TAVR outperforms surgery through 4 years in low-risk patients with severe AS

Among low surgical-risk patients with severe aortic stenosis (AS), those who underwent transcatheter aortic valve replacement (TAVR) have better valve performance and clinical and haemodynamic outcomes up to 4 years compared with those who underwent surgical aortic valve replacement (SAVR), according to the EVOLUT Low Risk trial presented at TCT 2023.

“Variations of valve designs may lead to differences in valve performance, and we sought to determine if differences in valve performance led to differences in clinical outcomes,” said principal trial investigator Dr Michael Reardon from Methodist DeBakey Heart and Vascular Center in Houston, Texas, US.

A total of 1,414 patients (mean age 74 years) with severe AS were randomized in a 1:1 ratio to undergo either TAVR (n=730) or SAVR (n=684). TAVR was performed with the use of a self-expanding valve (Evolut R [73 percent], Evolut PRO [23.4 percent], or CoreValve [3.6 percent]).

At 4 years of follow-up, the primary composite endpoint of all-cause mortality or disabling stroke occurred in 10.7 percent of the patients in the TAVR group compared with 14.1 percent in the SAVR group, translating to a 26-percent reduction in the risk death or disabling stroke (hazard ratio [HR], 0.74; p=0.05).

The difference between the two groups in terms of the primary endpoint increased from 1.8 percent at 1 year to 3.4 percent at 4 years, indicating an increasing benefit of TAVR over time, Reardon noted.

When assessing individual components of the composite endpoint, TAVR was associated with lower rates of all-cause mortality (9.0 percent vs 12.1 percent; p=0.07) and disabling stroke (2.9 percent vs 3.8 percent; p=0.32) compared with SAVR. Its advantage at 4 years “is being driven by better all-cause mortality with the Evolut valve vs surgery,” said Reardon.

“[In terms of] stroke, we did not observe a late increase in stroke with Evolut vs surgery. This is probably related to the fact that Evolut is associated with a very low rate of clinical and subclinical valve thrombosis,” he noted.

The composite of all-cause mortality, disabling stroke, or aortic valve rehospitalization was lower with TAVR at 18 percent compared with SAVR at 22.4 percent (p=0.04).

Moreover, TAVR-treated patients had significantly better haemodynamics (p<0.001 at all timepoints) and significantly less mean gradients ≥20 mm Hg (4.0 percent vs 8.9 percent; p=0.002) and severe patient-prosthesis mismatch (1.1 percent vs 3.5 percent; p=0.008) through 4 years than the SAVR-treated patients.

“This longer-term data from the EVOLUT trial can help guide treatment decisions for low-risk patients with severe AS,” said Reardon. “Not only did TAVR provide better initial outcomes compared to SAVR, but the benefit also continued to increase over time.”

“In low-risk patients, the Evolut platform is a good first choice due to valve performance and associated excellent clinical outcomes,” he concluded.