Journal of Invasive Cardiology

In EVEREST II, the MitraClip shows superior safety, similar effectiveness

ACC 2010, Atlanta, Georgia. A catheter-mounted device that acts like a clothespin to clip together the flaps of a leaky heart valve is a safe and effective alternative to open-chest surgery in selected patients with mitral regurgitation, according to research presented today at the American College of Cardiology’s 59th annual scientific session. ACC.10 is the premier cardiovascular medical meeting, bringing together cardiologists and cardiovascular specialists to further advances in cardiovascular medicine.

The Endovascular Valve Edge-to-Edge Repair Study (EVEREST II) involved patients with significant leakage (regurgitation) through the mitral valve, which keeps blood from flowing back to the left atrium from the left ventricle. The study showed that patients treated with the MitraClip valve repair system were
one-sixth as likely as surgical patients to experience a serious complication within 30 days of the procedure. After 1 year, the clinical effectiveness of the two treatment strategies appeared similar.

“As clinicians, we have seen our patients transformed from highly symptomatic to highly functional with a catheter procedure – and without a long hospital stay or a long recovery period,” said Ted Feldman, MD, director of the cardiac catheterization laboratory for NorthShore University Health System, Evanston, Illinois.

“The real excitement is seeing our experience with individual patients reflected in trial results in a clear way.”

More than 250,000 people in the United States are diagnosed with mitral regurgitation each year. Surgical repair or replacement of the defective heart valve is considered standard treatment, but it involves opening the chest and cutting into the heart. Not all patients can withstand such major surgery and those who do face a long recovery, typically about six weeks. Now, the MitraClip procedure offers a minimally invasive alternative that typically allows patients to engage in normal daily activities within a week.

Mounted on the end of a catheter, the MitraClip is threaded through the femoral vein in the groin and into the right atrium. A needle puncture in the wall separating the upper chambers of the heart enables the catheter to pass into the left atrium, where the clip is opened up like a clothespin. It is then passed through the mitral valve into the left ventricle. When the heart contracts, the flaps, or leaflets, of the mitral valve fall into the clip, which is then closed, pinning the edges of the leaflets together at their centers. The result is a bow-tie-shaped opening that permits blood flow from the left atrium to the left ventricle during relaxation of the heart, and enables the valve to close more effectively during contraction, rather than
allowing leakage of blood backward into the left atrium.
The EVEREST II study was designed to evaluate the safety and effectiveness of the MitraClip procedure in comparison with open-chest mitral valve surgery. For the study, researchers from 37 North American medical centers recruited 279 patients who fit the American College Cardiology/American Heart Association guidelines for mitral valve surgery (moderate-to-severe [Grade 3+] or severe [Grade 4+] mitral regurgitation). Patients were randomly assigned in a 2-to-1 ratio to treatment with the MitraClip device (184 patients) or mitral valve repair or replacement surgery (95 patients). The MitraClip procedure
was successful in 137 patients, and of these, 136 were available for inclusion in the data analysis at 30 days; 79 surgical patients were available for 30-day follow up.

The comparative safety of the two procedures was gauged by major adverse clinical events (MACE) at 30 days. The 30-day MACE rate in the MitraClip group was 9.6% (representing transfusions in 8.8% and gastrointestinal complications in 0.7%), as compared with 57% in the surgery group (transfusions, 53.2%; need for a ventilator for more than 48 hours, 5.1%; urgent/emergency surgery, 5.1%; death, 2.5%; and stroke, 2.5%). The difference
between the two groups represented a highly significant finding of superior safety with the MitraClip, according to the researchers.

The comparative effectiveness of the two procedures was gauged at 12 months by freedom from a combination of death, new surgery for mitral valve dysfunction, or more than mild mitral regurgitation.
Clinical success was achieved at 12 months by 72.4% of patients treated with the MitraClip and 87.8% of those treated with surgery, a highly significant finding of the “noninferiority” of the MitraClip.

At 30 days, quality of life was significantly improved in the MitraClip group, but was worse in the surgery group. By 12 months, both groups reported significant improvement in quality of life.