Towards 3D analysis of aortic heart valve

Towards 3D analysis of aortic heart valve

Javani Joni, H., Oomens, C. W. J., & Baaijens, F. P. T. (2011). Towards 3D analysis of aortic heart valve. Poster session presented at Mate Poster Award 2011 : 16th Annual Poster Contest.

Document status and date: Published: 01/01/2011 Document Version:

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Soft Tissue Biomechanics & Engineering

Towards 3D analysis of Aortic

Heart Valve

H. R. Javani, C. W. J. Oomens and F. P. T. Baaijens

/department of biomedical engineering

Introduction

A diseased heart valve must be replaced by a prosthetic device in order to continue the function performed by the natural valve -see Figure 1. These prosthetic devices can not perform the function of heart valve with the same efficiency and durability. Therefore, numerical and experimental studies are widely per-formed to improve the function and avoid their failure.

Fig. 1Two-dimensional representation of the aortic valve [1].

Objective

On one hand developing a fully three dimensional numerical tools for the interaction between heart valve and blood (fluid-structure interaction) and on the other hand studying the be-havior of the heart valve prosthetic device under such a bound-ary conditions.

Method and results

There is a delicate and complex interaction between the heart valve and the surrounding blood. This interaction (fluid-solid) has to be considered for an accurate mechanical and hemody-namical aspects of the valve behavior.

Fig. 2Background FEM Ω1

f, fat boundary layer Ω2f and solid Ωs[2].

Here we take the 2D algorithm developed by Bogaerds et al. [2] as the starting point and using Finite Element (instead of spec-tral element in [2]) the coupling scheme is being transferred to real three dimensional applications. A so called fat bound-ary layer is connected to the solid and the fluid variables in the interface between the two fluids (boundary layer and back-ground) are connected -see Figure 2.

In the presented approach, the proper coupling of the two fluid domains is the challenging part since the fluid and solid are connected using conforming meshes. The governing equations for the two fluid domains are Navier-Stokes equations:

∂ρv

ρt + ∇ · ρvv = ∇ · σf σf = 2ηD − pfI

∇ · v _{= 0 (1)}

and the coupling conditions for their interface:

v

1 = v2

(σ1

f− σ2f) · nf si = 0 (2)

The Baumann and Oden stabilized technique is used for cou-pling on fluid-fluid interface. Figure 3 shows how this technique is used to couple two partially overlapping finite element layer.

-0.1666 -0.1 0 0.1 0.2 Pressure

Fig. 3Coupling the background and foreground finite element mesh.

Conclusion & Further extension

The 2D approach will be extended to three dimensional prob-lems for studying the behavior and loading conditions of the heart valve.

References:

[1] J. de Hart. Fluid-Structure Interaction in the Aortic Heart Valve a three-dimensional computational analysis. PhD thesis, Eind-hoven University of Technology, 2002.