ACC.24 – In the SMART trial which enrolled mostly women, the 1-year efficacy and safety of the supra-annular, self-expanding Evolut valve was compared with the intra-annular balloon-expandable SAPIEN valve in patients with severe aortic stenosis and small aortic valve annulus.

This summary is based on the presentation of Howard Herrmann, MD (Philadelphia, PA, US) at the ACC.24 Scientific Session – Self-Expanding Versus Balloon-Expandable TAVR in Patients with Aortic Stenosis and Small Aortic Annuli – Primary Outcomes from the Randomized SMART Trial

Introduction and methods

Previous studies demonstrated that the supra-annular self-expanding Evolut valve has superior hemodynamic properties compared with the intra-annular balloon-expandable SAPIEN platform. Moreover, hemodynamic valve performance is associated with long-term outcomes. These hemodynamic improvements may be in particular important in patients with a small aortic annulus who makes up to 40% of patients, mostly women. Women with aortic stenosis present differently than men and are at increased risk of complications after TAVR surgery.

The supra-annular Evolut valve is made of porcine material and has a nitionol frame. The intra-annular SAPIEN has a Cobalt-chromium frame with bovine leaflets. With the supra-annular valve one can get a larger valve in the annulus than with the SAPIEN valve, which may explain the benefit in hemodynamic properties with the Evolut valve. Moreover, the struts that hold the leaflets are at the outside of the cage for the Evolut valve, whereas for the SAPIEN valve they are at the inside, and as a results there is less room for the leaflets to open.

The SMART (Small Annuli Randomized to Evolut or SAPIEN) trial was executed to compare the efficacy and safety of the supra-annular, self-expanding Evolut valve (SEV) with the intra-annular, balloon-expandable SAPIEN valve (BEV) in patients with severe symptomatic aortic stenosis and a small aortic valve annulus. It was a prospective, randomized controlled, all-comer, post-market trial in which 716 patients with all surgical risk categories including bicuspid patients were randomized to SEV or BEV.

The co-primary endpoints at 1 year were the composite of mortality, disabling stroke, or heart failure rehospitalization through 12 months, and bioprosthetic valve dysfunction through 12 months.

Main results

• The supra-annular SEV was non-inferior with regard to clinical outcomes at 1 year compared with BEV.
• Event rates of bioprosthetic valve dysfunction at 12 months was 9.4% in the SEV group and 41.6% in the BEV group, which showed superiority for SEV (difference -32.2%, 95%CI: -38.7% to -25.6%, P<0.001 for superiority).
• Other secondary endpoints showed superior valve performance at 1 year with SEV compared with BEV: 32.2% lower incidence of BVD, 8 mmHg lower mean gradient, 0.5 cm² greater effective orifice area, 0.19 larger Doppler velocity index, 6.8% lower incidence of sever PPM.
• The SEV group showed less total AR and better QoL per the KCCQ ordinal outcome compared with the BEV group.

Conclusion

In the SMART trial, the TAVR device SEV was noninferior to the BEV with regard to clinical outcomes. Moreover, bioprosthetic valve dysfunction at 12 months was lower in the SEV group than in the BEV group, with superior hemodynamic valve performance with SEV.

Prof. Herrmann stated that the Evolut platform is an ideal choice for patients with a small aortic annulus undergoing TAVR, most of whom are women. Furthermore, he noted that all patients with be followed through 5 years to demonstrate long-term efficacy and safety.

- Our reporting is based on the information provided at the ACC.24 Scientific Session -

The findings of this study were simultaneously published in N Engl J Med