SAN DIEGO – Among a carefully selected subset of heart failure patients and severe secondary mitral regurgitation, transcatheter mitral valve repair with the MitraClip reduced hospitalizations for heart failure by 47%, and death from any cause by 38% over 24 months, compared with maximal medical therapy alone.
Dr. Gregg W. Stone
That’s according to a randomized, open-label trial presented at the Transcatheter Cardiovascular Therapeutics annual meeting.
The number needed to treat to prevent one heart failure (HF) hospitalization within 2 years was three; the number needed to treat to save one life was six. Only about 3% of patients had a device complication within 12 months of placement in the study, dubbed COAPT (the Heart Failure Patients with Functional Mitral Regurgitation Trial).
COAPT patients had grade 3+ or 4+ secondary mitral regurgitation, with a mean effective regurgitant orifice area (EROA) of 41 mm2. Their left ventricles were dilated, but not huge, with a mean left ventricular end-diastolic volume of 101 mL/m2. “We estimate that’s about 10% of heart failure patients,” said lead investigator and interventional cardiologist Gregg W. Stone, MD, a professor of medicine at Columbia University, New York.
MitraClip placement was performed in high-volume centers by experienced operators, and patients were on maximally tolerated doses of guideline-directed medical therapy, as per the 2013 American College of Cardiology/American Heart Association heart failure management guidelines. There was very little variation in treatment regimens during the 2-year trial (J Am Coll Cardiol. 2017;70:776-803).
Those parameters matter. Among HF patients who did not fit them in the recent Mitra-FR trial in France, MitraClip did not reduce rates of death or unplanned hospitalization (N Engl J Med. 2018 Aug 27. doi: 10.1056/NEJMoa1805374).
COAPT and Mitra-FR investigators said at the meeting that the studies are complimentary, not conflicting, because together, they define secondary mitral regurgitation (MR) patients who will and will not benefit from the device.
MR was less severe in Mitra-FR, with a mean EROA of 31 mm2, but left ventricles were more dilated, with a mean left ventricular end-diastolic volume of 135 mL/m2. Patients were on more real-world drug regimens that varied over the course of the trial. Also, the lower implantation rates and higher complication rates in Mitra-FR “suggests perhaps greater experience of the COAPT operators,” said Dr. Stone, who also is the director of cardiovascular research and education at the Center for Interventional Vascular Therapy at New York-Presbyterian Hospital/Columbia University Medical Center.
In short, “they were a different patient population than were enrolled in COAPT,” he said at the meeting, sponsored by the Cardiovascular Research Foundation, which Dr. Stone also codirects.
There was great excitement at TCT about COAPT because there was a startling benefit for patients who previously had few options. But many speakers worried that the hype surrounding the trial will drown out the critically important message about patient selection and that the clip will be used in HF patients who don’t fit the COAPT profile.
They also said that the emerging picture of benefit in patients with less ventricular dilation but more mitral regurgitation needs to be fleshed out and better quantified.
COAPT randomized 302 patients to MitraClip on a background of guideline-directed therapy and 312 to guideline-directed therapy alone. Participants who had mitral regurgitation caused by left ventricular dysfunction, were not surgical candidates, and remained symptomatic despite optimal treatment.
The annualized rate of all hospitalizations for HF within 24 months was 35.8% per patient-year in the device group, as compared with 67.9% per patient-year in the control group, for a relative reduction of 47% (P less than .001).
Death from any cause within 24 months occurred in 29.1% of the patients in the device group and 46.1% in the control group, yielding a reduction of 38% (P less than .001).
“We didn’t cure patients by fixing their MR. They still had 29% 2-year mortality, but we did markedly improve their quality of life. The only subgroup that didn’t benefit were patients that had an EORA of less than 30 mm2 and end diastolic volume greater than the median” of 96 mL/m2, which was “fascinating,” Dr. Stone said, and fit the emerging picture.
Mitral regurgitation grade fell to 1+ or lower in 82% of patients after clip placement and remained there in the majority of survivors at 2 years.
For a long time, “HF experts thought MR was just a marker of severe left ventricular dysfunction. What I think we see here is that secondary MR is not just a bystander. It contributes to the abnormal pathophysiology of these patients,” he said.
The trial was sponsored by MitraClip’s maker, Abbott. The company participated in site selection, management, and data analysis. Dr. Stone disclosed that his employer, Columbia University, receives royalties from Abbott for sale of the clip. Several fellow investigators disclosed grants, fees, and other financial ties to the company.
Simultaneously with the COAPT presentation, the results were published online (N Engl J Med. 2018 Sep 23. doi: 10.1056/NEJMoa1806640).
Mitra-FR was funded by the French Ministry of Health and Research and Abbott.