Flow patterns in the human carotid artery bifurcation.

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.