Three-year results from the Evolut Low Risk trial have shown “durable” benefits of transcatheter aortic valve implantation (TAVI) compared to surgery regarding all-cause mortality or disabling stroke in patients at low surgical risk.
This is according to the latest findings from the trial, presented in a late-breaking trial session at the 2023 American College of Cardiology (ACC) annual scientific session (4–6 March, New Orleans, USA) by John Forrest (Yale School of Medicine, New Haven, 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, comparing TAVI with a self-expanding supra-annular bioprosthetic valve (CoreValve, Evolut R, or Evolut PRO; Medtronic) with surgical aortic-valve replacement (SAVR) in patients with severe aortic stenosis at low surgical risk. Patients enrolled in the trial are due to be followed out to ten years.
The analysis presented by Forrest at ACC included 1,468 patients enrolled across centres in Australia, Canada, France, Japan, The Netherlands, New Zealand and USA, of whom the median age was 74 years and 35% were women. All had severe symptomatic aortic stenosis and were deemed to be at low risk from surgery, defined as having no more than a predicted 3% risk of death within 30 days of the procedure. Patients were randomly assigned to receive TAVI or SAVR.
Two-year results from the trial, presented at the virtual EuroPCR meeting in 2021, signalled that the primary outcome of death or disabling stroke occurred in 4.3% of patients in the TAVI arm vs. 6.3% in the surgical group, with commentators offering the view that the findings offer “reassuring” evidence on the outcomes of TAVI in low risk patients
In the current study, after all patients had been followed for at least three years, 7.4% of those treated with TAVI had died or experienced a disabling stroke, compared with 10.4% of those treated with SAVR, a difference that fell just short of statistical significance (hazard ratio [HR] 0.70; 95% confidence interval [CI] 0.49 to 1; log-rank p=0.051).
Occurrence of the secondary combined endpoint of all-cause mortality, disabling stroke, or aortic valve rehospitalisation was significantly lower in the TAVI group (13.2%) than the SAVR group (16.8%; HR 0.76; 95% CI 0.58 to 1; p=0.050).
Mild paravalvular regurgitation was more frequent in the TAVI group (20.3% vs. 2.5%), but at three years, there was no significant difference in the presence of moderate or greater paravalvular regurgitation (0.9% TAVI vs. 0.2% surgery; difference, 0.7%; 95% CI 0.2% to 1.6%).
“This study shows that the initial benefit of TAVI remained broadly consistent over the first three years,” said Forrest, the lead author of the study. “In patients who are at low risk for death, stroke or other serious complications of aortic valve surgery, we need to have compelling evidence that TAVI is both safe and effective and also that the results are durable. The consistent benefit of TAVI at three years is not something that has been observed in prior studies and provides further evidence that TAVI deserves to be the dominant treatment modality for patients with aortic stenosis undergoing valve replacement.”
While the current study’s findings are largely considered by investigators to provide reassuring evidence for the benefit of TAVI in low risk patients, Forrest said that longer-term data for low-risk patients are still needed and patients enrolled in the study will be followed for 10 years.
“Patients with severe aortic stenosis who are at low surgical risk should continue to engage in shared decision-making with their physicians concerning the risks and benefits of surgical versus transcatheter valve replacement,” Forrest said.