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 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 2-year follow-up results show both approaches reduced MR, and meaningful clinical benefits persisted, said Dr. Feldman of the NorthShore University HealthSystem in Evanston, Ill.
Clinical outcome measures at 2 years showed MR grade and left ventricular (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.
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%. Approximately half of the patients had New York Heart Association (NYHA) functional class III or IV heart failure.
At the meeting, Dr. Feldman presented two analyses of the 2-year data. The composite primary efficacy endpoint was freedom from death, MV surgery for valve dysfunction (for device patients) or re-operation (for surgery patients), and MR greater than 2+ at 12 months.
In the intention-to-treat analysis, the primary composite endpoint was met at 2 years by 52% of the percutaneous group and by 66% of the surgery group; in the 1-year analysis, these figures were 55% and 73%, respectively.
More patients receiving the clip later underwent MV surgery (22%) compared to the few patients in the surgery arm who required re-operation (3.6%). There was no significant difference in mortality or recurrent MR.
In the second analysis, there was no statistical difference in the effectiveness endpoint between the two arms of the study. "When subsequent surgery within 90 days on device patients is considered a success, we see similarly stable results at 1 and 2 years," he noted.
In this analysis, the primary endpoint was met at 2 years by 63% of the percutaneous group and by 66% of the surgery group. By removing the subsequent need for MV surgery as an end point event, 6.2% of the percutaneous group and 3.6% of the surgery group had MV surgery or re-operation.
There was no difference in the Kaplan-Meier mortality plot for the intention-to-treat analysis at any time point, he stressed. At 1 year, 95% of the patients in each arm were alive; at 2 years, 91% of the surgery arm and 90% of the percutaneous arm were still alive.
Freedom from MV surgery/re-operation, however, favored the surgical arm: 96% versus 78% at 2 years. The "need for surgery in patients in the clip group was almost entirely in the first several months; after 6 months the curves overlapped at 1 and 2 years," he observed. "Importantly, 78% of device patients are free from MV surgery at 2 years." When early failures were excluded, there were no differences in need for MV surgery or reoperation.
At a press conference, Dr. Feldman explained that the two analyses "answer different questions." "The intention-to-treat analysis gives the patient the odds of success with the clip at the end of the year," he said. "It tells them that 78% will be free of the need for surgery at 2 years, and 97% will have NYHA functional class I or II."
The second analysis answers the question, ‘What if I am in the 20% needing surgery?’ It counts the combined strategy of the clip, with surgery as needed.
Dr. Feldman reported consulting and research monies from Abbott Vascular. ☐