Displaying publications 1 - 20 of 29 in total

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  1. Visualization of multiphase pulsatile blood over single phase blood flow in a patient specific stenosed left coronary artery using image processing technique
    Athani A, Ghazali NNN, Anjum Badruddin I, Kamangar S, Salman Ahmed NJ, Honnutagi A
    Biomed Mater Eng, 2023;34(1):13-35.
    PMID: 36278331 DOI: 10.3233/BME-211333
    BACKGROUND: Coronary arteries disease has been reported as one of the principal roots of deaths worldwide.

    OBJECTIVE: The aim of this study is to analyze the multiphase pulsatile blood flow in the left coronary artery tree with stenosis.

    METHODS: The 3D left coronary artery model was reconstructed using 2D computerized tomography (CT) scan images. The Red Blood Cell (RBC) and varying hemodynamic parameters for single and multiphase blood flow conditions were analyzed.

    RESULTS: Results asserted that the multiphase blood flow modeling has a maximum velocity of 1.017 m/s and1.339 m/s at the stenosed region during the systolic and diastolic phases respectively. The increase in Wall Shear Stress (WSS) observed at the stenosed region during the diastole phase as compared during the systolic phase. It was also observed that the highest Oscillatory Shear Index (OSI) regions are found in the downstream area of stenosis and across the bifurcations. The increase in RBCs velocity from 0.45 m/s to 0.6 m/s across the stenosis was also noticed.

    CONCLUSION: The computational multiphase blood flow analysis improves the understanding and accuracy of the complex flow conditions of blood elements (RBC and Plasma) and provides the progression of the disease development in the coronary arteries. This study helps to enhance the diagnosis of the blocked (stenosed) arteries more precisely compared to the single-phase blood flow modeling.

    Matched MeSH terms: Blood Flow Velocity/physiology
  2. Therapeutic effects of Schistosoma mansoni soluble egg antigen in high fat diet induced dyslipidemia, hepatic and cardiovascular pathology in mice
    Toulah FH, El-Aswad BEW, Harba NM, Naguib YM
    Trop Biomed, 2018 Dec 01;35(4):893-907.
    PMID: 33601839
    High-fat diet (HFD) can cause hyperlipidemia, fatty liver and cardiovascular disorders. Herein, we evaluated therapeutic effects and possible underlying mechanisms of actions of Schistosoma mansoni soluble egg antigen (SEA) against experimental HFD induced dyslipidemia, hepatic and cardiovascular pathology. Forty Swiss albino mice were divided into four groups (10 each); mice fed standard diet (SD), mice fed HFD, mice fed HFD for 8 weeks then infected by S. mansoni cercaria (HFD+I) and mice fed HFD for 8 weeks then treated with SEA (HFD+SEA), all mice were euthanized 16 weeks after starting the experiment. HFD+SEA mice showed significantly (p<0.001) reduced total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C) and triglycerides (TG), and significantly (p<0.05) increased high-density lipoprotein cholesterol (HDL-C) comparing to HFD mice with non-significant difference with HFD+I mice group. Doppler flowmetry showed significantly (p<0.01) lower arterial resistance and significantly (p<0.05) higher blood flow velocity in HFD+SEA and HFD+I mice groups than HFD mice. HFD+SEA mice revealed improving in liver and aortic pathology and these were better than HFD+I mice group. HFD+SEA and HFD+I mice groups had less myocardium lipid deposits, but still showing some congested blood vessels. HFD myocardium revealed strong CD34+ expression on immunohistochemistry study, while that of HFD+SEA showed weak and HFD+I mice had moderate expressions. HFD+SEA mice had significantly (p<0.01) lower serum IL-1β and vascular endothelial growth factor (VEGF) and significantly (p<0.001) higher serum transforming growth factor beta 1 (TGF-β1) and IL-10 than HFD mice with non-significant difference with HFD+I mice. In conclusion, SEA lowered serum lipids, improved aortic function, decreased liver and cardiovascular pathology in HFD mice, so, it is recommended to purify active molecules from SEA to develop anti-dyslipidemic treatment.
