Related Experiment Videos
Insights
Blood flow patterns in the carotid artery bifurcation create recirculation zones. These zones influence cell interactions and may contribute to atherosclerosis and thrombosis development.
Area of Science:
- Cardiovascular Science
- Biomedical Engineering
- Fluid Dynamics
Background:
- Atherosclerosis and thrombosis often occur at the carotid artery bifurcation.
- Understanding blood flow dynamics is crucial for elucidating disease origins.
Purpose of the Study:
- To investigate the relationship between blood flow patterns and the development of atherosclerosis and thrombosis.
- To analyze fluid velocity and wall shear rate distributions in the human carotid artery bifurcation.
Main Methods:
- Utilized a postmortem human carotid artery segment for flow studies.
- Employed cinemicrographic techniques to observe flow patterns.
- Analyzed recirculation zone formation and size across various flow conditions.
Main Results:
- A recirculation zone with complex spiral secondary flows was identified in the carotid sinus.
- The recirculation zone's size varied with inflow Reynolds number (Re0) and flow rate ratio (Q1/Q0).
- Zone size increased from 4 mm at Re0=300 to 9 mm at Re0 > 800.
Conclusions:
- A standing recirculation zone exists under physiological conditions in the carotid sinus.
- This zone impacts local mass transfer and blood cell-wall interactions.
- These effects are implicated in the localized incidence of atherosclerosis and thrombosis.
Abstract:
To elucidate the connection between blood flow and the localized genesis and development of atherosclerosis and thrombosis at the human carotid artery bifurcation, detailed studies of the flow patterns and distributions of fluid velocity and wall shear rate in this region were carried out using a transparent segment of the carotid artery, prepared from a human subject postmortem, and cinemicrographic techniques. It was found that a recirculation zone which consisted of a pair of complex spiral secondary flows, symmetrical about the common median plane of the bifurcation, was formed in the carotid sinus over wide ranges of inflow Reynolds numbers, Re0, and flow rate ratios, Q1/Q0 (internal/common). The formation and the size of the recirculation zone were largely dependent on Q1/Q0, as well as on Re0. The size of the recirculation zone increased from approximately 4 mm at Re0 = 300 to a maximum of approximately 9 mm at Re0 greater than 800. The results suggest that, under physiological conditions (Re0 approximately 600, Q1/Q0 approximately 0.7), a standing recirculation zone exists in the carotid sinus, thereby affecting local mass transfer and interactions of blood cells with the vessel wall, which may lead to the incidence of atherosclerosis and thrombosis in this region.