Transcatheter Aortic Valve Replacement with a Repositionable Supra-annular, Self-expanding, Bioprosthesis in Patients with Severe Aortic Stenosis Suboptimal for Surgery: 3-Year Results from the Evolut R US Pivotal Trial

Background
Evolut R is a supra-annular, porcine pericardial, self-expanding transcatheter aortic valve (TAV) with a low (14F equivalent) profile delivery system, conformable annular sealing, which can be partially or completely repositioned during TAV deployment. Longer-term follow-up with new valves is lacking.

Methods
Patients with severe aortic stenosis considered to be at least high risk for surgery were treated with the Evolut R TAV at 23 clinical sites in the United States. An independent Clinical Events Committee adjudicated all adverse events. An independent echocardiography core laboratory (Mayo Clinic, Rochester, MN) assessed valve hemodynamics. Follow-up is planned through 5 years.

Results
A total of 237 of 241patients with attempted implants received a 23, 26, or 29 mm Evolut R TAV between August 2014 and June 2015. Baseline mean age was 83.3±7.2 years, 68.5% were women, STS was 7.4±3.4% and 83.0% had New York Heart Association class III/IV symptoms. In this primarily high-risk study cohort, the 3-year all-cause mortality rate was 25.0%, cardiovascular mortality was 15.6%, disabling stroke was 6.1% and the permanent pacemaker implantation rate was 21.2%. A spontaneous myocardial infarction occurred in 5 patients (2.5%). There were no cases of valve thrombosis or other valve-related dysfunction requiring repeat procedure to 3 years. The mean effective orifice area and AV gradient were 1.9 ± 0.6 cm² and 8.3 ± 4.3 mm Hg at 3 years. PVL was absent or trace in 79.2%; mild in 20.0%, moderate in 0.8%, and no patients had severe at 3 years. Most patients (92.1%) had NYHA class I or II symptoms (86.4% had improved symptoms vs baseline); and the mean KCCQ overall summary score was 69.7 at 3 years.

Conclusions
The Evolut-R self-expanding transcatheter aortic valve was safe and effective for the treatment of severe aortic stenosis at 3 years post-procedure.