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NEW ORLEANS -- Transcatheter repair of functional mitral regurgitation (or secondary MR) with MitraClip improved quality of life and hemodynamics better than optimal medical therapy alone, COAPT trial analyses showed.

Health status remained substantially impaired on maximally-tolerated medication, with just a 2.1-point gain over the baseline 52.4 on the 100-point Kansas City Cardiomyopathy Questionnaire (KCCQ) overall summary scale. But scores improved by a clinically-meaningful 16.9 points at 1 month after the transcatheter procedure.

Advantage with MitraClip fell only slightly to 14.5 points at 12 months and 12.8 points at 24 months (all P<0.001 between groups), reported Suzanne Arnold, MD, of Saint Luke's Mid America Heart Institute in Kansas City, Missouri, at the American College of Cardiology (ACC) meeting. The findings were simultaneously published online in the .

Quality of life gained the most from MitraClip, but all the other KCCQ domains improved significantly as well. Bayesian analysis to account for bias from differential mortality between groups likewise came out with a significant 18.9 point advantage to clipping. Generic health status measured on the Short Form 36 (SF-36) also favored intervention across time points.

The proportion of patients alive with a "moderately large," ≥10-point KCCQ score improvement, was 36.4% with MitraClip versus 16.6% with medication alone (P<0.001) at 24 months, for a number needed to treat of 5.1.

Previously reported primary results from the COAPT trial showed a significant reduction in both heart failure hospitalization and all-cause mortality at 24 months for MitraClip, which led to FDA approval for secondary mitral regurgitation on Thursday.

"I think these findings are as important if not more important than the primary endpoint, because from the patient perspective ... most patients don't necessarily want to live longer unless they are going to feel better and they are going to have a decent quality of life," said ACC discussion panelist Mayra Guerrero, MD, of the Mayo Clinic in Rochester, Minnesota.

Mary Norine Walsh, MD, of St. Vincent Heart Center in Indianapolis and immediate past president of the ACC, agreed that the findings add to the positive news on MitraClip.

"On all fronts, all the endpoints were met, so it's just further evidence of benefit in the select patient population," she said. "It would be pretty surprising if the other outcomes were what they were and the quality of life didn't improve. It's very robust data."

However, Walsh reiterated the cautious note sounded when the initial findings came out: patient selection and optimization of medical and implantable device therapy by a heart failure specialist as done in the trial will be key to achieving these results.

"In the wake of the FDA approving this, I think echocardiographers at valve centers need to be aware and look at echos in the same way, and make sure they're going to use this in patients who parallel the patients who showed benefit. Otherwise we can have indication creep... and you're going to have people with any kind of MR getting a clip before they are fully titrated on ACE, beta-blocker, ARNI [angiotensin receptor-neprilysin inhibitor], whatever. It's a great therapy for the right patients."

A second presentation at the same late-breaking clinical trial session reported that left ventricular end systolic and end diastolic volumes and MR severity improvements were significantly better at 24 months with clipping than among controls.

All subgroups showed benefit across degree of left ventricular dysfunction and dimensions, pulmonary hypertension, and severity of tricuspid valve dysfunction, reported Federico Asch, MD, of MedStar Health Research Institute in Washington.

The only predictor of poor outcomes after MitraClip was right ventricular systolic pressure.

COAPT included 614 symptomatic heart failure patients with grade 3-4+ secondary MR, an effective regurgitant orifice of 31 mm², and rigorous assurance that patients really had maxed out what optimal medical therapy and implantable cardiac device therapy could do before randomization. Patients were randomized to MitraClip atop medical therapy or medical therapy alone.

While patients were not blinded to treatment assignment in COAPT, the effects were unlikely to represent placebo effects, Arnold's group suggested, "[g]iven the magnitude of sustained health status benefit and the concordance of the results with other less subjective outcomes (including death and rehospitalization)."