    Matched MeSH terms: Blood Flow Velocity
  3. The influence of curvature wall on the blood flow in stenosed artery: A computational study
    Ahamad NA, Kamangar S, Badruddin IA
    Biomed Mater Eng, 2018;29(3):319-332.
    PMID: 29578467 DOI: 10.3233/BME-181734
    The current study investigates the curvature effect due to various angles of curvature on the blood flow in human artery. The stenosis is considered to have three sizes 70%, 80% and 90% blockage before the curve section of artery. Numerical study of four different angle of curvature was considered to understand the flow behavior of artery having various curvatures, on the hemodynamics factors that includes drop in arterial pressure, flow velocity as well as wall shear stress. It was found that, the augmentation of the flow resistance due to the curvature increases in presence of stenosis. It was also noted that the wall shear is higher at the outer wall as compared to the inside wall in four models considered. Results showed that both the curvature of artery and size of the stenosis have significant impact. These two factors should be considered by cardiologist to assess the complexity of stenosis.
    Matched MeSH terms: Blood Flow Velocity*
  4. Fulltext Symptomatic presentation of carotid sinus hypersensitivity is associated with impaired cerebral autoregulation
    Tan MP, Chadwick TJ, Kerr SR, Parry SW
    J Am Heart Assoc, 2014 Jun;3(3):e000514.
    PMID: 24947997 DOI: 10.1161/JAHA.113.000514
    Carotid sinus hypersensitivity (CSH) is associated with syncope, unexplained falls, and drop attacks in older people but occurs asymptomatically in 35% of community-dwelling elders. We hypothesized that impaired cerebral autoregulation is associated with the conversion of asymptomatic CSH to symptomatic CSH. We therefore conducted a case-control study evaluating individuals with CSH with and without the symptoms of syncope or unexplained falls, as well as non-CSH controls, to determine whether the blood pressure and heart rate changes associated with CSH are associated with symptoms only when cerebral autoregulation is altered.
    Matched MeSH terms: Blood Flow Velocity
  5. Short-term effect of atorvastatin on endothelial function in healthy offspring of parents with type 2 diabetes mellitus
    Amudha K, Choy AM, Mustafa MR, Lang CC
    Cardiovasc Ther, 2008;26(4):253-61.
    PMID: 19035876 DOI: 10.1111/j.1755-5922.2008.00064.x
    Endothelial function is impaired in healthy subjects at risk of type 2 diabetes mellitus (DM). We investigated whether endothelial dysfunction can be normalized by statin therapy in this potentially predisposed population. Flow-mediated dilation (FMD) was measured in 56 first-degree relatives (FDRs) (normotensive, normal glucose tolerance) and 20 age-, sex-, and BMI-matched controls with no family history of DM. Other measurements included insulin resistance index using the homeostasis model of insulin resistance (HOMA(IR)), plasma lipids, and markers of inflammation. The FDRs were then randomized and treated with atorvastatin (80 mg) or placebo daily in a 4-week double-blind, placebo-controlled trial. The FDRs had significantly impaired FMD (4.4 +/- 8.1% vs. 13.0 +/- 4.2%; P < 0.001), higher HOMA(IR) (1.72 +/- 1.45 vs. 1.25 +/- 0.43; P = 0.002), and elevated levels of plasma markers of inflammation-highly sensitive C-reactive protein (hsCRP) (2.6 +/- 3.8 mg/L vs. 0.7 +/- 1.0 mg/L; P = 0.06), interleukin (IL)-6 (0.07 +/- 0.13 ng/mL vs. 0.03 +/- 0.01 ng/mL; P < 0.001), and soluble intercellular adhesion molecule (sICAM) (267.7 +/- 30.7 ng/mL vs. 238.2 +/- 20.4 ng/mL; P < 0.001). FMD improved in the atorvastatin-treated subjects when compared with the placebo-treated subjects (atorvastatin, from 3.7 +/- 8.5% to 9.8 +/- 7.3%; placebo, from 3.9 +/- 5.6% to 4.7 +/- 4.2%; P = 0.001). There were also reductions in the levels of IL-6 (0.08 +/- 0.02 ng/mL vs. 0.04 +/- 0.01 ng/mL; P < 0.001) and hsCRP (3.0 +/- 3.9 mg/L vs. 1.0 +/- 1.3 mg/L; P = 0.006). Our study suggests that treatment with atorvastatin may improve endothelial function and decrease levels of inflammatory markers in FDRs of type 2 DM patients.
