Modeling the Effect of Red Blood Cells Deformability on Blood Flow Conditions in Human Carotid Artery Bifurcation

2016 ◽  
Vol 139 (1) ◽  
Author(s):  
Janez Urevc ◽  
Iztok Žun ◽  
Milan Brumen ◽  
Boris Štok
Keyword(s):  
Blood Flow ◽  
Carotid Artery ◽  
Red Blood Cells ◽  
Blood Viscosity ◽  
Blood Cells ◽  
Viscosity Model ◽  
Flow Conditions ◽  
Geometrical Properties ◽  
Carotid Artery Bifurcation ◽  
Human Carotid

The purpose of this work is to predict the effect of impaired red blood cells (RBCs) deformability on blood flow conditions in human carotid artery bifurcation. First, a blood viscosity model is developed that predicts the steady-state blood viscosity as a function of shear rate, plasma viscosity, and mechanical (and geometrical) properties of RBC's. Viscosity model is developed by modifying the well-known Krieger and Dougherty equation for monodisperse suspensions by using the dimensional analysis approach. With the approach, we manage to account for the microscopic properties of RBC's, such as their deformability, in the macroscopic behavior of blood via blood viscosity. In the second part of the paper, the deduced viscosity model is used to numerically predict blood flow conditions in human carotid artery bifurcation. Simulations are performed for different values of RBC's deformability and analyzed by investigating parameters, such as the temporal mean wall shear stress (WSS), oscillatory shear index (OSI), and mean temporal gradient of WSS. The analyses show that the decrease of RBC's deformability decrease the regions of low WSS (i.e., sites known to be prevalent at atherosclerosis-prone regions); increase, in average, the value of WSS along the artery; and decrease the areas of high OSI. These observations provide an insight into the influence of blood's microscopic properties, such as the deformability of RBC's, on hemodynamics in larger arteries and their influence on parameters that are known to play a role in the initiation and progression of atherosclerosis.

scholarly journals Deformation and dynamics of red blood cells in flow through cylindrical microchannels

Soft Matter ◽  
2014 ◽  
Vol 10 (24) ◽  
pp. 4258-4267 ◽  
Author(s):  
Dmitry A. Fedosov ◽  
Matti Peltomäki ◽  
Gerhard Gompper
Keyword(s):  
Blood Flow ◽  
Red Blood Cells ◽  
Blood Cells ◽  
Flow Resistance ◽  
Flow Conditions ◽  
Hydrodynamic Simulations ◽  
Wide Range ◽  
Flow Through ◽  
Cell Partitioning

The behavior of red blood cells (RBCs) in microvessels plays an important role in blood flow resistance and in the cell partitioning within a microcirculatory network. We employ mesoscopic hydrodynamic simulations to study the behavior and deformation of single RBCs in microchannels yielding the construction of diagrams of RBC shapes for a wide range of flow conditions.

Plasma viscosity and cerebral blood flow

2000 ◽  
Vol 279 (4) ◽  
pp. H1949-H1954 ◽  
Author(s):  
Yoshinobu Tomiyama ◽  
Johnny E. Brian ◽  
Michael M. Todd
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Blood Viscosity ◽  
Blood Cells ◽  
Exchange Transfusion ◽  
Ringer Solution ◽  
Plasma Viscosity ◽  
High Flow ◽  
Flow Conditions ◽  
Whole Blood Viscosity

We hypothesized that the response of cerebral blood flow (CBF) to changing viscosity would be dependent on “baseline” CBF, with a greater influence of viscosity during high-flow conditions. Plasma viscosity was adjusted to 1.0 or 3.0 cP in rats by exchange transfusion with red blood cells diluted in lactated Ringer solution or with dextran. Cortical CBF was measured by H2 clearance. Two groups of animals remained normoxic and normocarbic and served as controls. Other groups were made anemic, hypercapnic, or hypoxic to increase CBF. Under baseline conditions before intervention, CBF did not differ between groups and averaged 49.4 ± 10.2 ml · 100 g−1 · min−1 (±SD). In control animals, changing plasma viscosity to 1.0 or 3.0 cP resulted in CBF of 55.9 ± 8.6 and 42.5 ± 12.7 ml · 100 g−1 · min−1, respectively (not significant). During hemodilution, hypercapnia, and hypoxia with a plasma viscosity of 1.0 cP, CBF varied from 98 to 115 ml · 100 g−1 · min−1. When plasma viscosity was 3.0 cP during hemodilution, hypercapnia, and hypoxia, CBF ranged from 56 to 58 ml · 100 g−1 · min−1 and was significantly reduced in each case ( P < 0.05). These results support the hypothesis that viscosity has a greater role in regulation of CBF when CBF is increased. In addition, because CBF more closely followed changes in plasma viscosity (rather than whole blood viscosity), we believe that plasma viscosity may be the more important factor in controlling CBF.

