Mitral valve trial offers promise for high-risk patients

Ethan C. Korngold, M.D.
Cardiologist, Providence St. Vincent Heart Clinic-Cardiology

Published October 2012

Following the successes of the transcatheter aortic valve program and PARTNER II trial, Providence Heart and Vascular Institute now offers new technologies for catheter-based repair of mitral valve regurgitation, the most common form of valvular heart disease.

The COAPT trial will evaluate the safety and effectiveness of the MitraClip mitral valve repair system to treat moderate to severe functional mitral regurgitation in symptomatic subjects for whom mitral valve surgery is too risky. This includes patients with heart failure and impaired heart function with ejection fractions as low as 20 percent.

Until recently, options have been limited for high-risk patients with mitral regurgitation, particularly those with low ejection fractions. The MitraClip system has been in development since 2003. Since then, more than 5,500 patients worldwide have undergone the procedure.

The MitraClip is a mechanical device that is a percutaneously implanted via femoral venous access with transesophageal echocardiographic guidance. There is no need to arrest the heart or perform cardiopulmonary bypass. The device grasps and coapts the mitral valve leaflets, resulting in fixed approximation of the mitral leaflets throughout the cardiac cycle. This results in a dual-orifice mitral valve with reduced mitral regurgitation.

Early clinical trials include EVEREST II RCT, which evaluated patients with degenerative and functional mitral regurgitation and compared the MitraClip to traditional, open surgical repair.

On an intention-to-treat basis, the MitraClip approach had an early safety advantage, and 78 percent of patients in the device arm were free from surgery at two years with similar clinical benefit compared to surgery.

The trial found no incidence of mitral stenosis, device embolization or device migration. Sustained reduction in mitral regurgitation was observed, although not quite to the extent of surgery. Symptomatic benefit, as evidenced by improvements in New York Heart Association functional class and quality-of-life measures, was at least as good for patients in the MitraClip device arm as for those who underwent surgery.

The authors concluded that although percutaneous repair was less effective at reducing MR than conventional surgery, the procedure was associated with superior safety and similar improvements in clinical outcomes.

Patients at high surgical risk were evaluated in the EVEREST II HR study, which demonstrated global reduction of mitral regurgitation, improved functional class and quality-of-life measures, fewer hospitalizations for heart failure and lower mortality compared to historical controls.

Patients in the COAPT trial will undergo screening at Providence St. Vincent Medical Center or Providence Portland Medical Center, beginning with transthoracic echocardiogram and followed by transesophageal echocardiogram. Participants will be managed in concert with the Center for Advanced Heart Disease and treated aggressively for heart failure, regardless of treatment assignment.

To learn more about treatment options for mitral regurgitation, including the MitraClip and the COAPT trial, contact Michelle Dixon at 503-215-6746.