Effect of plaque micro-watershed changes on carotid atherosclerosis

Area of Science:

• Cardiovascular Science
• Biomedical Engineering
• Fluid Dynamics

Background:

• Atherosclerotic lesions in carotid arteries pose significant risks for stroke.
• Understanding the hemodynamic forces driving plaque progression is crucial for effective treatment strategies.

Purpose of the Study:

• To investigate the mechanisms of plaque growth by analyzing hemodynamic parameter variations in carotid arteries.
• To compare blood flow dynamics before and after atherosclerotic lesion development.

Main Methods:

• Enrolled 25 patients with common carotid artery stenosis and 25 with tandem carotid artery stenosis.
• Constructed 3D models of carotid arteries before and after lesions for two patients.
• Utilized computational fluid dynamics (CFD) for unsteady, non-Newtonian fluid simulations to analyze blood flow micro-environment changes.

Main Results:

• Vortex regions form at carotid artery bifurcations during systole and expand during diastole.
• Low shear stress zones develop at the shoulder of initial plaques, promoting growth.
• Wall shear stress patterns show high central and low upper shoulder values in stenotic plaques, with critical differences in tandem stenosis.

Conclusions:

• Blood flow dynamics vary significantly throughout the cardiac cycle and within local lesions.
• Carotid artery stenosis, both common and tandem, shows lesion development susceptibility at initial plaque shoulders.
• Altered micro-flow characteristics precede and follow carotid artery disease, with plaque growth location linked to restenosis and rupture risk.