Related Experiment Videos
Factors influencing blood flow patterns in the human right coronary artery
1Department of Mechanical and Industrial Engineering, University of Toronto, Ontario, Canada.
Insights
Local artery geometry, not flow patterns, significantly impacts blood flow and wall shear stress in the right coronary artery (RCA). Patient-specific models are crucial for understanding atherogenesis linked to hemodynamics.
Area of Science:
- Cardiovascular Science
- Biomedical Engineering
- Fluid Dynamics
Background:
- Atherogenesis, the development of atherosclerotic plaques, is associated with local hemodynamic factors.
- Wall shear stress (WSS) is a critical hemodynamic factor implicated in the initiation and progression of atherosclerosis.
- The human right coronary artery (RCA) is a common site for atherosclerotic lesion development.
Purpose of the Study:
- To investigate velocity and WSS patterns within a human RCA model.
- To evaluate the influence of flow waveform and inlet velocity profile on hemodynamics in different arterial regions.
- To determine the dominant factors influencing RCA hemodynamics relevant to atherogenesis.
Main Methods:
- Utilized the finite-element method to compute velocity and WSS patterns.
- Employed a rigid, anatomically realistic human RCA model.
- Conducted steady and pulsatile flow simulations with varying inlet velocity profiles and flow waveforms.
Main Results:
- Dean-like secondary flow features were observed, highly sensitive to local RCA curvature.
- Local 3D curvature induced significant variations in WSS along the artery sidewalls.
- Inlet flow conditions (waveform and velocity profile) had minimal impact on overall velocity and WSS patterns.
- Pulsatile flow simulations showed similar cycle-average WSS distributions irrespective of flow conditions.
- Low oscillatory shear index was primarily due to flow reversal, not flow separation.
Conclusions:
- Geometric factors, especially local 3D curvature, are the primary determinants of RCA hemodynamics.
- Hemodynamic studies investigating atherogenesis should incorporate patient-specific RCA geometry.
- Understanding the interplay between geometry and hemodynamics is vital for predicting atherosclerotic lesion development.
Abstract:
Evidence suggests that atherogenesis is linked to local hemodynamic factors such as wall shear stress. We investigated the velocity and wall shear stress patterns within a human right coronary artery (RCA), an important site of atherosclerotic lesion development. Emphasis was placed on evaluating the effect of flow waveform and inlet flow velocity profile on the hemodynamics in the proximal, medial, and distal arterial regions. Using the finite-element method, velocity and wall shear stress patterns in a rigid, anatomically realistic model of a human RCA were computed. Steady flow simulations (ReD=500) were performed with three different inlet velocity profiles; pulsatile flow simulations utilized two different flow waveforms (both with Womersley parameter=1.82, mean ReD=233), as well as two of the three inlet profiles. Velocity profiles showed Dean-like secondary flow features that were remarkably sensitive to the local curvature of the RCA model. Particularly noteworthy was the "rotation" of these Dean-like profiles, which produced large local variations in wall shear stress along the sidewalls of the RCA model. Changes in the inlet velocity profiles did not produce significant changes in the arterial velocity and wall shear stress patterns. Pulsatile flow simulations exhibited remarkably similar cycle-average wall shear stress distributions regardless of waveform and inlet velocity profile. The oscillatory shear index was very small and was attributed to flow reversal in the waveform, rather than separation. Cumulatively, these results illustrate that geometric effects (particularly local three-dimensional curvature) dominate RCA hemodynamics, implying that studies attempting to link hemodynamics with atherogenesis should replicate the patient-specific RCA geometry.