Hemodynamics Numerical Simulation of Stenosis Bifurcation

2015 ◽  
Author(s):  
Krunal Chaudhari ◽  
Hardikkumar Patel
Keyword(s):  
Blood Flow ◽  
Cardiovascular Diseases ◽  
Blood Vessel ◽  
Model Parameters ◽  
Aortic Atherosclerosis ◽  
Structure Interaction ◽  
Favorable Change ◽  
Constant Viscosity ◽  
Blood Density ◽  
Velocity Pressure

The main purpose of this research is to analyze blood flow in various scenarios such as 20%, 50% and 80% blockage in blood vessel due to aortic atherosclerosis. Valuable Information for clinical diagnosis of cardiovascular diseases can be obtained by analyzing the behavior of blood flow and its variations. An idealized numerical model of the human bifurcated aorta is created then simulations of steady blood flow were performed on this model and various parameters have been considered. The model parameters include the blood flow velocity, pressure, wall shear stress (WSS) of vessels, constant blood density and constant viscosity. The data computed from software indicates behavior of blood flow according to changes in physical properties of blood vessel. These results are mostly similar to physiological and pathological results of vessels observed in clinical practice. This study will eventually help to find the Fluid Structure Interaction (FSI) of blood flow and blood vessel which will be bring a favorable change in cardiovascular diseases treatments.

Numerical Simulation of Pulsating Flow over Blood Vessel Robot

2012 ◽  
Vol 591-593 ◽  
pp. 1734-1738
Author(s):  
Chun Yan Huang ◽  
Fan Jiang
Keyword(s):  
Numerical Simulation ◽  
Boundary Condition ◽  
Blood Flow ◽  
Blood Vessel ◽  
Surface Pressure ◽  
Blood Parameters ◽  
Pulsating Flow ◽  
Inlet Velocity ◽  
Blood Density

In order to study the influence of pulsating blood flow to robot and blood vessel, UDF programming of the inlet velocity is defined as the boundary condition, and the model simulate the turbulent blood flow. Moreover, in this situation, this paper analyzes the influence caused by blood parameters for the biggest surface pressure on robot. The results are showed that the variation of pressure and velocity is different on different position at 0.08s and 0.27s, and the surface pressure of the robot become greater by the increase of blood density or viscosity.

A Fluid–Structure Interaction Model of the Left Coronary Artery

2018 ◽  
Vol 140 (12) ◽  
Author(s):  
Daphne Meza ◽  
David A. Rubenstein ◽  
Wei Yin
Keyword(s):  
Blood Flow ◽  
Shear Stress ◽  
Coronary Artery ◽  
Blood Vessel ◽  
Spatial Information ◽  
Fluid Structure Interaction ◽  
Vascular Wall ◽  
Myocardial Contraction ◽  
Fluid Structure ◽  
Structure Interaction

A fluid–structure interaction (FSI) model of a left anterior descending (LAD) coronary artery was developed, incorporating transient blood flow, cyclic bending motion of the artery, and myocardial contraction. The three-dimensional (3D) geometry was constructed based on a patient's computed tomography angiography (CTA) data. To simulate disease conditions, a plaque was placed within the LAD to create a 70% stenosis. The bending motion of the blood vessel was prescribed based on the LAD spatial information. The pressure induced by myocardial contraction was applied to the outside of the blood vessel wall. The fluid domain was solved using the Navier–Stokes equations. The arterial wall was defined as a nonlinear elastic, anisotropic, and incompressible material, and the mechanical behavior was described using the modified hyper-elastic Mooney–Rivlin model. The fluid (blood) and solid (vascular wall) domains were fully coupled. The simulation results demonstrated that besides vessel bending/stretching motion, myocardial contraction had a significant effect on local hemodynamics and vascular wall stress/strain distribution. It not only transiently increased blood flow velocity and fluid wall shear stress, but also changed shear stress patterns. The presence of the plaque significantly reduced vascular wall tensile strain. Compared to the coronary artery models developed previously, the current model had improved physiological relevance.

Fluid-Structure Interaction Analysis of Pulsatile Blood Flow and Heat Transfer in Living Tissues During Thermal Therapy

2013 ◽  
Vol 135 (4) ◽  
Author(s):  
Abdalla Mohamed AlAmiri
Keyword(s):  
Blood Flow ◽  
Blood Vessel ◽  
Arterial Wall ◽  
Interaction Analysis ◽  
Fluid Structure Interaction ◽  
Thermal Therapy ◽  
Large Temperature ◽  
Fluid Structure ◽  
Weighted Residuals ◽  
Structure Interaction

The current numerical investigation tackles the fluid-structure interaction in a blood vessel subjected to a prescribed heating scheme on tumor tissues under thermal therapy. A pulsating incompressible laminar blood flow was employed to examine its impact on the flow and temperature distribution within the blood vessel. In addition, the arterial wall was modeled using the volume-averaged porous media theory. The motion of a continuous and deformable arterial wall can be described by a continuous displacement field resulting from blood pressure acting on the tissue. Moreover, discretization of the transport equations was achieved using a finite element scheme based on the Galerkin method of weighted residuals. The numerical results were validated by comparing them against documented studies in the literature. Three various heating schemes were considered: constant temperature, constant wall flux, and a step-wise heat flux. The first two uniform schemes were found to exhibit large temperature variation within the tumor, which might affect the surrounding healthy tissues. Meanwhile, larger vessels and flexible arterial wall models render higher variation of the temperature within the treated tumor, owing to the enhanced mixing in the vicinity of the bottom wall.

COMPARISON OF ANTIHYPERTENSIVE EFFECT OF MOXONIDINE VERSUS CLONIDINE IN RENAL FAILURE PATIENTS.

