Mechanical and morphometric study of mitral valve chordae tendineae and related papillary muscle

Chen, S., Ratna Sari, C., Gao, H. , Lei, Y., Segers, P. and De Beule, M. (2020) Mechanical and morphometric study of mitral valve chordae tendineae and related papillary muscle. Journal of the Mechanical Behavior of Biomedical Materials, 111, 104011. (doi: 10.1016/j.jmbbm.2020.104011)

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Abstract

The mitral valve (MV) apparatus is a complex mechanical structure including annulus, valve leaflets, papillary muscles (PMs) and connected chordae tendineae. Chordae anchor to the papillary muscles to help the valve open and close properly during one cardiac cycle. It is of paramount importance to understand the functional, mechanical, and microstructural properties of mitral valve chordae and connecting PMs. In particular, little is known about the biomechanical properties of the anterior and posterior papillary muscle and corresponding chords. In this work, we performed uniaxial and biaxial tensile tests on the anterolateral (APM) and posteromedial papillary muscle (PPM), and their respective corresponding chordae tendineae, chordaeAPM and chordaePPM, in porcine hearts. Histology was carried out to link the microstructure and macro-mechanical behavior of the chordae and PMs. Our results demonstrate that chordaePPM are less in number, but significantly longer and stiffer than chordaeAPM. These different biomechanical properties may be partially explained by the higher collagen core ratio and larger collagen fibril density of chordaePPM. No significant mechanical or microstructural differences were observed along the circumferential and longitudinal directions of APM and PPM samples. Data measured on chordae and PMs were further fitted with the Ogden and reduced Holzapfel - Ogden strain energy functions, respectively. This study presents the first comparative anatomical, mechanical, and structural dataset of porcine mitral valve chordae and related PMs. Results indicate that a PM based classification of chordae will need to be considered in the analysis of the MV function or planning a surgical treatment, which will also help developing more precise computational models of MV.

Item Type:Articles
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Gao, Dr Hao
Authors: Chen, S., Ratna Sari, C., Gao, H., Lei, Y., Segers, P., and De Beule, M.
College/School:College of Science and Engineering > School of Mathematics and Statistics > Mathematics
Journal Name:Journal of the Mechanical Behavior of Biomedical Materials
Publisher:Elsevier
ISSN:1751-6161
ISSN (Online):1878-0180
Published Online:30 July 2020
Copyright Holders:Copyright © 2020 The Authors
First Published:First published in Journal of the Mechanical Behavior of Biomedical Materials 111: 104011
Publisher Policy:Reproduced under a Creative Commons License

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Project CodeAward NoProject NamePrincipal InvestigatorFunder's NameFunder RefLead Dept
172141EPSRC Centre for Multiscale soft tissue mechanics with application to heart & cancerRaymond OgdenEngineering and Physical Sciences Research Council (EPSRC)EP/N014642/1M&S - Mathematics