SMART Compares Evolut and Sapien TAVR Devices in Patients With Small Valve Annuli

April 7, 2024—The American College of Cardiology (ACC) announced that findings from the SMART trial demonstrated that patients with a small aortic annulus who underwent transcatheter aortic valve replacement (TAVR) with a supra-annular self-expanding valve had similar clinical outcomes and superior valve performance at 1 year compared with patients who underwent TAVR with a balloon-expandable valve.

The trial, funded by Medtronic, is the first randomized head-to-head comparison of the supra-annular self-expanding Evolut Pro/Pro+/FX (Medtronic) and the balloon-expandable Sapien 3/3 Ultra (Edwards Lifesciences), which are the two most widely used TAVR devices.

The ACC noted that SMART is also the first trial to focus specifically on informing device selection for patients with small aortic annuli, a patient group that is primarily women and has been underrepresented in previous clinical trials for TAVR.

The SMART results were presented at the ACC.24 Annual Scientific Session held April 6-8 in Atlanta, Georgia, and simultaneously published online by Howard C. Herrmann, MD, et al in The New England Journal of Medicine.

“We think it’s important to study this population, which represents up to 40% of all patients getting TAVR, and it’s important to study women, who make up the majority of the small annulus population,” commented Dr. Herrmann in the ACC press release. MD, “There was a huge difference—32.2 percentage points—in 1-year bioprosthetic valve dysfunction favoring the Evolut platform. The magnitude of the hemodynamics difference was larger than we expected.”

As summarized in the ACC press release, the trial enrolled 716 patients who underwent TAVR at 83 international sites in North America, Europe, and the Middle East. Patients had a valve annulus of ≤ 430 mm² and anatomy suitable for either the Evolut Pro/Pro+/FX or the Sapien 3/3 Ultra. In the study, 87% of study patients were women. Patients were considered to face a low to intermediate risk of serious cardiac events in a baseline risk assessment.

Half of the patients were randomly assigned to receive the self-expanding Evolut valve, which is constructed using porcine tissue and materials that allow the valve to expand to full size when it reaches body temperature. The other half of patients received the balloon-expandable Sapien valve, which is made from bovine tissue and inserted inside the heart valve by using a balloon to expand to full size.

The ACC press release reported that at 1 year, the trial met both primary endpoints. Investigators found no significant difference between groups in terms of a composite of death, disabling stroke, or rehospitalization for heart failure (9.4% with Evolut vs 10.6% with Sapien).

The Evolut valve was found superior in terms of valve function, defined in terms of a composite of structural and nonstructural valve deterioration, blood clotting around the valve, infection of the valve, and aortic valve reintervention. This composite valve function endpoint was 9.4% of Evolut patients and 41.6% of Sapien patients.

All prespecified secondary endpoints were statistically significant in favor of the self-expanding valve, including blood pressure across the valve and size of the valve opening.

According to the ACC press release, Dr. Herrmann said that the supra-annular design of the self-expanding valve likely accounts for the superior hemodynamics observed in the study because it allowed for implantation of valves with a larger opening than the balloon-expandable platform.

Additionally, the investigators stated that the results are reassuring in terms of clinical outcomes of both valve types and noted that further follow-up could help shed light on how the two devices perform in this patient population in the long term when the difference in valve function may affect how long the valve lasts. Investigators will continue to track outcomes during the next 5 years.

“The fact that we had similar clinical outcomes at 1 year is an important finding because a lot of people think one valve is better than the other, and here in a randomized trial, at least at 1 year in a subset of patients, the clinical differences weren’t different,” Dr. Herrmann said. “The trial gives us a ton of information. Clinically, at 1 year, either valve is reasonable, and the results are pretty similar, although mild valve leaks and some measures of quality of life were better with Evolut. Furthermore, this is the first time we get to identify differences between the devices that might impact later patient outcomes.”

Dr. Herrmann is the John W. Bryfogle Professor of Cardiovascular Medicine at the Perelman School of Medicine at the University of Pennsylvania and Section Chief for Interventional Cardiology at the Hospital of the University of Pennsylvania in Philadelphia.

Finally, the ACC press release reported that similar results were seen across all subgroups; however, the investigators plan to analyze additional subgroups to determine whether valve performance or clinical outcomes may vary among people in different age groups or among people with different comorbidities or annulus size.

The investigators also plan to assess measures of valve durability over time, which Dr. Herrmann said is becoming more important as younger patients are increasingly undergoing TAVR.