Allegra TAVR System Feasible for Treating Degenerated Surgical Valves

PARIS, France—A transcatheter heart valve used to treat failing surgical bioprosthetic valves successfully improved measures of invasive and echocardiographic hemodynamics in a small feasibility study. The results were presented last week at EuroPCR 2019.

The Allegra valve (New Valve Technology) was successfully deployed in 29 of 30 elderly patients and there was no signal of early harm among those treated with the new technology, although one patient was converted to valve-in-valve TAVR with Evolut R (Medtronic) after device migration into the ascending aorta, reported investigators.

Presenting the VIVALL results during a hotline session, lead investigator Ulrich Schāfer (University Medical Center, Hamburg, Germany), said the self-expanding valve performed particularly well in this patient population, a group with very small internal diameters. “If you look at the design of the valve, you can imagine that it might be particularly suitable for valve-in-valve implantation,” he said. “It has a tubular-stent shape with a small belly. It’s a three-leaflet, pericardial tissue valve with a supra-annular design, which allows for easy positioning during the implantation.”

He added that there are more than 200,000 surgical aortic valve replacements performed each year and said these bioprosthetic valves typically break down after 10 or 20 years, depending on the valve type.

Degenerated Surgical Valves With Small Diameters

The VIVALL investigators included 30 symptomatic patients with a degenerated aortic bioprosthesis, which was defined as a mean aortic gradient greater than 40 mm Hg (or peak jet velocity greater than 4.0 m/s) and an aortic valve area less than 1.0 cm2. Symptomatic patients with severe bioprosthetic valve insufficiency were also included in the trial. The average age of patients was 78.6 years, and all were considered high risk for a redo surgical valve procedure.

Speaking during the session, Schāfer said VIVALL was quite an ambitious feasibility study given that 80% of the surgical valve patients had a bioprosthetic internal diameter of 21 mm or less and nearly one-quarter had an inner diameter of 19 mm or smaller. “Quite difficult bioprostheses,” he said. Additionally, roughly 50% of patients had previously received a Mitroflow (Sorin Group) or Mosaic (Medtronic) prosthetic valve, and these valves are known to have very small inner diameters, said Schāfer.

The transcatheter valve was successfully deployed in all but one person. The majority of patients received the 23-mm Allegra device. In terms of the echocardiographic findings, the mean pressure gradient decreased from 30.75 mm Hg at baseline to 14.75 mm Hg at 30 days and this improvement was observed across the range of inner diameters. There was also a significant improvement in functional capacity, with 71.4% of patients reporting NYHA class I/II symptoms at 30 days (compared with 80% of patients who had NYHA class III/IV heart failure at baseline). There were no incidents of paravalvular regurgitation and no pacemakers implanted.  

There were also no deaths, MI, strokes, or major bleeds at 30 days, but there was one case of suspected valve thrombosis treated with oral anticoagulation.   

Olaf Wendler, MD, PhD (King’s College Hospital, London, England), a panel member during the hotline session, was struck by the small inner diameters of valves treated with the new technology and said the valve performed well in reducing the mean pressure gradient. From a practical standpoint, however, Wendler wasn’t quite sure what to make of a transcatheter heart valve dedicated to patients with degenerated surgical bioprostheses. The Sapien 3 valve (Edwards Lifesciences) and CoreValve Evolut R, for example, have been used for several years for valve-in-valve procedures, he said.

“I couldn’t really see the advantage of the new valve, to be honest,” Wendler told TCTMD. “In terms of its function, it was fine. I was surprised that a company is focusing purely on designing a device for valve-in-valve treatment. It’s a relatively small number of patients who come with this type of problem, and you need to have a critical number [of cases] to make it viable from an economic point of view.”

The Allegra device is currently approved in Europe for the treatment of severe calcified aortic valve stenosis in patients at high risk for surgery. Wendler pointed out that the device is relatively long—the frame height ranges from 37.3 to 43.0 mm—which might make it difficult to perform future coronary interventions, particularly if it’s used in younger TAVR patients who go on to develop more significant coronary artery disease after device implantation.

Photo Credit: New Valve Technology