The relationship between wall shear stress distributions and intimal thickening in the human abdominal aorta.
OBJECTIVE
The goal of this work was to determine wall shear stress (WSS) patterns in the human abdominal aorta and to compare these patterns to measurements of intimal thickness (IT) from autopsy samples.


METHODS
The WSS was experimentally measured using the laser photochromic dye tracer technique in an anatomically faithful in vitro model based on CT scans of the abdominal aorta in a healthy 35-year-old subject. IT was quantified as a function of circumferential and axial position using light microscopy in ten human autopsy specimens.


RESULTS
The histomorphometric analysis suggests that IT increases with age and that the distribution of intimal thickening changes with age. The lowest WSS in the flow model was found on the posterior wall inferior to the inferior mesenteric artery, and coincided with the region of most prominent IT in the autopsy samples. Local geometrical features in the flow model, such as the expansion at the inferior mesenteric artery (common in younger individuals), strongly influenced WSS patterns. The WSS was found to correlate negatively with IT (r2 = 0.3099; P = 0.0047).


CONCLUSIONS
Low WSS in the abdominal aorta is co-localized with IT and may be related to atherogenesis. Also, rates of IT in the abdominal aorta are possibly influenced by age-related geometrical changes.
Bonert
Michael
M
Department of Mechanical and Industrial Engineering, University of Toronto, Canada. michael.bonert@utoronto.ca
Leask
Richard L
RL
Butany
Jagdish
J
Ethier
C Ross
CR
Myers
Jerry G
JG
Johnston
K Wayne
KW
Ojha
Matadial
M
D000328:Adult; D000375:Aging / Q000473:pathology* / Q000502:physiology; D001012:Aorta, Abdominal / Q000000981:diagnostic imaging* / Q000473:pathology / Q000503:physiopathology*; D001344:Autopsy; D003198:Computer Simulation; D005260:Female; D006439:Hemodynamics; D006801:Humans; D008297:Male; D008875:Middle Aged; D008955:Models, Cardiovascular; D011859:Radiography; D012016:Reference Values; D013314:Stress, Mechanical; D017539:Tunica Intima / Q000000981:diagnostic imaging* / Q000473:pathology