麻豆传媒

BELGRADE, Serbia -- A novel percutaneous device for mitral valve regurgitation helps get failing hearts back in shape and eases symptoms, early-phase results showed.

The device, which pushes the mitral valve leaflets closer together from inside the adjacent coronary sinus, reduced left ventricular systolic and diastolic volume at 12 months (both P=0.015), David G. Reuter, MD, PhD, of Seattle Children's Hospital and chief medical officer of device maker Cardiac Dimensions, and colleagues found.

In the 36 treated patients, 6-minute walk distance rose by more than 100 m (109 yards) by 1 year and even further by 2 years of follow-up, they reported here at the Heart Failure Congress and simultaneously online in the European Heart Journal.

That's an impressive benefit in exercise capacity, Reuter told 麻豆传媒. "Patients feel dramatically better," he said. "If you compare that to what drugs offer, it's off the charts."

The device, known as the Carillion Mitral Contour System, acts like the annuloplasty ring sewn around the mitral valve in some surgical approaches to mitral valve repair.

Another percutaneously implanted device, the MitraClip, holds together the mitral leaflets to divide the valve into two smaller openings.

Both tackle functional mitral regurgitation that is part of a "vicious cycle" with left ventricular dysfunction and remodeling. But functional mitral regurgitation hasn't been proven as a treatment target itself, noted study discussant Piotr Ponikowski, MD, PhD, of the Medical University and Clinical Military Hospital in Wroclaw, Poland.

The newly updated European heart failure (HF) guidelines call isolated mitral valve surgery for even severe functional regurgitation and severe systolic dysfunction patients who can't be revascularized questionable.

But the guideline authors suggested that percutaneous edge-to-edge repair may be considered for patients with an indication for valve repair, but who are inoperable or at unacceptably high risk.

The new device is promising but requires more experience, Ponikowski cautioned.

Technical issues and the relatively low 68% implantation rate among patients attempted raise questions that still need to be answered, he explained.

In the phase I TITAN study, only 36 patients of the 53 attempted actually received a permanent implant.

Reuter explained that his group took a conservative approach, placing the device but recapturing it if coronary artery flow appeared impeded by it (eight cases) or if the mitral regurgitation didn't drop by at least one full grade immediately (nine cases).

Now that safety has been shown, he said, the clinical implant rate is likely to go up to 80% to 90%.

Safety results in the total intent-to-treat population showed a 1.9% rate of 30-day major adverse events (one death in a patient not implanted due to contrast-induced renal failure).

That's lower than the 24% combined mortality and morbidity reported with surgical mitral repair at 30 days and the 15% 30-day major adverse event rate reported with MitraClip, the researchers pointed out.

The 12-month mortality rate reported in the paper was similar between implanted and attempt-only patients at 22% versus 24%.

The presentation reported additional follow-up results, bringing the 36-month rate of mortality to 30.6% in the implanted patients. Two had a myocardial infarction over the 36-month period (neither judged device related) for a total 33% major adverse event rate.

No patients had device embolization, cardiac perforation, or required surgery related to the device over 36 months of follow-up.

The device, made of nitinol, fractured in nine of the 36 cases. All remained functional and stayed in place without any related adverse events or clinical consequences.

A redesign to reduce stress on the metal at a key point should fix the problem, Reuter noted.

Echocardiography showed a roughly 40% drop in regurgitant volume with the procedure compared with the attempted but not implanted patients (P=0.005).

Left ventricular end diastolic and end systolic diameters decreased significantly with the device as well (P<0.001 and P=0.003, respectively).

The mean 19% reduction in left ventricular end systolic volume at 12 months (P=0.010) "is also important since previous studies show that a decrease in LV end-systolic volume of more than 10% following CRT [cardiac resynchronization therapy] is a strong predictor of lower long-term mortality and HF events," the group wrote.

The 6-minute walk distance rose from 302 m at baseline to 406 at 12 months for the implanted patients and to 450 at 24 months (P=0.014 and P=0.005).

NYHA class fell from an average 3.1 at baseline to 2.1 at 12 months and 24 months (P<0.001).

The study was limited by lack of a randomized and blinded comparator. "As such, a randomized trial comparing intervention with a medically managed control group is warranted," Reuter and colleagues concluded.

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