In patients with severe stenosis in a small aortic annulus (≤ 430 mm²), more than 85% women, should the Evolut self-expanding supra-annular valve (Medtronic) or the SAPIEN balloon-expandable intra-annular valve (Edwards) be preferred for transcatheter aortic valve implantation (TAVI)? The 3-year results of Small Annuli Randomized to Evolut (SMART trial), which compared the two strategies in this population, were presented at EuroPCR2026.

They show that the hemodynamic benefits observed at 1 year with the self-expanding valve persist at 3 years. Compared with the balloon-expandable valve, hemodynamic performance remains superior and the risk for valve dysfunction is lower. However, these benefits have not yet translated into a reduction in major clinical events.

Nevertheless, “these results should influence valve selection in patients with a small aortic annulus. Everyone agrees that poor hemodynamic performance has adverse consequences” stated Howard C. Herrmann , MD, University of Pennsylvania, Philadelphia, during a press conference.

A Future Impact on Clinical Events?

The consequences of TAVI with less favorable hemodynamic parameters generally result in an increase in clinical events starting at 3 years, he explained. Compared to patients receiving a prosthesis with better hemodynamic outcomes, the mortality curve begins to diverge after 3 years. We should therefore see a clinical difference within the next 2 years.

We must now await the results of the planned 5-year follow-up for this trial to confirm an effect on the primary endpoint, which is the primary composite endpoint of all-cause mortality, disabling stroke, or rehospitalization for heart failure.

When asked to comment on the results following the presentation, Anna Petronio , cardiologist, University of Pisa, Pisa, Italy, noted that the latest generation of balloon-expandable valves was not included in the study.

“We now have a fifth generation of balloon-expandable valves. It has a larger valve surface area and a lower aortic gradient than previous models. Would the results be different with these new-generation valves?” the cardiologist wondered.

More Than 85% of Participants Were Women

Most women have a smaller-than-average aortic annulus. However, it is known that a small annulus is associated with an increased risk for hemodynamic adverse effects following TAVI implantation. Several studies have shown that self-expanding valves have better hemodynamic outcomes than balloon-expandable valves, thanks to their supra-annular expansion.

The international, multicenter SMART trial was designed to assess and compare the performance of these two valves in this patient population. It enrolled 716 patients with severe symptomatic aortic stenosis and a small annulus — defined on CT before TAVI as an area of ≤ 430 mm² — including a mean age of about 80 years, more than 85% women, mean Society of Thoracic Surgeons Predicted Risk for Mortality was 3.3%.

Patients were included regardless of surgical risk. They were randomized to receive, via a percutaneous approach, either a self-expanding Evolut valve (PRO, PRO+, or FX) or SAPIEN 3/3 Ultra valve.

In addition to the composite endpoint for major clinical events, the primary endpoints included hemodynamic structural valve dysfunction (mean gradient ≥ 20 mm Hg), nonstructural valve dysfunction (severe prothesis-patient mismatch (PPM) or ≥ moderate aortic regurgitation), clinical thrombosis, endocarditis, and aortic valve reintervention.

After 3 years, there was no significant difference between the self-expanding and balloon-expandable groups in the composite outcome of mortality, disabling stroke, and rehospitalization for heart failure, which occurred in 25.4% and 22.6% of patients, respectively. Likewise, none of the individual components of the primary endpoint showed a significant difference when evaluated on their own.

PPM

In contrast, the rate of bioprosthetic dysfunction at 3 years was significantly lower in the self-expanding group than in the balloon-expandable group (16.3% vs 54.4%). This difference was primarily due to lower rates of structural dysfunction (6.7% vs 46.4%) and nonstructural dysfunction (7.7% vs 20.4%).

Compared with balloon-expandable valves, self-expandable valves had a larger valve area, a lower mean aortic gradient, and a higher Doppler velocity index. The rate of moderate-to-severe PPM, as defined by the latest VARC-3 classification, was also significantly lower in the self-expanding group (10.3% vs 35.1%).

After adjusting for several variables, the presence of moderate-to-severe PPM was associated, across the entire cohort, with a more than doubled risk for cardiovascular death (hazard ratio [HR], 2.24; 95% CI, 1.18-4.25; P = .032). This association appears even more pronounced in patients receiving a balloon-expandable valve, with a nearly threefold increased risk for cardiovascular mortality (HR, 2.98; 95% CI, 1.20-7.38).

“All hemodynamic parameters — both individual and composite — remained superior with Evolut, particularly due to a significantly lower risk of PPM,” commented Herrmann. “The results underscore the importance of minimizing PPM as much as possible,” he concluded.

Herrmann disclosed financial relationships with Abbott, Edwards Lifesciences, J&J, Medtronic, Carvolix, and Microinterventional Devices.

This story was translated from Medscape’s French edition.