2018 ◽  
Vol 6 (9) ◽  
Author(s):  
DR.MATHEW GEORGE ◽  
DR.LINCY JOSEPH ◽  
MRS.DEEPTHI MATHEW ◽  
ALISHA MARIA SHAJI ◽  
BIJI JOSEPH ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Renal Failure ◽  
Blood Flow ◽  
Blood Vessel ◽  
Blood Vessels ◽  
High Blood Pressure ◽  
Antihypertensive Effect ◽  
The Body ◽  
Ability To Work ◽  
Blood Flows

Blood pressure is the force of blood pushing against blood vessel walls as the heart pumps out blood, and high blood pressure, also called hypertension, is an increase in the amount of force that blood places on blood vessels as it moves through the body. Factors that can increase this force include higher blood volume due to extra fluid in the blood and blood vessels that are narrow, stiff, or clogged(1). High blood pressure can damage blood vessels in the kidneys, reducing their ability to work properly. When the force of blood flow is high, blood vessels stretch so blood flows more easily. Eventually, this stretching scars and weakens blood vessels throughout the body, including those in the kidneys.

Blood Vessel Density Measured Using Dynamic Optical Coherence Tomography is a Tool for Wound Healers

2021 ◽  
pp. 153473462110173
Author(s):  
Rajgopal Mani ◽  
Jon Holmes ◽  
Kittipan Rerkasem ◽  
Nikolaos Papanas
Keyword(s):  
Blood Flow ◽  
Optical Coherence Tomography ◽  
Blood Vessel ◽  
Chronic Wounds ◽  
Vessel Density ◽  
Optical Coherence ◽  
Skin Microcirculation ◽  
Wound Edge ◽  
Venous Ulcers ◽  
Oct Imaging

Dynamic optical coherence tomography (D-OCT) is a relatively new technique that may be used to study the substructures in the retina, in the skin and its microcirculation. Furthermore, D-OCT is a validated method of imaging blood flow in skin microcirculation. The skin around venous and mixed arterio-venous ulcers was imaged and found to have tortuous vessels assumed to be angiogenic sprouts, and classified as dots, blobs, coils, clumps, lines, and curves. When these images were analyzed and measurements of vessel density were made, it was observed that the prevalence of coils and clumps in wound borders was significantly greater compared with those at wound centers. This reinforced the belief of inward growth of vessels from wound edge toward wound center which, in turn, reposed confidence in following the wound edge to study healing. D-OCT imaging permits the structure and the function of the microcirculation to be imaged, and vessel density measured. This offers a new vista of skin microcirculation and using it, to better understand angiogenesis in chronic wounds.

Modeling of aortic valve stenosis using fluid-structure interaction method

Perfusion ◽  
2021 ◽  
pp. 026765912199854
Author(s):  
Mohammad Javad Ghasemi Pour ◽  
Kamran Hassani ◽  
Morteza Khayat ◽  
Shahram Etemadi Haghighi
Keyword(s):  
Blood Flow ◽  
Aortic Valve ◽  
Fluid Structure Interaction ◽  
Three Dimensional ◽  
Fluid Structure ◽  
Structure Interaction ◽  
Relaxation Phase ◽  
Exercise Condition ◽  
Time Dependent Domain ◽  
Comparison Of The Results

Background and objectives: Fluid structure interaction (FSI) is defined as interaction of the structures with contacting fluids. The aortic valve experiences the interaction with blood flow in systolic phase. In this study, we have tried to predict the hemodynamics of blood flow through a normal and stenotic aortic valve in two relaxation and exercise conditions using a three-dimensional FSI method. Methods: The aorta valve was modeled as a three-dimensional geometry including a normal model and two others with 25% and 50% stenosis. The geometry of the aortic valve was extracted from CT images and the models were generated by MMIMCS software and then they were implemented in ANSYS software. The pulsatile flow rate was used for all cases and the numerical simulations were conducted based on a time-dependent domain. Results: The obtained results including the velocity, pressure, and shear stress contours in different systolic time sequences were explained and discussed. The maximum blood flow velocity in relaxation phase was obtained 1.62 m/s (normal valve), 3.78 m/s (25% stenosed valve), and 4.73 m/s (50% stenosed valve). In exercise condition, the maximum velocities are 2.86, 4.32, and 5.42 m/s respectively. The maximum blood pressure in relaxation phase was calculated 111.45 mmHg (normal), 148.66 mmHg (25% stenosed), and 164.21 mmHg (50% stenosed). However, the calculated values in exercise situation were 129.57, 163.58, and 191.26 mmHg. The validation of the predicted results was also conducted using existing literature. Conclusions: We believe that such model are useful tools for biomechanical experts. The further studies should be done using experimental data and the data are implemented on the boundary conditions for better comparison of the results.

Coronary vasodilation mediated by T cells expressing choline acetyltransferase

2021 ◽  
Vol 321 (5) ◽  
pp. H933-H939
Author(s):  
Adrian H. Chester ◽  
Ann McCormack ◽  
Edmund J. Miller ◽  
Mohamed N. Ahmed ◽  
Magdi H. Yacoub
Keyword(s):  
T Cells ◽  
Blood Flow ◽  
Blood Vessel ◽  
Coronary Blood Flow ◽  
Choline Acetyltransferase ◽  
Vascular Endothelium ◽  
Coronary Circulation ◽  
Direct Interaction ◽  
Coronary Vasodilation ◽  
Ischemic Events

This study shows ChAT-expressing T cells can induce vasodilation of the blood vessel in the coronary circulation and that this effect relies on a direct interaction between T cells and the coronary vascular endothelium. The study establishes a potential immunomodulatory role for T cells in the coronary circulation. The present findings offer an additional possibility that a deficiency of ChAT-expressing T cells could contribute to reduced coronary blood flow and ischemic events in the myocardium.

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