Self-expanding versus balloon-expendable TAVR in patients with small aortic annuli

The SMART study compared the 2 most widely used transcatheter aortic valve replacement (TAVR) devices in patients with severe aortic stenosis and small annuli and found non-inferiority between the supra-annular self-expanding (SEV) and the intra-annular balloon-expandable valve (BEV). However, regarding bioprosthetic valve dysfunction (BVD) in these patients, SEV was superior at 1 year.

Besides influencing long-term results, haemodynamic differences in valve performance can be influential in up to 40% of patients, typically women with small aortic annuli [1,2]. “It’s important to study women separately because they present differently and are at greater risk for complications after both surgery and TAVR,” Prof. Howard Herrmann (Perelman School of Medicine, PA, USA) further explained [1].

Hence, the SMART trial (NCT04722250), conducted at 83 sites across Europe, North America, and the Middle East, set out to compare the Evolut SEV with the BEV SAPIEN platform for TAVR in this cohort of patients with small aortic annulus. The first co-primary endpoint, a clinical outcome composite of mortality, disabling stroke, and heart failure re-hospitalisation through 12 months, tested for non-inferiority between the devices. The second endpoint assessed BVD for superiority within the implanted population.

As can be expected per design, about 87% of the over 700 included participants were women. The mean baseline age was about 80 years and the mean STS-Predicted Risk of Mortality (PROM) score for operative risk was 3.3% (SEV) and 3.2% (BEV). At 1 year, the clinical outcome endpoint was met with 10.6% in the BEV and 9.4% in the SEV arm (P_{non-inferiority}<0.001. The valve dysfunction endpoint, in contrast, found rates of 41.6% for BEV and 9.4% for SEV through 12 months, demonstrating significant superiority of BEV (P<0.001).

Secondary endpoints included differences in mean gradient, effective orifice area, haemodynamic structural valve dysfunction, BVD in women, and moderate/severe prosthesis patient mismatch. “All five of these secondary endpoints were superior for the SEV at a P-value of less than 0.001,” underlined Prof. Herrmann.

Regarding safety outcomes, new pacemaker implants were numerically higher in the SEV group at 1 and 12 months, while prosthetic valve endocarditis after 1 year was higher in the BEV arm. Otherwise, the major safety endpoints were deemed similar between the groups.

“Based on these large differences that we observed in valve performance, we expect that the SEV will demonstrate improved valve durability and outcomes during longer-term follow-up,” Prof. Herrmann concluded.

1. Herrmann HC, et al. Self-expanding versus balloon-expandable transcatheter aortic valve replacement in patients with small aortic annuli: primary outcomes from the randomised SMART trial. LB3, Session 406, ACC 2024 Scientific Session, 6–8 April, Atlanta, USA.
2. Playford D, et al. J Am Soc Echocardiogr. 2020;33(9):1077-86.

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Posted on 16 May 202413 June 2024