Finite element analysis of the mitral apparatus: annulus shape effect and chordal force distribution

Abstract

This study presents a three-dimensional finite element model of the mitral apparatus using a hyperelastic transversely isotropic material model for the leaflets. The objectives of this study are to illustrate the effects of the annulus shape on the chordal force distribution and on the mitral valve response during systole, to investigate the role of the anterior secondary (strut) chordae and to study the influence of thickness of the leaflets on the leaflets stresses. Hence, analyses are conducted with a moving and fixed saddle shaped annulus and with and without anterior secondary chordae. We found that the tension in the secondary chordae represents 31% of the load carried by the papillary muscles. When removing the anterior secondary chordae, the tension in the primary anterior chordae is almost doubled, the displacement of the anterior leaflet toward the left atrium is also increased. The moving annulus configuration with an increasing annulus saddle height does not give significant changes in the chordal force distribution and in the leaflet stress compared to the fixed annulus. The results also show that the maximum principle stresses in the anterior leaflet are carried by the collagen fibers. The stresses calculated in the leaflets are very sensitive to the thickness employed.

Towards Patient-Specific Finite-Element Simulation of MitralClip Procedure

“…4, right panel). Nonetheless, correct coaptation could be simulated by adjusting the rest length of selected chordae, which confirms their importance in MV function [9]. Simulation speed was ≈ 4 frames per second (f ps).…”

“…1), F c, . Pressures being not available, we apply a generic profile that increases from 0 mmHg to 120 mmHg [9]. The motion of the papillary heads, modeled as spatial points, and of the mitral annulus is prescribed from the automatic detection.…”

“…The motion of the papillary heads, modeled as spatial points, and of the mitral annulus is prescribed from the automatic detection. This contribution is of fundamental importance as valve closure highly depends on the papillary positions and the shape of the annulus during systole [9]. As mitral clip modifies the leaflets morphology only, it is reasonable to assume that the acute motion of the annulus and papillaries stays unchanged (it depends mostly on the ventricular mechanics).…”

“…Several constitutive laws have been proposed, from simple isotropic linear elasticity to more complex anisotropic non-linear hyper-elasticity [9,11,13]. Fluid-structure interaction models have also been investigated [2].…”

From real-time 3D echocardiography to mitral valve finite element analysis: A novel modeling approach

“…Indeed, FEMs have the potential to quantitatively analyze MV biomechanics, with great benefits as compared to traditional animal models: absence of ethical issues, local quantification of mechanical parameters, control on the multiple factors leading the behaviour of the simulated system and, thus, the capability to answer "what if" questions. Thanks to such potential, FEMs have been recently applied to study MV normal function [1][2][3], the biomechanics underlying MV diseases [1] and effects of surgical corrections [4][5][6][7]. However, none of the mentioned studies captures all of the four aspects that drive MV function: morphology, tissues mechanical response, dynamic boundary conditions and interaction between the MV and surrounding blood.…”