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Self-expanding TAVR system approved in larger size
Medtronic announced that the FDA approved its self-expanding transcatheter aortic valve system in a new size, the largest currently available in the United States.
The system (CoreValve Evolut R) is now available with a 34 mm valve, indicated for patients with severe aortic stenosis at high or extreme risk for surgery with an annulus size of 26 mm to 30 mm, according to a press release issued by the company.
Patients who require such a large valve are estimated to comprise 25% to 30% of the eligible TAVR population worldwide, but many were unable to undergo TAVR previously because of the size of their affected valve, the company stated in the release.
The valve is delivered via a catheter system (EnVeo) with an in-line sheath, and the system has a delivery profile equivalent to 16F, according to the release.
Perspective
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This is a big step forward for patients and physicians that will allow us to effectively treat very large annular diameters that may not have been effectively treated with the current technology.
We’ve learned from early and midterm experience with CoreValve that up to 30% of patients have an aortic annular diameter of more than 26 mm. That’s a very large number of patients, yet we were still limited in some patients by the restriction of an upper limit of 29 mm annular diameter for the CoreValve 31 mm device. When we were relatively undersizing those larger diameters, we were plagued with some patients who had important degrees of paravalvular regurgitation.
The real advance with the Evolut R 34 mm valve is that we can effectively treat patients with annular diameters from 26 mm up to 30 mm, which likely includes 98% to 99% of all available patients, with the exception of some patients with bicuspid aortic valves with very large aortic annulae. So this is a significant step. Even more importantly, the construct of the Evolut R 34 mm valve allows us to have a repositionable and retrievable device to optimize positioning. We had such a good experience with the device in clinical trials because we could more accurately position it. Many of the advantages of the Evolut system, including conformational changes at the inflow that allow there to be a more controlled and self-centering deployment, have been a real advantage, and that now has been expanded to the larger annular sizes. Treating those sizes with the previous generation of CoreValve presented some challenges in positioning due to the mechanical force of the valve. The Evolut 34 mm valve behaves like the Evolut family series, and there’s much more predictable positioning.
Another advantage is that if the positioning is not optimal or if there is any outward mobility of the valve, it can be retrieved and recaptured, and then repositioned in a more appropriate place. The challenges we had with the 31-mm previous-generation valve are going to be largely mitigated by the better controllability of the deployment and the recapturability in the setting where the initial deployment is not where one wants to be.
We would like to see this serve as a platform for the next generation of devices, the Evolut Pro, which have a very thin pericardial membrane on the outer edge of the inflow tract, which will be a much-needed addition to reduce the degree of paravalvular regurgitation.