Arterial geometry, flow pattern, wall shear and mass transport: potential physiological significance

Area of Science:

• Biomedical Engineering
• Fluid Dynamics
• Cardiovascular Research

Background:

• Intimal hyperplasia (IH) and atherosclerosis are prevalent vascular diseases.
• These conditions often affect regions with low wall shear stress (WSS).
• Previous experiments indicated reduced IH in helically stented arteries.

Purpose of the Study:

• To numerically model blood flow in straight and helically stented common carotid arteries.
• To understand the mechanisms behind reduced intimal hyperplasia observed in helical stenting.
• To investigate the roles of flow pulsatility and vessel three-dimensionality in vascular health.

Main Methods:

• Numerical simulations of steady and unsteady blood flow.
• Analysis of flow patterns, Dean vortices, oxygen flux, and wall shear stress (WSS).
• Modeling of common carotid artery blood flow dynamics.

Main Results:

• Helical stenting combined with flow pulsatility created a sweeping motion of Dean vortices.
• This motion reduced extreme oxygen flux and WSS at the vessel wall.
• Increased waveform amplitude elevated WSS and oxygen flux; increased frequency primarily increased WSS.

Conclusions:

• Vessel three-dimensionality and flow pulsatility offer protective roles against intimal hyperplasia and atherosclerosis.
• Helical stenting may be a beneficial strategy for reducing vascular disease progression.
• Flow waveform parameters significantly influence hemodynamic forces relevant to vascular health.