NEW ORLEANS – The durability and safety of treating mitral regurgitation with a percutaneous device as compared with that of surgical repair or replacement persisted at 2 years, based on an updated analysis of the EVEREST II trial results presented April 4 at the annual meeting of the American College of Cardiology.
"Our fundamental finding is that outcomes are very stable between 1 and 2 years of follow-up," Dr. Ted Feldman, principal investigator, announced at a press briefing. "The Kaplan-Meier curves for mortality and re-operation remain literally and completely flat through that time period, and clinical outcomes are durable."
Based on data from the first year of the study, percutaneous repair with the MitraClip was safer than surgery, but surgery yielded more complete reduction in mitral regurgitation (MR). (epub ahead of print, Feldman T et al. N Engl J Med 2011;April 4)
The 2-year follow-up results, presented at the meeting, show both approaches reduced MR, and meaningful clinical benefits persisted, said Dr. Feldman, who is director of the cardiac catheterization laboratory at the NorthShore University HealthSystem in Evanston, Ill.
Clinical outcome measures at 2 years showed MR grade and LV volumes remained stable between 1 and 2 years in both groups. The inter-group comparison showed a more favorable reduction in MR and a greater reduction in LV diastolic volume with surgery at 1 and 2 years, and no difference in systolic volume reduction.
Also, NYHA functional class was stable between years 1 and 2. "Interestingly, the inter-group comparison showed a more favorable NYHA class outcome at both years with the clip," he reported.
The safety profile continued to be favorable, as well. "We saw no percutaneous device embolization; no device fracture, erosion or migration; and no additional occurrence of single leaflet device attachment," he reported.
"Stability is the major message in the examination of 2-year outcomes," Dr. Feldman said. "The randomized trial represents our very early experience with the device. Our procedural rate was 86% in the trial but in the post-randomization registry is in the 96% range. We are certainly going to get better at doing this."
At a panel convened to comment on the study results, Dr. Gregg W. Stone, professor of medicine at New York Presbyterian Hospital and Columbia University, New York, said that the follow-up analysis of EVEREST II is "very well done" and has, "for the most part, shown stability and fairly comparable mortality, though 22% of patients still need surgery if they take the route of the percutaneous option."
Steven F. Bolling, professor of surgery at the University of Michigan, Ann Arbor, maintained that while EVEREST II "suffers a little from awkward analyses," the results are promising, pending the right patient selection and longer follow-up. Patients at high surgical risk and those with cardiomyopathy-associated MR would be the appropriate subset for further study in order to refine the optimal use of the device.
EVEREST II (Endovascular Valve Edge-to-Edge Repair Study) is a prospective, multicenter, randomized controlled phase II trial comparing the safety and efficacy of the MitraClip System with mitral valve surgery in the treatment of MR. The study enrolled 279 patients with 3+ or 4+ MR who were either symptomatic or were asymptomatic with a baseline left ejection fraction of 60%; 27% had functional MR and 73% had degenerative MR. Approximately half of the patients had New York Heart Association (NYHA) functional class III or IV heart failure.
The patients were randomized 2:1 to receive the MitraClip device (n = 184) or mitral valve (MV) repair or replacement (n = 95). Over 90% of the study cohort was available for the 2-year analysis.
Outcomes through 1 year (primary safety and efficacy end points) were recently reported (epub ahead of print, Feldman T et al. N Engl J Med 2011;April 4), showing increased safety with the Mitraclip device compared to surgery, but greater reduction in MR with surgery. At 30 days, major adverse events occurred in 15% of the percutaneous arm versus 48% of the surgical arm. LV function improved in both groups, as did New York Heart Association (NYHA) functional class and quality of life at 1 year.
At the meeting, Dr. Feldman presented two analyses of the 2-year data. The first was an intention-to-treat analysis, in which any MV surgery following percutaneous repair was considered an end point event. The second was a comparison of treatment strategies, in which MV surgery following unsuccessful in-hospital percutaneous repair was not considered an end point event. In the latter analysis, subsequent surgery within 90 days of the percutaneous procedure was still considered a "success" for the MitraClip.