    Matched MeSH terms: Blood Flow Velocity/drug effects
  6. Review on CFD simulation in heart with dilated cardiomyopathy and myocardial infarction
    Chan BT, Lim E, Chee KH, Abu Osman NA
    Comput Biol Med, 2013 May;43(4):377-85.
    PMID: 23428371 DOI: 10.1016/j.compbiomed.2013.01.013
    The heart is a sophisticated functional organ that plays a crucial role in the blood circulatory system. Hemodynamics within the heart chamber can be indicative of exert cardiac health. Due to the limitations of current cardiac imaging modalities, computational fluid dynamics (CFD) have been widely used for the purposes of cardiac function assessment and heart disease diagnosis, as they provide detailed insights into the cardiac flow field. An understanding of ventricular hemodynamics and pathological severities can be gained through studies that employ the CFD method. In this research the hemodynamics of two common myocardial diseases, dilated cardiomyopathy (DCM) and myocardial infarction (MI) were investigated, during both the filling phase and the whole cardiac cycle, through a prescribed geometry and fluid structure interaction (FSI) approach. The results of the research indicated that early stage disease identification and the improvement of cardiac assisting devices and therapeutic procedures can be facilitated through the use of the CFD method.
    Matched MeSH terms: Blood Flow Velocity
  7. Review of numerical methods for simulation of mechanical heart valves and the potential for blood clotting
    Zakaria MS, Ismail F, Tamagawa M, Aziz AFA, Wiriadidjaja S, Basri AA, et al.
    Med Biol Eng Comput, 2017 Sep;55(9):1519-1548.
    PMID: 28744828 DOI: 10.1007/s11517-017-1688-9
    Even though the mechanical heart valve (MHV) has been used routinely in clinical practice for over 60 years, the occurrence of serious complications such as blood clotting remains to be elucidated. This paper reviews the progress that has been made over the years in terms of numerical simulation method and the contribution of abnormal flow toward blood clotting from MHVs in the aortic position. It is believed that this review would likely be of interest to some readers in various disciplines, such as engineers, scientists, mathematicians and surgeons, to understand the phenomenon of blood clotting in MHVs through computational fluid dynamics.
    Matched MeSH terms: Blood Flow Velocity/physiology
  8. Pulse waveform analysis on temporal changes in ocular blood flow due to caffeine intake: a comparative study between habitual and non-habitual groups
    Ismail A, Bhatti MS, Faye I, Lu CK, Laude A, Tang TB
    Graefes Arch Clin Exp Ophthalmol, 2018 Sep;256(9):1711-1721.
    PMID: 29876732 DOI: 10.1007/s00417-018-4030-9
    PURPOSE: To evaluate and compare the temporal changes in pulse waveform parameters of ocular blood flow (OBF) between non-habitual and habitual groups due to caffeine intake.

    METHOD: This study was conducted on 19 healthy subjects (non-habitual 8; habitual 11), non-smoking and between 21 and 30 years of age. Using laser speckle flowgraphy (LSFG), three areas of optical nerve head were analyzed which are vessel, tissue, and overall, each with ten pulse waveform parameters, namely mean blur rate (MBR), fluctuation, skew, blowout score (BOS), blowout time (BOT), rising rate, falling rate, flow acceleration index (FAI), acceleration time index (ATI), and resistive index (RI). Two-way mixed ANOVA was used to determine the difference between every two groups where p 

    Matched MeSH terms: Blood Flow Velocity/physiology
  9. Patient specific 3-d modeling of blood flow in a multi-stenosed left coronary artery
    Kamangar S, Badruddin IA, Ameer Ahamad N, Soudagar MEM, Govindaraju K, Nik-Ghazali N, et al.
