PARIS – The investigational mechanically expandable Lotus valve system for transcatheter aortic valve replacement proved significantly more effective than the commercially available CoreValve platform in patients with severe aortic stenosis deemed at high or extreme surgical risk in the randomized pivotal phase III REPRISE III trial, Ted E. Feldman, MD, reported at the annual congress of the European Association of Percutaneous Cardiovascular Interventions.
The 1-year composite primary effectiveness endpoint comprised of all-cause mortality, disabling stroke, and moderate or greater paravalvular leak (PVL) occurred in 17% of patients randomized to the Lotus transcatheter aortic valve replacement (TAVR) device, compared with 29% of those in the CoreValve group, said Dr. Feldman, director of the cardiac catheterization laboratory at NorthShore University HealthSystem in Evanston, Ill.
Bruce Jancin/Frontline Medical News
Dr. Ted E. Feldman
A key finding was that the Lotus valve group had a 1-year rate of moderate or greater PVL of just 2% as assessed in a central core lab, compared with an 11% rate in patients randomized to the classic CoreValve or the subsequent-generation Evolut R device, he observed.
“With the Lotus valve there was no or only trace PVL in over 85% of patients. This is probably even more important than the low rate of moderate or severe PVL. The valve really does result in virtually no PVL in the vast majority of patients. That’s unique to this platform,” the cardiologist said in an interview.
The unprecedented low rate of moderate or severe PVL at 1 year postprocedure is attributable to the polymer seal delivered via the Lotus system for that express purpose, he explained.
REPRISE III was the first large randomized comparative clinical trial featuring two TAVR valves, an event that reflects the rapid expansion of the field. All previous major trials had compared TAVR with surgical aortic valve replacement.
REPRISE III randomized 912 TAVR patients at 55 centers 2:1 to the Lotus valve in its 23-, 25-, or 27-mm configurations or to a CoreValve at 26, 29, or 31 mm. Roughly half of the CoreValve group got the newer repositionable and retrievable Evolut R valve, while the earlier enrollees received the nonrepositionable classic CoreValve.
The Lotus valve group proved noninferior to the CoreValve recipients for the primary safety endpoint, a 30-day composite of all-cause mortality, stroke, major or life-threatening bleeding, major vascular complications, and stage 2 or 3 acute kidney injury. The rates were 20.3% in the Lotus arm and 17.2% with CoreValve.
The 1-year rate of disabling stroke was 3.6% in the Lotus group versus 7.3% in the CoreValve group. Dr. Feldman downplayed the importance of this difference, even though it was statistically significant. The Lotus valve performed as expected, but the disabling stroke rate in the CoreValve group was higher than in earlier studies for reasons unknown, most likely simply the play of chance, he said.
“I think the real message here is that the Lotus valve performed very well,” the cardiologist said. “There have been concerns that repositioning the valve into a better position during the deployment process might create excess stroke. It appears clear that’s not the case.”
The ability to reposition the Lotus device resulted in a significantly lower rate of repeat procedures at 1 year: 0.2% versus 2% with the CoreValve, as well as zero cases of aortic valve malposition and valve-in-valve deployment.
The need for a new pacemaker within 30 days after TAVR was strikingly more common in the Lotus valve group: 36%, compared with 20% with the CoreValve. Dr. Feldman attributed the high new pacemaker rate in the Lotus arm partly to the operators’ limited experience with the novel valve along with the fact that REPRISE III used a first-iteration device deployment mechanism. An improved deployment mechanism designed to minimize problematic contact with the left ventricular outflow tract was developed too late for inclusion in the trial. But in a recent European study using this proprietary deployment system, known as Depth Guard, the new pacemaker rate was below 20%.
The learning curve for the new Lotus valve system is “not at all challenging,” according to the cardiologist. He noted that U.S. operators participating in REPRISE III, who had no prior experience with the device, were allowed only two initial cases in order to gain experience; after that, every patient counted in the clinical trial results.
The REPRISE III results will be offered to the Food and Drug Administration to support regulatory approval of the device in high-surgical-risk patients. Dr. Feldman said Boston Scientific plans to conduct an additional clinical trial of the Lotus valve, this time in intermediate-risk patients, with the goal of gaining an expanded indication. This, too, will be a head-to-head comparison with a commercially available TAVR valve, probably the Edwards Sapien 3 valve.
REPRISE III was sponsored by Boston Scientific. Dr. Feldman reported serving as a consultant to that company, Abbott, and Edwards Lifesciences, and having received institutional research grants from those companies as well.