title: Characterizing the collagen fiber orientation in pericardial leaflets under mechanical loading conditions.
abstract: When implanted inside the body, bioprosthetic heart valve leaflets experience a variety of cyclic mechanical stresses such as shear stress due to blood flow when the valve is open, flexural stress due to cyclic opening and closure of the valve, and tensile stress when the valve is closed. These types of stress lead to a variety of failure modes. In either a natural valve leaflet or a processed pericardial tissue leaflet, collagen fibers reinforce the tissue and provide structural integrity such that the very thin leaflet can stand enormous loads related to cyclic pressure changes. The mechanical response of the leaflet tissue greatly depends on collagen fiber concentration, characteristics, and orientation. Thus, understating the microstructure of pericardial tissue and its response to dynamic loading is crucial for the development of more durable heart valve, and computational models to predict heart valves' behavior. In this work, we have characterized the 3D collagen fiber arrangement of bovine pericardial tissue leaflets in response to a variety of different loading conditions under Second-Harmonic Generation Microscopy. This real-time visualization method assists in better understanding of the effect of cyclic load on collagen fiber orientation in time and space.
authors.affiliation: The Edwards Lifesciences Center for Advanced Cardiovascular Technology, Department of Biomedical Engineering, University of California, Irvine, Irvine, CA 92697, USA.
authors.forename: S Hamed
authors.initials: SH
authors.lastname: Alavi
authors.forename: Victor
authors.initials: V
authors.lastname: Ruiz
authors.forename: Tatiana
authors.initials: T
authors.lastname: Krasieva
authors.forename: Elliot L
authors.initials: EL
authors.lastname: Botvinick
authors.forename: Arash
authors.initials: A
authors.lastname: Kheradvar
mesh_terms: D000818:Animals; D001696:Biomechanical Phenomena; D001698:Biomedical Engineering / Q000295:instrumentation; D001705:Bioprosthesis; D002417:Cattle; D003094:Collagen / Q000737:chemistry* / Q000502:physiology*; D019544:Equipment Failure Analysis / Q000295:instrumentation; D006350:Heart Valve Prosthesis; D006801:Humans; D008955:Models, Cardiovascular; D010496:Pericardium / Q000737:chemistry* / Q000502:physiology*; D013314:Stress, Mechanical
chemical_list: D003094:Collagen