TY - JOUR
T1 - Insights into the passive mechanical behavior of left ventricular myocardium using a robust constitutive model based on full 3D kinematics
AU - Li, David S.
AU - Avazmohammadi, Reza
AU - Merchant, Samer S.
AU - Kawamura, Tomonori
AU - Hsu, Edward W.
AU - Gorman, Joseph H.
AU - Gorman, Robert C.
AU - Sacks, Michael S.
N1 - Funding Information:
This work was supported by the National Institutes of Health (T32 EB007507 and F31 HL139113) to D.S.L. the National Institutes of Health and American Heart Association awards (K99 HL138288 and 18CDA34110383, respectively) to R.A. the National Institutes of Health (R01 HL63954) to R.C.G. and the W.A. Moncrief, Jr. SBES endowment to M.S.S. All specimen imaging was performed at the Preclinical Imaging Core Facility at the University of Utah.
Funding Information:
This work was supported by the National Institutes of Health ( T32 EB007507 and F31 HL139113 ) to D.S.L., the National Institutes of Health and American Heart Association awards ( K99 HL138288 and 18CDA34110383 , respectively) to R.A., the National Institutes of Health (R01 HL63954) to R.C.G., and the W.A. Moncrief, Jr. SBES endowment to M.S.S. All specimen imaging was performed at the Preclinical Imaging Core Facility at the University of Utah.
Publisher Copyright:
© 2019 Elsevier Ltd
PY - 2020/3
Y1 - 2020/3
N2 - Myocardium possesses a hierarchical structure that results in complex three-dimensional (3D) mechanical behavior, forming a critical component of ventricular function in health and disease. A wide range of constitutive model forms have been proposed for myocardium since the first planar biaxial studies were performed by Demer and Yin (J. Physiol. 339 (1), 1983). While there have been extensive studies since, none have been based on full 3D kinematic data, nor have they utilized optimal experimental design to estimate constitutive parameters, which may limit their predictive capability. Herein we have applied our novel 3D numerical-experimental methodology (Avazmohammadi et al., Biomechanics Model. Mechanobiol. 2018) to explore the applicability of an orthotropic constitutive model for passive ventricular myocardium (Holzapfel and Ogden, Philos. Trans. R. Soc. Lond.: Math. Phys. Eng. Sci. 367, 2009) by integrating 3D optimal loading paths, spatially varying material structure, and inverse modeling techniques. Our findings indicated that the initial model form was not successful in reproducing all optimal loading paths, due to previously unreported coupling behaviors via shearing of myofibers and extracellular collagen fibers in the myocardium. This observation necessitated extension of the constitutive model by adding two additional terms based on the I8(C) pseudo-invariant in the fiber-normal and sheet-normal directions. The modified model accurately reproduced all optimal loading paths and exhibited improved predictive capabilities. These unique results suggest that more complete constitutive models are required to fully capture the full 3D biomechanical response of left ventricular myocardium. The present approach is thus crucial for improved understanding and performance in cardiac modeling in healthy, diseased, and treatment scenarios.
AB - Myocardium possesses a hierarchical structure that results in complex three-dimensional (3D) mechanical behavior, forming a critical component of ventricular function in health and disease. A wide range of constitutive model forms have been proposed for myocardium since the first planar biaxial studies were performed by Demer and Yin (J. Physiol. 339 (1), 1983). While there have been extensive studies since, none have been based on full 3D kinematic data, nor have they utilized optimal experimental design to estimate constitutive parameters, which may limit their predictive capability. Herein we have applied our novel 3D numerical-experimental methodology (Avazmohammadi et al., Biomechanics Model. Mechanobiol. 2018) to explore the applicability of an orthotropic constitutive model for passive ventricular myocardium (Holzapfel and Ogden, Philos. Trans. R. Soc. Lond.: Math. Phys. Eng. Sci. 367, 2009) by integrating 3D optimal loading paths, spatially varying material structure, and inverse modeling techniques. Our findings indicated that the initial model form was not successful in reproducing all optimal loading paths, due to previously unreported coupling behaviors via shearing of myofibers and extracellular collagen fibers in the myocardium. This observation necessitated extension of the constitutive model by adding two additional terms based on the I8(C) pseudo-invariant in the fiber-normal and sheet-normal directions. The modified model accurately reproduced all optimal loading paths and exhibited improved predictive capabilities. These unique results suggest that more complete constitutive models are required to fully capture the full 3D biomechanical response of left ventricular myocardium. The present approach is thus crucial for improved understanding and performance in cardiac modeling in healthy, diseased, and treatment scenarios.
KW - Constitutive modeling
KW - Inverse modeling
KW - Optimal experimental design
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U2 - 10.1016/j.jmbbm.2019.103508
DO - 10.1016/j.jmbbm.2019.103508
M3 - Article
C2 - 32090941
AN - SCOPUS:85075888158
VL - 103
JO - Journal of the Mechanical Behavior of Biomedical Materials
JF - Journal of the Mechanical Behavior of Biomedical Materials
SN - 1751-6161
M1 - 103508
ER -