麻豆传媒

PARIS -- Percutaneous repair with the MitraClip still adds no benefit to the treatment of patients with secondary mitral regurgitation (MR) in the MITRA-FR trial, according to follow-up data extending out to 2 years.

The primary composite endpoint of all-cause death and unplanned heart failure rehospitalization continued to be equally likely between MitraClip recipients and controls who got medical treatment alone (63.6% vs 67.1%, HR 1.01, 95% CI 0.77-1.34), according to a presentation by Jean François Obadia, MD, PhD, of Hopital Cardiovasculaire Louis Pradel in Lyon, France, at the annual meeting of the .

His group's latest report was also published online in the .

But while the cumulative incidence of first heart failure hospitalization was no different between groups over the 24-month period (HR 0.97, 95% CI 0.72-1.30), there was a divergence starting around the one-year mark that did give percutaneous repair a significant advantage throughout the second year (HR 0.47, 95% CI 0.22-0.98), Obadia said.

"We may have some delayed benefit of MitraClip," he said during an ESC press conference. He cautioned, however, that this piece of the analysis was unpowered and post hoc.

"The emergence of a possible reduction in all heart failure hospitalizations in MitraClip-treated patients between one and two years is intriguing, but must be interpreted cautiously in the face of a negative trial," agreed Gregg Stone, MD, of Columbia University Medical Center/NewYork-Presbyterian and the Cardiovascular Research Foundation in New York City.

MITRA-FR's initial 1-year report was neutral at best, showing no reduction in all-cause death and unplanned heart failure rehospitalizations among those randomized to MitraClip therapy on top of medications.

Study participants were patients with symptomatic heart failure already on guideline-directed medical therapy who had been hospitalized at least once within the 12 months preceding randomization.

The trial was notable for preceding the seemingly-contradictory COAPT trial, which showed a benefit to MitraClip repair in the form of reduced heart failure hospitalizations at 24 months among patients with secondary MR. Stone was the lead investigator of that trial.

Some have tried to come up with reasons why MITRA-FR and COAPT differed so much in their results. For one, patient differences may play a role as the former trial enrolled individuals with less severe MR and more severely dilated ventricles.

But it's more complicated than just patient selection, as Obadia pointed to the difference in control-group mortality at 2 years (34% in MITRA-FR and 46% in COAPT).

Better use of medication in MITRA-FR may help explain this difference, according to ESC session discussant Rebecca Hahn, MD, also of Columbia University Medical Center/NewYork-Presbyterian. She cited the higher rate of renin-angiotensin-aldosterone system blocker use in that trial (84.7% vs 67.1% in COAPT) as an example.

It's not just that the trials are different in their continuum of disease -- they differ as well in the continuum of medical therapy, Hahn said, concluding that the two "may be much more concordant than previously thought."

"I continue to believe that COAPT and MITRA-FR provide complementary evidence as to which patients with heart failure and secondary MR are likely to benefit (and not benefit) by the MitraClip. Patients are likely to benefit if they have truly severe secondary MR without excessive LV [left ventricular] dilatation, and remain-symptomatic despite maximally tolerated guideline directed medical therapy," Stone similarly told 麻豆传媒.

MitraClip won FDA approval for the indication of secondary MR earlier this year, based on COAPT.

COAPT and MITRA-FR investigators are planning to pool patient-level data together for a meta-analysis. Each group is also continuing to follow patients out to 5 years.

Competing technologies that aim to replace the mitral valve entirely instead of just clipping it leave the patient with zero regurgitation and therefore may be expected to produce better results in future studies, Obadia suggested.

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