Velocity and Wall Shear Stress Patterns in the Human Right Coronary Artery

1999 ◽  
Vol 121 (4) ◽  
pp. 370-375 ◽  
Author(s):  
A. Kirpalani ◽  
H. Park ◽  
J. Butany ◽  
K. W. Johnston ◽  
M. Ojha
Keyword(s):  
Shear Stress ◽  
Coronary Artery ◽  
Wall Shear Stress ◽  
Right Coronary Artery ◽  
Proximal Region ◽  
Proximal Segment ◽  
Shear Stresses ◽  
Human Right ◽  
Wall Shear ◽  
Stress Patterns

Blood flow dynamics in the human right coronary artery have not been adequately quantified despite the clinical significance of coronary atherosclerosis. In this study, a technique was developed to construct a rigid flow model from a cast of a human right coronary artery. A laser photochromic method was used to characterize the velocity and wall shear stress patterns. The flow conditions include steady flow at Reynolds numbers of 500 and 1000 as well as unsteady flow with Womersley parameter and peak Reynolds number of 1.82 and 750, respectively. Characterization of the three-dimensional geometry of the artery revealed that the largest spatial variation in curvature occurred within the almost branch-free proximal region, with the greatest curvature existing along the acute margin of the heart. In the proximal segment, high shear stresses were observed on the outer wall and lower, but not negative, stresses along the inner wall. Low shear stress on the inner wall may be related to the preferential localization of atherosclerosis in the proximal segment of the right coronary artery. However, it is possible that the large difference between the outer and inner wall shear stresses may also be involved.

scholarly journals Intimal Thickness Is not Associated With Wall Shear Stress Patterns in the Human Right Coronary Artery

2004 ◽  
Vol 24 (12) ◽  
pp. 2408-2413 ◽  
Author(s):  
Anil K. Joshi ◽  
Richard L. Leask ◽  
Jerry G. Myers ◽  
Matadial Ojha ◽  
Jagdish Butany ◽  
...  
Keyword(s):  
Shear Stress ◽  
Coronary Artery ◽  
Wall Shear Stress ◽  
Right Coronary Artery ◽  
Human Right ◽  
Intimal Thickness ◽  
Wall Shear ◽  
Stress Patterns

A Study on the Compliance of a Right Coronary Artery and Its Impact on Wall Shear Stress

2008 ◽  
Vol 130 (4) ◽  
Author(s):  
Dehong Zeng ◽  
Evangelos Boutsianis ◽  
Marc Ammann ◽  
Kevin Boomsma ◽  
Simon Wildermuth ◽  
...  
Keyword(s):  
Shear Stress ◽  
Coronary Artery ◽  
Wall Shear Stress ◽  
Right Coronary Artery ◽  
Imaging Techniques ◽  
Time History ◽  
Distal Region ◽  
Proximal Region ◽  
Phase Changes ◽  
Wall Shear

A computational model incorporating physiological motion and uniform transient wall deformation of a branchless right coronary artery (RCA) was developed to assess the influence of artery compliance on wall shear stress (WSS). Arterial geometry and deformation were derived from modern medical imaging techniques, whereas the blood flow was solved numerically employing a moving-grid approach using a well-validated in-house finite element code. The simulation results indicate that artery compliance affects the WSS in the RCA heterogeneously, with the distal region mostly experiencing these effects. Under physiological inflow conditions, coronary compliance contributed to phase changes in the WSS time history, without affecting the temporal gradient of the local WSS nor the bounds of the WSS magnitude. Compliance does not cause considerable changes to the topology of WSS vector patterns nor to the localization of WSS minima along the RCA. We conclude that compliance is not an important factor affecting local hemodynamics in the proximal region of the RCA while the influence of compliance in the distal region needs to be evaluated in conjunction with the outflow to the myocardium through the major branches of the RCA.

scholarly journals Numerical Simulation of Dispersed Particle-Blood Flow in the Stenosed Coronary Arteries

2018 ◽  
Vol 2018 ◽  
pp. 1-16 ◽  
Author(s):  
Mongkol Kaewbumrung ◽  
Somsak Orankitjaroen ◽  
Pichit Boonkrong ◽  
Buraskorn Nuntadilok ◽  
Benchawan Wiwatanapataphee
Keyword(s):  
Numerical Simulation ◽  
Blood Flow ◽  
Shear Stress ◽  
Coronary Artery ◽  
Pressure Drop ◽  
Wall Shear Stress ◽  
Stokes Equations ◽  
Spherical Shape ◽  
Shear Stresses ◽  
Wall Shear

A mathematical model of dispersed bioparticle-blood flow through the stenosed coronary artery under the pulsatile boundary conditions is proposed. Blood is assumed to be an incompressible non-Newtonian fluid and its flow is considered as turbulence described by the Reynolds-averaged Navier-Stokes equations. Bioparticles are assumed to be spherical shape with the same density as blood, and their translation and rotational motions are governed by Newtonian equations. Impact of particle movement on the blood velocity, the pressure distribution, and the wall shear stress distribution in three different severity degrees of stenosis including 25%, 50%, and 75% are investigated through the numerical simulation using ANSYS 18.2. Increasing degree of stenosis severity results in higher values of the pressure drop and wall shear stresses. The higher level of bioparticle motion directly varies with the pressure drop and wall shear stress. The area of coronary artery with higher density of bioparticles also presents the higher wall shear stress.

