NEW YORK – In a group of 351 high-risk surgical patients with severe mitral regurgitation (grade 3 or 4) at baseline, more than 80% were alive 1 year after transcatheter treatment with the MitraClip device if their MR was well controlled (MR grade 1+ or 2+), compared with 58% survival for those with persistent severe MR.

These results from the EVEREST II High Surgical Risk cohort were presented by Dr. Paul A. Grayburn at the 2013 Mitral Valve Conclave.

The presentation was chosen as one of the Plenary "Top 10" Abstract Presentations at the meeting.

"Many high-risk surgical patients do not undergo mitral valve surgery and therefore have no therapeutic option for MR. Percutaneous repair with MitraClip is an option for selected patients with suitable anatomy who are too high of a risk for surgery. In this study, we found that the extent of clinical benefit observed corresponds with the degree of MR reduction achieved," said Dr. Grayburn, a cardiologist at the Baylor Heart and Vascular Institute in Dallas. "MR reduction to 1+ or 2+ results in significant clinical and symptomatic improvement."

The MitraClip is a catheter-based valve repair system intended to reduce MR. The device is inserted via the femoral vein using a guide catheter, and the MitraClip implant is attached directly to the mitral valve. On March 20, 2013, the FDA’s Circulatory System Devices Advisory Panel voted by a narrow margin (5-3) in favor of the device, finding that the benefits outweighed the risks.

Data were pooled from the EVEREST II High Risk Study and the EVEREST II REALISM Continued Access Study. The mean age of the 351 patients was 76 years, with 58% of the group over age 75. At baseline, patients had significant comorbidities, including 82% with coronary artery disease, 51% with a prior myocardial infarction, 69% with a history of atrial fibrillation, and 60% with previous cardiovascular surgery. Of the 98% with heart failure, 85% were New York Heart Association (NYHA) functional class III/IV. Aside from cardiac problems, 31% had moderate to severe renal disease, and 29% had chronic obstructive pulmonary disease. Functional MR was present in 70% of the group.

With these health problems in mind, the patients were considered to be at high risk for mitral valve surgery as indicated by a Society of Thoracic Surgeons (STS) risk calculator operative mortality of 12% or more.

Mortality at 1 year was 22.8%. Looking at freedom from mortality at 1 year after treatment, 80.9% of those discharged with MR greater than or equal to 1+ and 80.3% of those discharged with an MR grade of 2+ were alive. For those discharged with a grade of 3+ or 4+, 58.4% were alive (P = .0003).

"As you can see, it is not good for you to leave the operating room after MitraClip with an MR grade of 3+ or 4+," Dr. Grayburn said at the meeting, which was sponsored by the American Association for Thoracic Surgery.

Residual MR grade also influenced other measures. For instance, patients with low levels of MR showed better left ventricular remodeling, as measured by larger changes from baseline in left ventricular end diastolic volume (LVEDV) and left ventricular systolic volume. For LVEDV, there was a 15% reduction from baseline in the group with MR greater than or equal to 1+ and a 10% reduction in the 2+ group, but no statistically significant reduction in the 3+/4+ groups.

After treatment, significantly fewer patients with an MR grade greater than or equal to 1+ were considered NYHA functional class III/IV, compared with those with MR 3+ or 4+.

Other benefits of treatment included a 54% reduction in the annual rate of hospitalization due to congestive heart failure in the 12 months after the MitraClip procedure vs. the 12 months pre-MitraClip in patients with an MR grade of 2+ at discharge, compared with no change in hospitalization rate in those discharged with MR greater than 2+. Trends were noted between better MR control and scores on the Short Form-36 (SF-36) quality of life score and the mental component score.

Dr. Grayburn emphasized that the MitraClip procedure is not for everybody but offers an option for those considered at high risk. "If you can operate on these patients, you should; then you can get their MR to null. This device is really a palliative offering for those turned down by a mitral valve surgeon at an experienced mitral valve center. At our center, many patients referred to us for MitraClip actually end up getting surgery because they turn out to be surgical candidates." At his center, Dr. Grayburn says that for every patient who gets a MitraClip, two undergo surgery.

Nevertheless, Dr. Grayburn believes that some high-risk patients who might benefit from MitraClip are unaware of this alternative. "We haven’t figured out how to capture patients with severe symptomatic MR in the general internist’s or even cardiologist’s office."

Dr. Grayburn received research support from Abbott Vascular.

EVEREST II: Tight MR control improves MitraClip patients' survival