Final 5-Year Results Presented for COAPT Trial of Abbott's Mitra Clip

March 5, 2023—The American College of Cardiology (ACC) announced the presentation of data from the COAPT trial of transcatheter edge-to-edge repair (TEER) using the MitraClip (Abbott) in patients with secondary mitral regurgitation (MR). The trial showed that treatment with the MitraClip was safe and cut the rate of hospitalizations for heart failure by 47% and reduced deaths from any cause by approximately 30% after 5 years of follow-up. The study was funded by Abbott.

The findings were presented by Gregg W. Stone, MD, at ACC.23/WCC, the ACC's annual scientific session together with the World Congress of Cardiology held March 4-6, 2023, in New Orleans, Louisiana. The study was simultaneously published by Dr. Stone, et al online in The New England Journal of Medicine.

"These final results show that in a very sick population with mitral valve dysfunction secondary to heart failure, transcatheter mitral valve repair was extremely safe and significantly reduced both hospitalizations due to heart failure and deaths from heart failure or all causes," commented Dr. Stone in the ACC press release. However, Dr. Stone advised that these patients had a high rate of adverse events even after successful mitral valve repair, indicating the need for further advances to treat these high-risk patients.

"When the left ventricle becomes enlarged, that in turn deforms the mitral valve so that it no longer closes properly," noted Dr. Stone, who is Director of Academic Affairs for the Mount Sinai Health System and Professor of Medicine (Cardiology) and Population Health Science and Policy at the Icahn School of Medicine at Mount Sinai in New York, New York.

As summarized in the ACC press release, the COAPT trial enrolled 614 patients (average age 72 years; 36% women) in the United States and Canada who had left ventricular failure, severe MR, and symptoms of heart failure (fatigue, breathlessness) despite being on the best available medical therapy, which at the time consisted of three heart failure medications. All patients in the trial continued to take their prescribed heart failure medications.

Half of the patients were randomly assigned to undergo a TEER procedure that used MitraClip to reduce MR. The other half, who did not undergo TEER, served as a control group.

The trial’s primary effectiveness endpoint was all hospitalizations for heart failure within 2 years of follow-up. The primary safety endpoint was whether more than 88% of patients treated with TEER experienced no complications from the device within the first year.

In 2018, the 2-year results from COAPT were presented and published by Dr. Stone et al in The New England Journal of Medicine (2018;379:2307–2318).

The 2-year data showed a 47% reduced risk of hospitalization for heart failure among patients who received the MitraClip, compared with the control group. The primary and secondary endpoints of the study were met. Approximately 97% of TEER patients had no complications within the first year. Within 2 years, 29% of TEER patients died from any cause, compared with 46% of patients in the control group.

The current presentation, which reported the final results for all patients after 5 years of follow-up, showed that death or hospitalization for heart failure occurred in 73.6% of patients undergoing TEER compared with 91.5% of those in the control group, which was a 47% reduction. The reduced risk of death from any cause for TEER patients compared with controls was 28%.

The relative benefits of TEER declined after 3 years, in large part because after 2 years patients in the control group patients were allowed to cross over to undergo TEER.

In the ACC press release, Dr. Stone observed, "MitraClip made a profound difference for patients with heart failure and severe MR. Based on these findings, appropriate patients should be treated with MitraClip as early as possible. However, nearly three in four patients still died or were hospitalized for heart failure within 5 years, even after successful MitraClip, because treating the regurgitant mitral valve does not improve their underlying left ventricular dysfunction. We need to develop better therapies for advanced heart failure if the prognosis of this high-risk patient population is to be further improved."

Dr. Stone noted that one limitation of the study is that it was not blinded; however, independent experts assessed the hospitalizations, deaths, and other adverse events in the study based on specific criteria documented in the patient’s chart. The study’s findings also apply only to patients with mitral valve regurgitation secondary to left ventricular failure who were treated with the MitraClip device.

Also, patients enrolled in the COAPT trial received the first-generation MitraClip. Since then, there have been technological advances in the device. The currently marketed device, which represents the fourth generation of the technology, can reduce mitral regurgitation further, Dr. Stone said. Also, a new class of medications for heart failure, SGLT2 inhibitors, became available in 2020 after the trial was nearly finished, reported ACC.