scholarly journals Effects of Hematocrit on Blood Flow Through A Stenosed Human Carotid Artery

2020 ◽  
pp. 2106-2114
Author(s):  
Sefiu Onitilo ◽  
Mustapha Usman ◽  
Deborah Daniel
Keyword(s):  
Blood Flow ◽  
Shear Stress ◽  
Wall Shear Stress ◽  
Red Blood Cells ◽  
Blood Cells ◽  
Carotid Arteries ◽  
Governing Equations ◽  
Flow Through ◽  
Wall Shear ◽  
Human Carotid

In this paper, the effects of hematocrit of red blood cells on blood flow through a stenosed human carotid artery was considered by taking blood as a Newtonian fluid. The governing equations on blood flow were derived. The mathematical content involved in the equations are the variables of interest such as number of stenosis , percentage of hematocrit  of red blood cells in the blood, flow rate, wall shear stress, and viscosity of the blood. Guided by medical data collected on the constraint of blood flow in stenosed human carotid arteries, the governing equations were used to check the effects of pressure gradient, wall shear stress, velocity, and volumetric flow rate of blood in the human carotid arteries. Also, the one-dimensional equation for the steady and axially symmetric flow of blood through an artery was transformed using Einstein’s coefficient of viscosity and hematocrit of red blood cells with the help of the boundary conditions. The effects of hematocrit on the blood flow characteristics are shown graphically and discussed briefly. It was discovered that the resistance increases as the level of hematocrit increases. Also, the wall shear stress decreases with the increase in the hematocrit level of the red blood cells. 

scholarly journals Four-Dimensional Flow Magnetic Resonance Imaging for Assessment of Velocity Magnitudes and Flow Patterns in The Human Carotid Artery Bifurcation: Comparison with Computational Fluid Dynamics

Diagnostics ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 223 ◽  
Author(s):  
Minh Tri Ngo ◽  
Chul In Kim ◽  
Jinmu Jung ◽  
Gyung Ho Chung ◽  
Dong Hwan Lee ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Fluid Dynamics ◽  
Blood Flow ◽  
Carotid Artery ◽  
Resonance Imaging ◽  
4D Flow Mri ◽  
4D Flow ◽  
Carotid Artery Bifurcation ◽  
Flow Mri ◽  
Human Carotid

Purpose: Knowledge of the hemodynamics in the vascular system is important to understand and treat vascular pathology. The present study aimed to evaluate the hemodynamics in the human carotid artery bifurcation measured by four-dimensional (4D) flow magnetic resonance imaging (MRI) as compared to computational fluid dynamics (CFD). Methods: This protocol used MRI data of 12 healthy volunteers for the 3D vascular models and 4D flow MRI measurements for the boundary conditions in CFD simulation. We compared the velocities measured at the carotid bifurcation and the 3D velocity streamlines of the carotid arteries obtained by these two methods. Results: There was a good agreement for both maximum and minimum velocity values between the 2 methods for velocity magnitude at the bifurcation plane. However, on the 3D blood flow visualization, secondary flows, and recirculation regions are of poorer quality when visualized through the 4D flow MRI. Conclusion: 4D flow MRI and CFD show reasonable agreement in demonstrated velocity magnitudes at the carotid artery bifurcation. However, the visualization of blood flow at the recirculation regions and the assessment of secondary flow characteristics should be enhanced for the use of 4D flow MRI in clinical situations.

scholarly journals Mathematical Models for Some Aspects of Blood Microcirculation

Symmetry ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 1020
Author(s):  
Angiolo Farina ◽  
Antonio Fasano ◽  
Fabio Rosso
Keyword(s):  
Blood Flow ◽  
Mathematical Models ◽  
Red Blood Cells ◽  
Blood Cells ◽  
Blood Rheology ◽  
Small Class ◽  
Small Vessels ◽  
Blood Microcirculation ◽  
Peculiar Behavior

Blood rheology is a challenging subject owing to the fact that blood is a mixture of a fluid (plasma) and of cells, among which red blood cells make about 50% of the total volume. It is precisely this circumstance that originates the peculiar behavior of blood flow in small vessels (i.e., roughly speaking, vessel with a diameter less than half a millimeter). In this class we find arteriolas, venules, and capillaries. The phenomena taking place in microcirculation are very important in supporting life. Everybody knows the importance of blood filtration in kidneys, but other phenomena, of not less importance, are known only to a small class of physicians. Overviewing such subjects reveals the fascinating complexity of microcirculation.

