Atherosclerosis risk assessment in human carotid artery with variation in sinus length: a numerical approach

Area of Science:

• Biomedical Engineering
• Cardiovascular Physiology
• Fluid Dynamics

Background:

• Cardiovascular diseases, particularly stroke, are a growing global health concern.
• Stroke is often caused by atherosclerotic plaques in the carotid artery, specifically near the common carotid artery (CCA) bifurcation.
• The carotid sinus, a dilated region in the internal carotid artery (ICA), influences blood flow regulation, and its dimensions vary, impacting hemodynamics.

Purpose of the Study:

• To investigate the impact of varying carotid sinus length on hemodynamics.
• To analyze biomechanical risk factors for atherosclerosis development.
• To understand the local and global effects of sinus dimensions on carotid artery blood flow.

Main Methods:

• A 3D computational fluid dynamics (CFD) model was employed.
• Pulsatile flow velocity profiles were imposed using a user-defined function (UDF).
• Carotid sinus length was systematically varied to assess hemodynamic changes and atherosclerosis risk parameters.

Main Results:

• Increased sinus length shifted recirculation zones towards the outer wall (OW) with greater strength.
• Lower blood flow velocities and increased recirculation were observed near the OW.
• Significantly decreased x-wall shear stress (x-WSS) and time-averaged wall shear stress (TAWSS) were noted on the OW of longer sinuses.

Conclusions:

• Longer carotid sinus lengths are associated with reduced WSS and altered flow patterns.
• Higher oscillatory shear index (OSI) and relative residence time (RRT) in longer sinuses indicate increased atherosclerosis risk.
• Increased carotid sinus length is a significant risk factor for atherosclerotic plaque development.