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Flow through a Complaint Stenotic Artery: A Parametric Evaluation.
Final rept. Dec 91-Mar 93,
ARMSTRONG LAB BROOKS AFB TX OCCUPATIONAL AND ENVIRONMENTAL HEALTH DIRECTORATE
Pagination or Media Count:
Hardening of the arteries from atherosclerosis can produce high grade stenoses which lead to morbid symptoms of heart attack and stroke. Blood flow through the stenosis produces a low pressure zone at the throat which may cause the elastic artery to collapse. A one-dimensional model of collapsible tube flow through a smooth1 compliant stenoses was developed to evaluate the relative effects of several physiologic parameters. These variables included changes in percent stenosis, distal resistance, viscous separation losses, unsteady effects, stiffness variations, and non-linear tube law shapes. The range of variation attempted to bracket the conditions expected for diseased carotid and coronary arteries. The time-dependent equations were solved using MacCormacks method. Collapsed flow was more likely to be achieved with soft stenoses greater than 80 by diameter, low downstream resistances, and high external pressures. Collapsed flow was less likely to occur with stiff stenoses of less than 80 dia with a high distal resistance, large viscous losses, and a low external pressure. Pulsatile conditions resulted in situations where flow could alternate between supercritical and subcritical flow during the cycle. The results demonstrate that collapse of high grade stenotic arteries can occur under physiological conditions.
APPROVED FOR PUBLIC RELEASE