Atherosclerosis develops non-uniformly within the arterial system and the distribution
of lesions has been observed to change with age. This thesis investigates the
concept that the patchiness of the disease is related to local variations in blood flow.
Based on the insights from a systematic literature review, a novel study was
designed to analyse the relation between haemodynamic factors and age-dependent
atherogenesis in the thoracic aorta of rabbits. Arterial geometries were reconstructed
by micro-Computed Tomography of vascular corrosion casts, with particular attention
to the anatomical accuracy of the dataset. Blood flow was simulated in these
geometries using a spectral/hp element method. Distributions of traditional shear-related
metrics were calculated and both qualitatively and quantitatively compared
to maps of lesion prevalence. In addition, a time-averaged transverse wall shear
stress was introduced.
A geometric analysis of the dataset of rabbit thoracic aortas revealed a significant
change with age in the degree of aortic taper. The geometric changes could
explain age-related differences in flow characteristics, in particular in the extent of
Dean-type vortical structures into the descending aorta and the strength of a dorsal
streak of high shear. The comparative analysis of shear and lesion distributions
did not unequivocally support the theory that lesions occur in regions of low shear.
The novel haemodynamic metric, in combination with current metrics, enabled an
improved identification of zones of multi-directional disturbed flow.
In conclusion, this thesis adds to the understanding of the relation between blood flow and early atherosclerosis, and provides tools for use in future studies.