Numerical modelling of cardiovascular flows: From in vitro systems to animal models
Author(s)
Van Doormaal, Mark
Type
Thesis
Abstract
Animal models and in vitro endothelial cell culture devices are used extensively to understand the impacts of hemodynamics (including wall shear stress and mass transfer rates) on endothelial cell physiology and atherogenesis. The purpose of this thesis was to use numerical methods to simulate fluid flow and mass transfer phenomenon in endothelial cell culture devices and the mouse aortic arch in order to better understand endothelial cell physiology and atherogenesis.
The design of endothelial cell culture devices that seek to determine the separate roles of abnormal wall shear stress and abnormal mass transfer rates is complicated because areas of "abnormal" mass transfer and "abnormal" wall shear stress tend to co-localize. Therefore, we used numerical methods and design optimization techniques to design two endothelial cell culture devices that are capable of separating areas of low wall shear stress from areas of low wall mass transfer. This resulted in the successful design optimization of one device with a helical geometry and a second device consisting of axial baffles in a tube.
In addition to in vitro endothelial cell culture, mouse models of atherosclerosis are often used to investigate endothelial cell physiology. However, the wall shear stress patterns in the aortic arch of the mouse have not been determined using subject-specific aortic root velocity boundary conditions and aortic arch geometry. Using aortic root velocity profiles as measured via MRI and aortic arch geometry measured via CT scan of a corrosion cast of the arch, we determined the subject-specific wall shear stress patterns in the aortic arch of the mouse.
We found low levels of wall shear stress in both low- and high- probability areas of atherosclerotic lesion formation. We also found that a mouse-averaged aortic root velocity field can accurately substitute for a subject-specific aortic root velocity field if needed.
The design of endothelial cell culture devices that seek to determine the separate roles of abnormal wall shear stress and abnormal mass transfer rates is complicated because areas of "abnormal" mass transfer and "abnormal" wall shear stress tend to co-localize. Therefore, we used numerical methods and design optimization techniques to design two endothelial cell culture devices that are capable of separating areas of low wall shear stress from areas of low wall mass transfer. This resulted in the successful design optimization of one device with a helical geometry and a second device consisting of axial baffles in a tube.
In addition to in vitro endothelial cell culture, mouse models of atherosclerosis are often used to investigate endothelial cell physiology. However, the wall shear stress patterns in the aortic arch of the mouse have not been determined using subject-specific aortic root velocity boundary conditions and aortic arch geometry. Using aortic root velocity profiles as measured via MRI and aortic arch geometry measured via CT scan of a corrosion cast of the arch, we determined the subject-specific wall shear stress patterns in the aortic arch of the mouse.
We found low levels of wall shear stress in both low- and high- probability areas of atherosclerotic lesion formation. We also found that a mouse-averaged aortic root velocity field can accurately substitute for a subject-specific aortic root velocity field if needed.
Date Issued
2010
Date Awarded
2010-11
Copyright Statement
Attribution NoDerivatives 4.0 International Licence (CC BY-ND)
Advisor
Ethier, Ross
Creator
Van Doormaal, Mark
Publisher Department
Bioengineering
Publisher Institution
Imperial College London
Qualification Level
Doctoral
Qualification Name
Doctor of Philosophy (PhD)