Supra-annular sizing method at neo hinge plane in type 0 bicuspid aortic valve

Bicuspid aortic valve (BAV) disease is characterized by remarkable anatomic heterogeneity that significantly affects transcatheter aortic valve replacement (TAVR) outcomes. As TAVR expands toward younger and lower-risk populations, the prevalence of bicuspid anatomy—particularly Sievers type 0—will inevitably increase, creating a new clinical need for dedicated sizing strategies. Type 0 BAV, defined by two symmetric cusps and absence of a raphe, presents unique challenges due to its elliptic annulus, "fish-mouth" orifice, and asymmetric calcification, which often hinder uniform prosthesis expansion and sealing, leading to paravalvular leak (PVL). Despite technological advances, PVL remains more frequent in type 0 BAV than in tricuspid aortic valve stenosis. Conventional annular-based sizing may cause over- or undersizing, increasing the risk of annular injury or residual regurgitation. A refined, anatomy-driven sizing approach is therefore crucial to optimize valve–root interaction and procedural safety.

This study introduces a novel supra-annular sizing concept for type 0 BAV, based on the identification of the "neo-hinge plane," connecting the two points where the cusps begin to yield and open during systole. This dynamic plane represents the physiologic transition between the fixed and mobile leaflet portions and the true level of prosthesis–leaflet interaction. The objective of this work was to evaluate the feasibility, safety, and early clinical performance of this neo-hinge plane–based sizing method in patients with type 0 BAV undergoing TAVR with self-expanding valves.

Between 2019 and 2025, seven consecutive patients with type 0 BAV underwent TAVR at IRCCS San Raffaele Hospital using the neo-hinge perimeter for valve sizing. Unlike conventional annular sizing, this method measures the perimeter at the neo-hinge plane, the supra-annular level of maximal symmetric constraint. Given that BAV is a marker of aortopathy, balloon-expandable valves were avoided to reduce rupture risk; the method was designed for self-expanding prostheses. Outcomes were defined according to VARC-3 criteria.

All procedures were completed successfully, 86% transfemoral and 14% transaxillary. The neo-hinge perimeter was smaller than the annular perimeter, confirming a distinct supra-annular constraint. Device success was achieved in 6/7 patients (86%), with one moderate PVL. There were no deaths, annular ruptures, or major complications. Post-dilatation was performed in 43%, and mean implantation depth was 4.3 ± 1.2 mm above the VBR. The mean gradient was 8 ± 4 mmHg, with no severe PVL. One permanent pacemaker was implanted (14%).

The neo-hinge plane–based supra-annular sizing method is feasible, safe, and anatomically consistent for self-expanding TAVR in type 0 BAV. Sizing at the functional supra-annular level allows more accurate prosthesis selection and improved sealing while minimizing PVL and annular stress.