At four years of follow-up, patients with severe aortic stenosis at low risk for surgery undergoing transcatheter aortic valve implantation (TAVI) with a self-expanding valve had a 26% reduction in hazard for death or disabling stroke compared to those undergoing surgical aortic valve replacement (SAVR).
This was the latest finding from the Medtronic-funded EVOLUT Low Risk trial, presented during a late-breaking trial session at TCT 2023 (23–26 October, San Francisco, USA) by Michael J Reardon (Houston Methodist, Houston, USA) and published simultaneously in the Journal of the American College of Cardiology (JACC).
The Evolut Low Risk trial is a randomised, non-inferiority trial, in which TAVI with a self-expanding supra-annular bioprosthesis (CoreValve, Evolut R, or Evolut PRO; Medtronic) was compared with SAVR in patients who had severe aortic stenosis and were at low surgical risk. Patients enrolled in the trial are due to be followed out to ten years.
The four-year results of the trial follow on from the presentation of results out to three years at this year’s 2023 American College of Cardiology (ACC) annual scientific session (4–6 March, New Orleans, USA), in which investigators reported that TAVI resulted in “durable” benefits compared to surgery regarding all-cause mortality or disabling stroke in patients at low surgical risk.
From May 2016 to May 2019, 1,414 patients were randomised 1:1 to undergo TAVI (n=730) or SAVR (n=684). At four years, 94.7% of TAVR and 89.2% of SAVR patients were available for evaluation. The primary endpoint of all-cause mortality or disabling stroke at four years was 10.7% for TAVI vs. 14.1% for SAVR (hazard ratio [HR] 0.74, 95% confidence interval [CI] 0.54-1.00, p=0.05). In addition, the difference between the two groups for the primary endpoint continued to increase over time. At one year follow-up the difference between the two groups was 1.8% and at four years, the difference was 3.4%.
The results for the individual components of the primary endpoint were 9% compared to 12.1% (p=0.07) for all-cause mortality and 2.9% vs. 3.8% (p=0.32) for disabling stroke for TAVI vs. SAVR. The composite of all-cause mortality, disabling stroke, or aortic valve rehospitalisation was 18% with TAVI and 22.4% with SAVR (p=0.04). In addition, TAVI had significantly better haemodynamics (p<0.001 at all timepoints) as well as significantly less mean gradients greater than or equal to 20 mmHg (4% vs. 8.9%, p=0.002) or severe prosthesis-patient mismatch (1.1% vs. 3.5%, p=0.008).
“This longer-term data from the EVOLUT trial can help guide treatment decisions for low-risk patients with severe aortic stenosis,” said Reardon. “Not only did TAVI provide better initial outcomes compared to SAVR, but the benefit also continued to increase over time. Patients will be followed for 10 years to determine whether there is additional divergence of the clinical outcomes.”
