Simulated transcatheter aortic valve deformation: A parametric study on the impact of leaflet geometry on valve peak stress

Abstract

In this study, we developed a computational framework to investigate the impact of leaflet geometry of a transcatheter aortic valve (TAV) on the leaflet stress distribution, aiming at optimizing TAV leaflet design to reduce its peak stress. Utilizing a generic TAV model developed previously [Li and Sun, Annals of Biomedical Engineering, 2010. 38(8): 2690-2701], we first parametrized the 2D leaflet geometry by mathematical equations, then by perturbing the parameters of the equations, we could automatically generate a new leaflet design, remesh the 2D leaflet model and generate a 3D leaflet model from the 2D design via a Python script. Approximately 500 different leaflet designs were investigated by simulating TAV closure under the nominal circular deployment and physiological loading conditions. From the simulation results, we identified a new leaflet design that could reduce the previously reported valve peak stress by about 5%. The parametric analysis also revealed that increasing the free edge width had the highest overall impact on decreasing the peak stress. A similar computational analysis was further performed for a TAV deployed in an abnormal, asymmetric elliptical configuration. We found that a minimal free edge height of 0.46 mm should be adopted to prevent central backflow leakage. This increase of the free edge height resulted in an increase of the leaflet peak stress. Furthermore, the parametric study revealed a complex response surface for the impact of the leaflet geometric parameters on the peak stress, underscoring the importance of performing a numerical optimization to obtain the optimal TAV leaflet design.

Assessment of heart valve performance by finite-element design studies of polymeric leaflet-structures

“…The influence of various design parameters on the leaflet performance has been investigated in structural mechanical FEA, previously [3][4][5]. Within the current work, we used FEA parametric studies for the design of a novel polymeric leaflet-structure for transcatheter heart valves.…”

Combining statistical shape modeling, CFD, and meta‐modeling to approximate the patient‐specific pressure‐drop across the aortic valve in real‐time

“…Although the aortic valve has a complex shape and function, various authors proposed simplified parametric models. 2,[53][54][55] These parametric models facilitate parametric numerical simulations. For example, to study: collagen remodeling 54 ; the effect of aortic valve geometry on peak-stress, 2 or bi-cuspid geometry on ascending aorta hemodynamics.…”

“…2,[53][54][55] These parametric models facilitate parametric numerical simulations. For example, to study: collagen remodeling 54 ; the effect of aortic valve geometry on peak-stress, 2 or bi-cuspid geometry on ascending aorta hemodynamics. 56 Such parametric models are particularly powerful for obtaining fundamental understanding of the involved physics, and for determining the most relevant physical parameters.…”

Simulated Transcatheter Aortic Valve Flow: Implications of Elliptical Deployment and Under‐Expansion at the Aortic Annulus

“…Only one initial leaflet geometry was used to create the abnormal TAV models. Alternative initial leaflet geometries may generate different results . However, it is expected that the overall trends in pressure gradient and flow patterns will hold for different TAV designs.…”