title: Effects of valve geometry and tissue anisotropy on the radial stretch and coaptation area of tissue-engineered heart valves.
abstract: Tissue engineering represents a promising technique to overcome the limitations of the current valve replacements, since it allows for creating living autologous heart valves that have the potential to grow and remodel. However, also this approach still faces a number of challenges. One particular problem is regurgitation, caused by cell-mediated tissue retraction or the mismatch in geometrical and material properties between tissue-engineered heart valves (TEHVs) and their native counterparts. The goal of the present study was to assess the influence of valve geometry and tissue anisotropy on the deformation profile and closed configuration of TEHVs. To achieve this aim, a range of finite element models incorporating different valve shapes was developed, and the constitutive behavior of the tissue was modeled using an established computational framework, where the degree of anisotropy was varied between values representative of TEHVs and native valves. The results of this study suggest that valve geometry and tissue anisotropy are both important to maximize the radial strains and thereby the coaptation area. Additionally, the minimum degree of anisotropy that is required to obtain positive radial strains was shown to depend on the valve shape and the pressure to which the valves are exposed. Exposure to pulmonary diastolic pressure only yielded positive radial strains if the anisotropy was comparable to the native situation, whereas considerably less anisotropy was required if the valves were exposed to aortic diastolic pressure.
authors.affiliation: Department of Biomedical Engineering, Eindhoven University of Technology, PO Box 513, 5600 MB Eindhoven, The Netherlands. s.loerakker@tue.nl
authors.forename: S
authors.initials: S
authors.lastname: Loerakker
authors.forename: G
authors.initials: G
authors.lastname: Argento
authors.forename: C W J
authors.initials: CW
authors.lastname: Oomens
authors.forename: F P T
authors.initials: FP
authors.lastname: Baaijens
mesh_terms: D016880:Anisotropy; D001696:Biomechanical Phenomena; D001705:Bioprosthesis; D020342:Finite Element Analysis; D006350:Heart Valve Prosthesis; D006351:Heart Valves / Q000033:anatomy & histology* / Q000502:physiology*; D006801:Humans; D008955:Models, Cardiovascular; D023822:Tissue Engineering; D054457:Tissue Scaffolds
keywords: Collagen; Constitutive modeling; Finite element modeling; Leaflet retraction; Tissue engineering