    Biomed Mater Eng, 2017;28(3):257-266.
    PMID: 28527189 DOI: 10.3233/BME-171672
    The current study investigates the effect of multi stenosis on the hemodynamic parameters such as wall pressure, velocity and wall shear stress in the realistic left coronary artery. Patients CT scan image data of normal and diseased left coronary artery was chosen for the reconstruction of 3D coronary artery models. The diseased 3D model of left coronary artery shows a narrowing of more than 70% and 80% of area stenosis (AS) at the left main stem (LMS) and left circumflex (LCX) respectively. The results show that the decrease in pressure was found downstream to the stenosis as compared to the coronary artery without stenosis. The maximum pressure drop was noted across the 80% AS at the left circumflex branch. The recirculation zone was also observed immediate to the stenosis and highest wall shear stress was found across the 80% area stenosis. Our analysis provides an insight into the distribution of wall shear stress and pressure drop, thus improving our understanding on the hemodynamics in realistic coronary artery.
    Matched MeSH terms: Blood Flow Velocity
  10. Fulltext Numerical solution of magnetohydrodynamics effects on a generalised power law fluid model of blood flow through a bifurcated artery with an overlapping shaped stenosis
    Zain NM, Ismail Z
    PLoS One, 2023;18(2):e0276576.
    PMID: 36780455 DOI: 10.1371/journal.pone.0276576
    This paper presents a numerical analysis of blood flow in a diseased vessel within the presence of an external magnetic field. The blood flow was considered to be incompressible and fully developed, in that the non-Newtonian nature of the fluid was characterised as a generalised power law model for shear-thinning, Newtonian, and shear-thickening fluids. The impact of a transverse directed external magnetic field on blood flow through a stenosed bifurcated artery was investigated. The arterial geometry was considered as a bifurcated channel with overlapping shaped stenosis. The problem was treated mathematically using the Galerkin Least-Squares (GLS) method. The implementation of this numerical method managed to overcome the numerical instability faced by the classical Galerkin technique when adopted to a highly viscous flow. The benefit of GLS in circumventing the Ladyzhenskaya-Babuška-Brezzi (LBB) condition was utilized by evaluating both the velocity and pressure components at corner nodes of a unstructured triangular element. The non-linearity that emerged from the convective terms was then treated using the Newton-Raphson method, while the numerical integrals were computed using a Gaussian quadrature rule with six quadrature points. The findings obtained from this study were then compared with available results from the literature as well as Comsol multiphysics software to verify the accuracy and validity of the numerical algorithms. It was found that the application of magnetic field was able to overcome flow reversal by 39% for a shear-thinning fluid, 26% for a Newtonian fluid, and 27% for a shear-thickening fluid. The negative pressure and steep wall shear stress which occurs at the extremities of an overlapping stenosis throat were diminished by rise in magnetic intensity. This prevented thrombosis occurrence and produced a uniform calm flow.
    Matched MeSH terms: Blood Flow Velocity/physiology
  11. Numerical simulations of flow through the aorta using both ideal and realistic geometrical models
    Wan Ab Naim WN, Ganesan P, Al Abed A, Lim E
    Annu Int Conf IEEE Eng Med Biol Soc, 2012;2012:653-6.
    PMID: 23365977 DOI: 10.1109/EMBC.2012.6346016
    The effects of curvature and tapering on the flow progression in the aorta were studied using numerical simulations on a realistic geometrical model of the aorta and three different versions of the ideal aorta models. The results showed that tapering increases velocity magnitude and wall shear stress while local curvatures affect the skewness of the velocity profile, the thickness of the boundary layer as well as the recirculation regions. Wall shear stress distribution in the aorta serves as an important determinant in the progression of arterial disease.
    Matched MeSH terms: Blood Flow Velocity
  12. Numerical simulation of effect of hybrid nanofluid on heat transfer and flow of the Newtonian pulsatile blood through 3D occluded artery: Silver and gold nanoparticles
    Koosha N, Mosavi V, Kheirollah J, Najafi N, Abdi N, Alizadeh A, et al.
