Benchtop characterization of the tricuspid valve leaflet pre-strains
Date
2022-10-15
Authors
Laurence, Devin W.
Ross, Colton J.
Mir, Arshid
Burkhart, Harold M.
Holzapfel, Gerhard A.
Lee, Chung-Hao
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Elsevier Ltd.
Abstract
The pre-strains of biological soft tissues are important when relating their in vitro and in vivo mechanical behaviors. In this study, we present the first-of-its-kind experimental characterization of the tricuspid valve leaflet pre-strains. We use 3D photogrammetry and the reproducing kernel method to calculate the pre-strains within the central 10 x 10 mm region of the tricuspid valve leaflets from n = 8 porcine hearts. In agreement with previous pre-strain studies for heart valve leaflets, our results show that all the three tricuspid valve leaflets shrink after being explanted from the ex vivo heart. These calculated strains are leaflet-specific and the septal leaflet experiences the most compressive changes. Furthermore, the strains observed after dissection of the central 10 x 10 mm region of the leaflet are smaller than when the valve is explanted, suggesting that our computed pre-strains are mainly due to the release of in situ annulus and chordae connections. The leaflets are then mounted on a biaxial testing device and preconditioned using force-controlled equibiaxial loading. We show that the employed preconditioning protocol does not 100% restore the leaflet pre-strains as removed during tissue dissection, and future studies are warranted to explore alternative preconditioning methods. Finally, we compare the calculated biomechanically oriented metrics considering five stress-free reference configurations. Interestingly, the radial tissue stretches and material anisotropies are significantly smaller compared to the post-preconditioning configuration. Extensions of this work can further explore the role of this unique leaflet-specific leaflet pre-strains on in vivo valve behavior via high-fidelity in-silico models.
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Comments
This is a manuscript of an article published as Laurence, Devin W., Colton J. Ross, Ming-Chen Hsu, Arshid Mir, Harold M. Burkhart, Gerhard A. Holzapfel, and Chung-Hao Lee. "Benchtop characterization of the tricuspid valve leaflet pre-strains." Acta Biomaterialia 152 (2022): 321-334.
DOI: 10.1016/j.actbio.2022.08.046.
Copyright 2022 Acta Materialia Inc.
Posted with permission.