SMART Analysis Compares Hemodynamic Performance of Self-Expanding and Balloon-Expandable TAVR Devices

May 3, 2024—An analysis from the SMART trial demonstrated clinical noninferiority of self-expanding versus balloon-expandable valves in patients with aortic stenosis (AS) and small aortic annuli (SAA) undergoing transcatheter aortic valve replacement (TAVR). The analysis also confirmed superiority of the performance of self-expanding valves over time based on hemodynamics, and data showed similar positive results in patients aged < and ≥ 80 years.

The SMART trial is an international, prospective, multicenter, randomized (1:1) postmarket trial comparing the safety and performance of the self-expanding Evolut Pro/Pro+/FX valves (Medtronic) versus the balloon-expandable Sapien 3/3 Ultra valves (Edwards Lifesciences) in TAVR patients with symptomatic severe AS and SAA.

The late-breaking results from the SMART analysis were presented at SCAI 2024, the Society for Cardiovascular Angiography & Interventions scientific sessions held May 2-4 in Long Beach, California.

The SCAI press release noted that patients with AS and SAA, who are typically female and underrepresented in clinical trials, are at risk for impaired valvular hemodynamics and associated adverse cardiovascular outcomes after TAVR. The underrepresentation of women in research and the severity of the condition creates a call for more clinical data.

Eligible patients in the SMART trial had an aortic valve annulus area ≤ 430 mm² by CT and suitable anatomy for transfemoral TAVR with either an Evolut Pro/Pro+/FX or a Sapien 3/3 Ultra valve. The coprimary endpoints were (1) a clinical outcome composite of mortality, disabling stroke, or heart failure rehospitalization and (2) a valve function composite of bioprosthetic valve dysfunction (BVD) through 12 months.

As summarized in the SCAI press release, the SMART trial was composed of a total of 716 patients (87% women; mean age, 80 years) treated at 83 sites and met both primary endpoints. Compared with the balloon-expandable valves, the supra-annular self-expanding valves demonstrated noninferior clinical outcomes and superior valve performance as measured by multiple definitions of BVD as well as by standard hemodynamics (doppler velocity index, effective orifice area, severe prosthesis‐patient mismatch, and mean gradient > 20 mm Hg) at 1 year.

As an additional analysis, the hemodynamics over time were evaluated and found to be similar between cohorts at baseline and favored self-expanding valves compared to balloon-expandable valves at all follow-up time points through 12 months (P < .001). The results were also consistent in patients aged < or ≥ 80 years. The balloon-expandable valves had a BVD difference of 39.8% for patients < 80 years old and 27.1% for patients ≥ 80 years old (both P < .001).

Howard C. Herrmann, MD, John W. Bryfogle Professor of Cardiovascular Medicine and Surgery, Health System Director and Section Chief of Interventional Cardiology, Perelman School of Medicine at the University of Pennsylvania in Philadelphia, serves as lead investigator of the study.

“The SMART trial is the largest, most rigorous trial to date to randomize patients using the two most widely used TAVR devices, and the largest TAVR trial to enroll mostly women,” commented Dr. Herrmann in the SCAI press release. “We are excited to reiterate our previously presented findings in front of the interventional cardiologist community with our additional analysis.”

Dr. Herrmann continued, “This confirms the hemodynamic superiority of self-expanding supra-annular valves, which allow for greater options and improved decision-making for clinicians. It was also beneficial to see that this treatment option produced similar positive results for the more active younger patient population.”

Longer-term follow-up of the SMART trial is ongoing, advised the SCAI press release.

In April 2024, the 1-year results from SMART were presented at ACC.24, the American College of Cardiology’s annual scientific session in Atlanta, Georgia, and simultaneously published online by Dr. Herrmann et al in The New England Journal of Medicine.