Comparative mechanical, morphological, and microstructural characterization of porcine mitral and tricuspid leaflets and chordae tendineae

• Type of Material: Article
• Authors: Anastassia Pokutta-Paskaleva, Georgia Institute of Technology; Fatiesa Sulejmani, Georgia Institute of Technology; Marissa DelRocini, Rutgers University; Wei Sun, Emory University
• Language: English
• Date: 2019-02-01
• Publisher: Elsevier
• Publication Version: Author Accepted Manuscript (After Peer Review)
• Copyright Statement: © 2018 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.
• License: Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International
• Final Published Version (URL): http://dx.doi.org/10.1016/j.actbio.2018.12.029
• Title of Journal or Parent Work: Acta Biomaterialia
• Volume: 85
• Start Page: 241
• End Page: 252
• Grant/Funding Information: Additionally, Fatiesa Sulejmani is supported by the Georgia Institute of Technology-Emory University-Peking University Global Biomedical Engineering Research and Education Fellowship.; This research is funded in part by NIH HL127570 and NIH HL104080 grants.
• Keywords: Comparative characterization; uniaxial testing; tricuspid valve mechanics; tricuspid regurgitation; biaxial testing; Health function; chordae tendineae
• Research Categories: Engineering, Biomedical; Biology, Physiology; Biology, Biostatistics; Health Sciences, Immunology

Abstract

Background: Healthy function of tricuspid valve (TV) structures is essential to avoid tricuspid regurgitation (TR) and may significantly improve disease prognosis. Mitral valve (MV) structures have been extensively studied, but little is known about the TV and right-sided heart diseases. Therefore, clinical decisions and finite element (FE) simulations often rely heavily on MV data for TV applications, despite fundamentally different mechanical and physiological environments. Method/Results: To bridge this gap, we performed a rigorous mechanical, morphological, and microstructural characterization of the MV and TV leaflets and chordae in a porcine model. Planar biaxial testing, uniaxial testing, second harmonic generation imaging and Verhoeff Van Gieson staining were performed. Morphological parameters, tissue moduli, extensibility, and anisotropy were quantified and compared. No major differences in leaflet mechanics or structure were found between TV and MV; chordal mechanics, morphology, and structure were found to compensate for anatomical and physiological loading differences between the valves. No differences in chordal mechanics were observed by insertion point within a leaflet; the septal tricuspid leaflet (STL) and posterior mitral leaflet (PML) did not have distinguishable strut chords, and the STL had the shortest chords. Within a valve, chords from septally-located leaflets were more extensible. MV chords were stiffer. Conclusions: This study presents the first rigorous comparative mechanical and structural dataset of MV and TV structures. Valve type and anatomical location may be stronger predictors of chordal mechanics. Chords from septally-located leaflets differ from each other and from their intravalvular counterparts; they merit special consideration in surgical and computational applications.