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.

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

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.

scholarly journals Elevated oxidative stress and endothelial dysfunction in right coronary artery of right ventricular hypertrophy

2011 ◽  
Vol 110 (6) ◽  
pp. 1674-1681 ◽  
Author(s):  
Xiao Lu ◽  
Charles Q. Dang ◽  
Xiaomei Guo ◽  
Sabee Molloi ◽  
Cynthia D. Wassall ◽  
...  
Keyword(s):  
Blood Flow ◽  
Shear Stress ◽  
Coronary Artery ◽  
Endothelial Dysfunction ◽  
Wall Shear Stress ◽  
Endothelial Function ◽  
Right Ventricular ◽  
Right Coronary Artery ◽  
Ventricular Hypertrophy ◽  
Basal Tone

Remodeling of right coronary artery (RCA) occurs during right ventricular hypertrophy (RVH) induced by banding of the pulmonary artery (PA). The effect of RVH on RCA endothelial function and reactive oxygen species (ROS) in vessel wall remains unclear. A swine RVH model ( n = 12 pigs) induced by PA banding was used to study RCA endothelial function and ROS level. To obtain longitudinal coronary hemodynamic and geometric data, digital subtraction angiography was used during the progression of RVH. Blood flow in the RCA increased by 82% and lumen diameter of RCA increased by 22% over a 4-wk period of RVH. The increase in blood flow and the commensurate increase in diameter resulted in a constant wall shear stress in RCA throughout the RVH period. ROS was elevated by ∼100% in RCA after 4 wk of PA banding. The expressions of p47phox, NADPH oxidase (NOX1, NOX2, and NOX4) were upregulated in the range of 20–300% in RCA of RVH. The endothelial function was compromised in RCA of RVH as attributed to insufficient endothelial nitric oxide synthase cofactor tetrahydrobiopterin. In vivo angiographic analysis suggests an increased basal tone in the RCA during RVH. In conclusion, stretch due to outward remodeling of RCA during RVH (at constant wall shear stress), similar to vessel stretch in hypertension, appears to induce ROS elevation, endothelial dysfunction, and an increase in basal tone.

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 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.

scholarly journals Coronary endothelial dysfunction is associated with a reduction in coronary artery compliance and an increase in wall shear stress

Heart ◽  
2010 ◽  
Vol 96 (10) ◽  
pp. 773-778 ◽  
Author(s):  
T. Takumi ◽  
E. H. Yang ◽  
V. Mathew ◽  
C. S. Rihal ◽  
R. Gulati ◽  
...  
Keyword(s):  
Shear Stress ◽  
Coronary Artery ◽  
Endothelial Dysfunction ◽  
Wall Shear Stress ◽  
Wall Shear ◽  
Coronary Endothelial Dysfunction

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.

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