Optimal elastomeric scaffold leaflet shape for pulmonary heart valve leaflet replacement

Abstract

Surgical replacement of the pulmonary valve (PV) is a common treatment option for congenital pulmonary valve defects. Engineered tissue approaches to develop novel PV replacements are intrinsically complex, and will require methodical approaches for their development. Single leaflet replacement utilizing an ovine model is an attractive approach in that candidate materials can be evaluated under valve level stresses in blood contact without the confounding effects of a particular valve design. In the present study an approach for optimal leaflet shape design based on finite element (FE) simulation of a mechanically anisotropic, elastomeric scaffold for PV replacement is presented. The scaffold was modeled as an orthotropic hyperelastic material using a generalized Fung-type constitutive model. The optimal shape of the fully loaded PV replacement leaflet was systematically determined by minimizing the difference between the deformed shape obtained from FE simulation and an ex-vivo microCT scan of a native ovine PV leaflet. Effects of material anisotropy, dimensional changes of PV root, and fiber orientation on the resulting leaflet deformation were investigated. In-situ validation demonstrated that the approach could guide the design of the leaflet shape for PV replacement surgery.

Fresh Pericardial Valved Conduit for Reconstruction of Right Ventricular Outflow Tract in Tetralogy of Fallot with Pulmonary Stenosis or Pulmonary Atresia—Early Results

“…1) They made bicuspid conduits whereas ours is tricuspid, 2) They used a trapezoid shaped strip to create valvular cusp, we use rectangular strip, 3) They didn't take the upper parabolic curvature into consideration as we did. We adopted our design from the cusp design described by Fan R. et al [4], Billar et al [5] and sinus drawings by Schäfers Hans-Joachim et al [15]. Schlichter The short period of competence of the APVC valve is a relative disadvantage.…”

“…After the wide experience with the use of unpreserved pericardium in the reconstruction of the right ventricular outflow tract in ToF, Schlichter Andrés J. et al produced excellent results [1]. We created and modified later a tricuspid valved conduit instead of Schlichter's bicuspid conduit by studying the normal pulmonary and aortic valve cusp diameters and cusp shapes [4] [5] [6].…”

Efficient computational simulation of actin stress fiber remodeling

“…For example, in heart valves, circumferentially aligned collagen fibers have been observed (Billiar & Sacks 2000a;Martin & Sun 2012) that transfer the pressure applied on the closed heart valve to the aortic wall (Peskin & McQueen 1994). Furthermore, they reinforce the circumferential direction enabling the stretch in the radial direction for a proper closure of the heart valve (Billiar & Sacks 2000a, 2000bSacks et al 2009;Martin & Sun 2012;Fan et al 2013;Loerakker et al 2013). Next to external loads (Ruberti & Hallab 2005;Bhole et al 2009;Wyatt et al 2009;De Jonge et al 2013), the collagen network is remodeled by contractile forces exerted by the cells along their principal direction, which is determined by the organization of actin stress fibers (Wang et al 2003;Ghibaudo et al 2008;Faust et al 2011).…”

Stability and Conservation Properties of Collocated Constraints in Immersogeometric Fluid-Thin Structure Interaction Analysis

“…Attempts to design more durable prostheses would benefit from understanding the stresses that drive this degradation process. Computational methods of structural analysis have yielded some insights into the mechanics of prosthetic valves and the organs they are modeled after [31][32][33][34][35][36][37][38][39][40][41][42][43][44][45][46][47], but such approaches typically approximate the effect of the fluid crudely, as a uniform pressure applied to each of the valve leaflets. The goal of studies on computational heart valve FSI, such as those cited earlier, is to account for the effect of the fluid more accurately.…”