Rationale and design of the SMall Annuli Randomized To Evolut or SAPIEN Trial (SMART Trial)

Background: The SMall Annuli Randomized To Evolut or SAPIEN (SMART) Trial was designed to compare the performance of the two most widely available commercial transcatheter aortic valve replacement (TAVR) devices in patients with symptomatic severe native aortic stenosis with a small aortic valve annulus undergoing transfemoral TAVR. Patients with small aortic valve annuli are typically female and are often underrepresented in clinical trials.

Methods: The SMART Trial is an international, prospective, multi-center, randomized controlled, post-market trial. The trial will be conducted in approximately 700 subjects at approximately 90 sites globally. Inclusion criteria include severe aortic stenosis, aortic valve annulus area of ≤430 mm² based on multi-detector computed tomography, and appropriate anatomy for both the Medtronic Evolut PRO/PRO+ self-expanding and Edwards SAPIEN 3/3 Ultra balloon-expandable devices. The primary clinical outcome composite endpoint is defined as mortality, disabling stroke or heart failure rehospitalization at 12 months. The co-primary valve function composite endpoint is defined as bioprosthetic valve dysfunction at 12 months which includes hemodynamic structural valve dysfunction, defined as a mean gradient ≥20 mmHg, non-structural valve dysfunction, defined as severe prothesis-patient mismatch or ≥moderate aortic regurgitation, thrombosis, endocarditis, and aortic valve re-intervention. Powered secondary endpoints will be assessed hierarchically.

Conclusions: The SMART trial will be the largest head-to-head comparative trial of transfemoral TAVR using the two most widely available contemporary TAVR devices in the setting of small aortic annuli and the largest trial to enroll primarily women.

Clinical trial registration: URL: www.clinicaltrials.gov, Unique identifier: NCT04722250.