, the number of patients with ≥3+ MR reduced from 96.3% to 14.7% (P < 0.001), and those with NYHA class III/IV reduced from 83.2% to 23.4% (P < 0.001).

Conclusion: MitraClip® implantation for moderate to severe or severe MR appears to be safe with a very low procedural mortality. There is significant improvement in functional outcomes although long-term mortality is high, especially in high surgical risk patients.