Multiscale Modeling of Flow Induced Thrombogenicity Using Dissipative Particle Dynamics and Molecular Dynamics

2013 ◽  
Author(s):  
Danny Bluestein ◽  
João S. Soares ◽  
Peng Zhang ◽  
Chao Gao ◽  
Seetha Pothapragada ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Blood Flow ◽  
Red Blood Cells ◽  
Platelet Activation ◽  
Blood Cells ◽  
Dissipative Particle Dynamics ◽  
Particle Dynamics ◽  
Coagulation Cascade ◽  
Shear Stresses ◽  
Activated Platelets

The coagulation cascade of blood may be initiated by flow induced platelet activation, which prompts clot formation in prosthetic cardiovascular devices and arterial disease processes. While platelet activation may be induced by biochemical agonists, shear stresses arising from pathological flow patterns enhance the propensity of platelets to activate and initiate the intrinsic pathway of coagulation, leading to thrombosis. Upon activation platelets undergo complex biochemical and morphological changes: organelles are centralized, membrane glycoproteins undergo conformational changes, and adhesive pseudopods are extended. Activated platelets polymerize fibrinogen into a fibrin network that enmeshes red blood cells. Activated platelets also cross-talk and aggregate to form thrombi. Current numerical simulations to model this complex process mostly treat blood as a continuum and solve the Navier-Stokes equations governing blood flow, coupled with diffusion-convection-reaction equations. It requires various complex constitutive relations or simplifying assumptions, and is limited to μm level scales. However, molecular mechanisms governing platelet shape change upon activation and their effect on rheological properties can be in the nm level scales. To address this challenge, a multiscale approach which departs from continuum approaches, may offer an effective means to bridge the gap between macroscopic flow and cellular scales. Molecular dynamics (MD) and dissipative particle dynamics (DPD) methods have been employed in recent years to simulate complex processes at the molecular scales, and various viscous fluids at low-to-high Reynolds numbers at mesoscopic scales. Such particle methods possess important properties at the mesoscopic scale: complex fluids with heterogeneous particles can be modeled, allowing the simulation of processes which are otherwise very difficult to solve by continuum approaches. It is becoming a powerful tool for simulating complex blood flow, red blood cells interactions, and platelet-mediated thrombosis involving platelet activation, aggregation, and adhesion.

scholarly journals A Systematic Review for the Design of In Vitro Flow Studies of the Carotid Artery Bifurcation

2019 ◽  
Vol 11 (2) ◽  
pp. 111-127 ◽  
Author(s):  
A. M. Hoving ◽  
E. E. de Vries ◽  
J. Mikhal ◽  
G. J. de Borst ◽  
C. H. Slump
Keyword(s):  
Blood Flow ◽  
Carotid Artery ◽  
Flow Visualization ◽  
Design Process ◽  
Imaging Technique ◽  
Carotid Artery Disease ◽  
Imaging Techniques ◽  
Carotid Artery Bifurcation ◽  
Flow Parameters

Abstract Purpose In vitro blood flow studies in carotid artery bifurcation models may contribute to understanding the influence of hemodynamics on carotid artery disease. However, the design of in vitro blood flow studies involves many steps and selection of imaging techniques, model materials, model design, and flow visualization parameters. Therefore, an overview of the possibilities and guidance for the design process is beneficial for researchers with less experience in flow studies. Methods A systematic search to in vitro flow studies in carotid artery bifurcation models aiming at quantification and detailed flow visualization of blood flow dynamics results in inclusion of 42 articles. Results Four categories of imaging techniques are distinguished: MRI, optical particle image velocimetry (PIV), ultrasound and miscellaneous techniques. Parameters for flow visualization are categorized into velocity, flow, shear-related, turbulent/disordered flow and other parameters. Model materials and design characteristics vary between study type. Conclusions A simplified three-step design process is proposed for better fitting and adequate match with the pertinent research question at hand and as guidance for less experienced flow study researchers. The three consecutive selection steps are: flow parameters, image modality, and model materials and designs. Model materials depend on the chosen imaging technique, whereas choice of flow parameters is independent from imaging technique and is therefore only determined by the goal of the study.

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