ARUP; ISBN: 978-0-9562121-5-3 - CMBBE 2012 - Cardiff University

Modeling of blood flow through a flexible aortic heart valve in different
heart rates
1 1 2 3
H.R.Ghasemi Bahraseman , K.Hassani , M.Navidbakhsh , N.Fatouraee ,
4 5
D.M.Espino , Z.Alizadeh.Sani
1. ABSTRACT
In this study, we have tried to model the blood flow across the aortic valve which the
valve acts completely flexible. The obtained data are very important for analysis of
flow rate variation in a 2D model. Using a commercially available software,COMSOL,
we have presented a model which enables us to calculate the cardiac output/stroke
volume with respect to variation of blood flow domain, geometry , changes in
boundary conditions for aortic valves (due to age , sex ,and diseases). Our results show
new methodology for investigation of the aortic heart valve operation that could be used
for design and manufacturing o f the artificial heart valves. The problem of the existing
models includes inability of modeling the contact phase in which the leaflets collide at
the end of systole. Therefore, we have used a gap in the model to avoid the contact of
the leaflets during closure phase to survive the fluid mesh. The presented model helps
the researchers to avoid expensive experimental methods. The modeling has been done
by finite element method as well as fluid-structure-interaction equations and ALE
(Arbitrary Lagrangian-Eulerian Formulation) method. Furthermore, we have done the
simulations both in rest and exercise conditions. The results, including the cardiac
output and stroke volume, have been extracted in accordance with the left ventricular
pressure, aortic pressure, and the heart rate. Furthermore, the model was compared to
the clinical data available in the literature.
2. INTRODUCTION
There are two main methods for numerical modeling of heart valves and analysis of
fluid field. In the first one, the displacement of the fluid boundary is defined and the
fluid field is solved using governing equations. The second method uses fluid structure
interaction which couples the solid and fluid fields and solves the coupled governing
equations. This method is much real than the first one but takes much time. There are
different methods for measuring of the cardiac output including catheterization, MRI,
Ultrasound, and Angiography. All need expensive equipment and some are invasive.
The non invasive techniques of cardiac output calculation have been investigated by
many researchers [ 1,2,3,4,5].
The purpose of this study was to investigate the feasibility
and accuracy of a two-dimensional aortic valve model which is used to study the
performance of the valve in different cardiac outputs and stroke volumes. The numerical
method has been used to model the valve performance based on fluid structure
interaction methodology.
1 Department of Biomechanics, Science and Research Branch, Islamic Azad University,Tehran, Iran.
2 Department of Mechanical Engineering, Iran University of Science and Technology, Tehran, Iran.
3 Department of Biomedical Engineering, Amirkabir University, Tehran, Iran
4 Research Scientist, School of Mechanical Engineering, University of Birmingham, UK
5 Department of cardiovascular Imaging,Shaheed Rajaei cardiovascular ,Medical and research
center,Tehran University of Medical Science,Tehran,Iran
.