Additional analysis from the SMART trial has demonstrated clinical non-inferiority of self-expanding valves versus balloon-expandable valves in aortic stenosis patients undergoing transcatheter aortic valve implantation (TAVI) and confirmed valve performance superiority over time based on haemodynamics.
Data also showed similar positive results in two age groups (< or ≥80 years old). The late-breaking results were presented at the Society for Cardiovascular Angiography & Interventions (SCAI) 2024 scientific sessions (2–4 May, Long Beach, USA).
The SMART randomised trial compared the supra-annular self-expanding Evolut (Medtronic) family of TAVI valves, which includes the Evolut PRO, PRO+ and FX iterations of the system, and the balloon-expandable Sapien 3 and Sapien 3 Ultra (Edwards Lifesciences).
The trial is the first 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 TAVI.
Patients with aortic stenosis and small aortic annuli, typically female and underrepresented in clinical trials, are at risk for impaired valvular haemodynamics, or blood flow and associated adverse cardiovascular outcomes following TAVI. The underrepresentation of women in research and the severity of the condition creates a call for more clinical data.
The SMART trial is an international, prospective, multicentre, randomised (1:1) post-market trial comparing the safety and performance of self-expanding versus balloon-expandable valves in TAVI patients with symptomatic severe aortic stenosis and small aortic annulus.
Eligible patients had an aortic valve annulus area of less than or equal to 430mm2 by CT and suitable anatomy for transfemoral TAVI with an Evolut or a Sapien 3 valve. The co-primary endpoints were: a clinical outcome composite of mortality, disabling stroke, or heart failure rehospitalisation; and a valve function composite of bioprosthetic valve dysfunction (BVD) through 12 months.
A total of 716 patients (87% women, mean age 80 years) were treated at 83 sites. The SMART trial met both primary endpoints. Compared with balloon-expandable valve, the self-expanding valve demonstrated non-inferior clinical outcomes and superior valve performance as measured by multiple definitions of BVD as well as by standard haemodynamics (doppler velocity index [DVI], effective orifice area [EOA], severe prosthesis‐patient mismatch [PPM], mean gradient >20 mmHg) at one year.
As an additional analysis, the haemodynamics over time were evaluated and found to be similar between cohorts at baseline and favoured the self-expanding compared to balloon-expandable valve at all follow-up time points through 12 months (p<0.001). The results were also consistent in patients with age < or ≥80 years. Balloon-expandable valves had a BVD difference of 39.8% for patients <80 years old, and a BVD difference of 27.1% for patients ≥ 80 years old (both p<0.001).
“The SMART trial is the largest, most rigorous trial to date to randomise patients using the two most widely used TAVI devices, and the largest TAVI trial to enrol mostly women. We are excited to reiterate our previously presented findings in front of the interventional cardiologist community with our additional analysis,’’ said Howard Herrmann (Perelman School of Medicine at the University of Pennsylvania, Philadelphia, USA), the lead author of the study. “This confirms the haemodynamic 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.”
