Key result
A finite element model demonstrated that the saddle shape and contraction of the annulus benefit valve coaptation and decrease leaflet loads, while chordae tendineae prevent leaflet turnover.
Effect estimate: r = 0.965
Computational modeling demonstrates that the saddle shape and contraction of the mitral annulus, along with intact chordae tendineae, are essential for proper valve coaptation and stress distribution.
Supports chordae preservation for leaflet stability; hypothesis-generating from animal models, requiring human validation.
Objectives: To investigate the influences caused by special morphologies and dynamics of the substructures of mitral valve by the explicit finite element program LS-DYNA. Methods: A new finite element model for the mitral apparatus characterized by layered structure of leaflets tissue, saddle shape and contraction of annulus, an approximately accurate morphology of chordae tendineae was developed. The coaptation length, leaflets stress and strain of the present model were compared with those of two auxiliary models, one with planar annulus and the other with fixed annulus. The tensile function and force distribution of chordae tendineae were analyzed in the models with and without chordae tendineae. Results: The stretch ratios computed by the present model were most closely to the experimental data. The leaflets instantly turned over to the atrial side and larger load was observed in the model without chordae tendineae. Besides, tensile force was highly correlated with average diameter of chordae tendineae (r = 0.965). Conclusion: The saddle shape of annulus benefits valve coaptation and the contraction of annulus could help decrease loads on leaflets and prevent stress concentrating excessively. Chordae tendineae could bear partial loads on the leaflets, and prevent the leaflets to turn over to the side of the atrium and help the valve close successfully.
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Zhong et al. (2014) studied Mitral valve mechanics. Finite element model with saddle shape and contraction of annulus and chordae tendineae vs. Models with planar annulus, fixed annulus, or without chordae tendineae was evaluated on Coaptation length, leaflets stress and strain, tensile function and force distribution (r = 0.965). A finite element model demonstrated that the saddle shape and contraction of the annulus benefit valve coaptation and decrease leaflet loads, while chordae tendineae prevent leaflet turnover.
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