Transcatheter Valve Underexpansion Limits Leaflet Durability: Implications for Valve-in-Valve Procedures

Abstract

Transcatheter aortic valve (TAV) implantation within a failed bioprosthetic valve is a growing trend for high-risk patients. The non-compliant stent of the previous prosthesis may prevent full expansion of the TAV, which has been shown to distort the leaflet configuration, and has been hypothesized to adversely affect durability. In this study, TAV leaflet fatigue damage under cyclic pressurization in the setting of stent underexpansion by 0 (fully expanded), 1, 2 and 3 mm was simulated using finite element analysis to test this hypothesis. In the 2 and 3 mm underexpanded devices, the TAV leaflets exhibited severe pin-wheeling during valve closure, which increased leaflet stresses dramatically, and resulted in accelerated fatigue damage of the leaflets. The leaflet fatigue damage in the 1 mm underexpanded case was similar to that in the fully expanded case. Clinically a range of 10% to 15% underexpansion is generally considered acceptable; however, it was observed in this study that ≥2 mm (≥9.1%) underexpansion, will significantly impact device durability. Further study is necessary to determine the impact of various deployment conditions, i.e. non-uniform and non-circular deployments and different implantation heights, on differing TAV devices, but it is clear that the normal TAV leaflet configuration must be preserved in order to preserve durability.

Novel Polymeric Valve for Transcatheter Aortic Valve Replacement Applications: In Vitro Hemodynamic Study

“…In comparison, When we tested the valves at full expansion (no oversizing), no pinwheeling was observed (see Online Appendix 3). Since the eventual intended use of the polymeric TAV is under oversizing of 5% and more, and since pinwheeling might have an effect on the valve durability, 21 we will likely make the free edges of the polymeric leaflet shorter in the next design iteration.…”

Characterization of mechanical properties of pericardium tissue using planar biaxial tension and flexural deformation

“…A previously described FE model of a generic, 23 mm transcatheter aortic valve ( TAV ) (34, 35) was used in this study. One TAV model was created for each tissue group: BPN, BPK, PPN and PPK.…”

Transcaval Valve-in-Valve-in-Valve Aortic Valve Replacement for Bioprosthetic Valve Degeneration

“…6 As younger and lower risk patients are treated with TAVR, limited durability of valvein-valve therapy may prove to be a disadvantage. There is evidence of worse valve-in-valve outcomes in patients with smaller surgical valves, 7 and valve underexpansion 8 is an important consideration for valve-in-valve-in-valve therapy. While a size 23 surgical valve can accommodate subsequent valve-in-valve treatment, a larger valve at the time of surgical aortic valve replacement may have afforded improved gradients with repeated interventions.…”