Selection of Transcatheter Heart vaLve With Intermediate Sizing in Patients With Severe Aortic Stenosis Treated With Transcatheter Aortic Valve Replacement

Transcatheter aortic valve implantation (TAVI) has evolved into a standard therapy for severe aortic stenosis across all surgical risk profiles, supported by pivotal trials in high- and low-risk populations. Two types of transcatheter heart valves, balloon-expandable and self-expanding, exhibit distinct hemodynamic and structural characteristics that influence procedural strategy and long-term durability. Accurate valve sizing is crucial for procedural success, as both undersizing and oversizing are associated with procedural complications, including aortic regurgitation, conduction disorders, valve embolization, annular rupture, and increased leaflet stress which may impair long-term durability. However, optimal annular sizing remains challenging due to the complex three-dimensional anatomy of the aortic annulus, which is oval, crown-shaped, dynamically deforming, and variably oriented. These anatomical features often lead to "grey zones" in clinical sizing charts, resulting in so-called borderline annuli in which the measured annular dimensions may indicate two suitable valve sizes. Borderline annuli are frequently encountered in patients undergoing TAVI with self-expanding valves (i.e., Evolut transcatheter heart valve series) due to a limited number of sizes (23, 26, 29 and 34 mm). Consequently, under- or oversizing of self-expanding valves is often required. However, sizing of transcatheter heart valves in borderline annuli is associated with a greater likelihood of procedural complications, higher rates of aortic regurgitation, and higher transvalvular gradients.9,11 New generation balloon-expandable valves (i.e., Myval transcatheter heart valve series) are introduced with intermediate (21.5, 24.5, 27.5 mm) and extra-large (30.5, 32 mm) valve sizes that are not available for the Evolut platform. These additional size ranges potentially offer more precise annular sizing, reducing the need for under- or oversizing and improving short- and long-term hemodynamic p