Introduction: The Challenge of the Small Surgical Valve
As the prevalence of bioprosthetic aortic valve replacement has increased, the medical community is facing a growing cohort of patients presenting with bioprosthetic valve dysfunction (BVD). Valve-in-valve (ViV) transcatheter aortic valve replacement (TAVR) has emerged as a less invasive alternative to redo surgical aortic valve replacement. However, patients with small surgical bioprostheses—typically defined as a labeled size of ≤23 mm—present a unique clinical challenge. The internal diameter of these valves is inherently restricted, which increases the risk of high post-procedural gradients and prosthesis-patient mismatch (PPM) after a ViV procedure.
While retrospective registries have suggested differences in performance between various transcatheter heart valve (THV) designs, prospective randomized data have been sparse. The LYTEN trial (Comparison of the Balloon-Expandable Edwards Valve and Self-Expanding CoreValve Evolut R or Evolut PRO System for the Treatment of Small, Severely Dysfunctional Surgical Aortic Bioprostheses) was designed to address this gap, providing much-needed evidence to guide device selection in this high-risk population.