Investigation of the Effects of Dynamic Change in Curvature and Torsion on Pulsatile Flow in a Helical Tube

2012 ◽  
Vol 134 (7) ◽  
Author(s):  
N. K. C. Selvarasu ◽  
Danesh K. Tafti
Keyword(s):  
Shear Stress ◽  
Coronary Artery ◽  
Wall Shear Stress ◽  
Secondary Flow ◽  
Pulsatile Flow ◽  
Flow Patterns ◽  
Shear Stresses ◽  
Wall Shear ◽  
Vorticity Flux ◽  
Curvature And Torsion

Cardiovascular diseases are the number one cause of death in the world, making the understanding of hemodynamics and the development of treatment options imperative. The effect of motion of the coronary artery due to the motion of the myocardium is not extensively studied. In this work, we focus our investigation on the localized hemodynamic effects of dynamic changes in curvature and torsion. It is our objective to understand and reveal the mechanism by which changes in curvature and torsion contribute towards the observed wall shear stress distribution. Such adverse hemodynamic conditions could have an effect on circumferential intimal thickening. Three-dimensional spatiotemporally resolved computational fluid dynamics (CFD) simulations of pulsatile flow with moving wall boundaries were carried out for a simplified coronary artery with physiologically relevant flow parameters. A model with stationary walls is used as the baseline control case. In order to study the effect of curvature and torsion variation on local hemodynamics, this baseline model is compared to models where the curvature, torsion, and both curvature and torsion change. The simulations provided detailed information regarding the secondary flow dynamics. The results suggest that changes in curvature and torsion cause critical changes in local hemodynamics, namely, altering the local pressure and velocity gradients and secondary flow patterns. The wall shear stress (WSS) varies by a maximum of 22% when the curvature changes, by 3% when the torsion changes, and by 26% when both the curvature and torsion change. The oscillatory shear stress (OSI) varies by a maximum of 24% when the curvature changes, by 4% when the torsion changes, and by 28% when both the curvature and torsion change. We demonstrate that these changes are attributed to the physical mechanism associating the secondary flow patterns to the production of vorticity (vorticity flux) due to the wall movement. The secondary flow patterns and augmented vorticity flux affect the wall shear stresses. As a result, this work reveals how changes in curvature and torsion act to modify the near wall hemodynamics of arteries.

Branch Flow Effects in the Human Right Coronary Artery Trunk

2000 ◽  
Author(s):  
Jerry G. Myers ◽  
M. Ojha ◽  
K. Wayne Johnston ◽  
C. Ross Ethier
Keyword(s):  
Shear Stress ◽  
Coronary Artery ◽  
Wall Shear Stress ◽  
Atherosclerotic Plaque ◽  
Right Coronary Artery ◽  
Realistic Model ◽  
Patient Specific ◽  
Human Right ◽  
Geometric Characteristics ◽  
Flow Effects

Abstract Formation of atherosclerotic plaque in the human right coronary artery (RCA) has, in part, been linked to local hemodynamic factors (Ojha et al., 2000). Thus, there is considerable motivation to accurately characterize hemodynamic patterns in the RCA. Patient-specific geometric characteristics, such as curvature and arterial calibre, have been shown to significantly affect velocity and wall shear stress (WSS) patterns within the RCA trunk (Myers et al., 2000). However it is unclear how flow into arterial branches influences these hemodynamic patterns. In investigating this factor, we computed velocity and WSS distributions in a realistic model of a human right coronary artery (RCA) that included four branches.

Numerical Simulation of Blood-Wall Albumin Transport in a Realistic Human Right Coronary Artery

2007 ◽  
Author(s):  
Nanfeng Sun ◽  
Ryo Torii ◽  
Nigel B. Wood ◽  
Andrew Wright ◽  
Alun D. Hughes ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Shear Stress ◽  
Coronary Artery ◽  
Endothelial Dysfunction ◽  
Wall Shear Stress ◽  
Right Coronary Artery ◽  
Flow Conditions ◽  
Human Right ◽  
Wall Model ◽  
Flow Pulsatility

Low wall shear stress (WSS) is commonly implicated in endothelial dysfunction and atherogenesis. The accumulation of macromolecules is also considered as an important factor contributing to the development of atherosclerosis. In the present study a fluid-wall model, incorporating shear-dependent endothelial transport properties, was developed and used to study the transport of albumin from blood to and within the wall in a realistic human right coronary artery (RCA). Numerical simulations were performed at both steady and pulsatile flow conditions, and results were compared to evaluate the effect of flow pulsatility.

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