    J Therm Biol, 2023 Oct;117:103718.
    PMID: 37812951 DOI: 10.1016/j.jtherbio.2023.103718
    The study of blood flow in obstructed arteries is a significant focus in computational fluid dynamics, particularly in the field of biomedicine. The primary objective of this research is to investigate the impact of pulsating blood velocity on heat transfer within biological systems, with a specific focus on blood flow in obstructed arteries. To achieve this goal, a comprehensive 3D model representing a straight, constricted blood vessel has been developed. This model incorporates periodic, unsteady, Newtonian blood flow along with the presence of gold and silver nanoparticles. Leveraging the Finite Element Method (FEM), the Navier-Stokes and energy equations have been rigorously solved. Through the investigation, it is aim to shed light on how alterations in the pulsation rate and the volume fraction of nanoparticles influence both temperature distribution and velocity profiles within the system. The present study findings unequivocally highlight that the behavior of pulsatile nanofluid flow significantly impacts the velocity field and heat transfer performance. However, it is imperative to note that the extent of this influence varies depending on the specific volume fractions involved. Specifically, higher volume fractions of nanofluids correlate with elevated velocities at the center of the vessel and decreased velocities near the vessel walls. This pattern also extends to the temperature distribution and heat flux within the vessel, further underscoring the paramount importance of pulsatile flow dynamics in biomedicine and computational fluid dynamics research. Besides, results revealed that the presence of occlusion significantly affects the heat transfer and fluid flow.
    Matched MeSH terms: Blood Flow Velocity/physiology
  13. Fulltext Numerical investigation of the effect of stenosis geometry on the coronary diagnostic parameters
    Kamangar S, Kalimuthu G, Badruddin IA, Badarudin A, Ahmed NJ, Khan TM
    ScientificWorldJournal, 2014;2014:354946.
    PMID: 25258722 DOI: 10.1155/2014/354946
    The present study deals with the functional severity of a coronary artery stenosis assessed by the fractional flow reserve (FFR). The effects of different geometrical shapes of lesion on the diagnostic parameters are unknown. In this study, 3D computational simulation of blood flow in three different geometrical shapes of stenosis (triangular, elliptical, and trapezium) is considered in steady and transient conditions for 70% (moderate), 80% (intermediate), and 90% (severe) area stenosis (AS). For a given percentage AS, the variation of diagnostic parameters which are derived from pressure drop across the stenosis was found in three different geometrical shapes of stenosis and it was observed that FFR is higher in triangular shape and lower in trapezium shape. The pressure drop coefficient (CDP) was higher in trapezium shape and lower in triangular model whereas the LFC shows opposite trend. From the clinical perspective, the relationship between percentage AS and FFR is linear and inversely related in all the three models. A cut-off value of 0.75 for FFR was observed at 76.5% AS in trapezium model, 79.5% in elliptical model, and 82.7% AS for the triangular shaped model. The misinterpretation of the functional severity of the stenosis is in the region of 76.5%-82.7 % AS from different shapes of stenosis models.
    Matched MeSH terms: Blood Flow Velocity
  14. Fulltext Numerical Solution of Blood Flow and Mass Transport in an Elastic Tube with Multiple Stenoses
    Alsemiry RD, Sarifuddin, Mandal PK, Sayed HM, Amin N
    Biomed Res Int, 2020;2020:7609562.
    PMID: 32090110 DOI: 10.1155/2020/7609562
    The simultaneous effect of flexible wall and multiple stenoses on the flow and mass transfer of blood is investigated through numerical computation and simulations. The solution is obtained using the Marker and Cell technique on an axisymmetric model of Newtonian blood flow. The results compare favorably with physical observations where the pulsatile boundary condition and double stenoses result in a higher pressure drop across the stenoses. The streamlines, the iso-concentration lines, the Sherwood number, and the mass concentration variations along the entire wall segment provide a comprehensive analysis of the mass transport characteristics. The double stenoses and pulsatile inlet conditions increase the number of recirculation regions and effect a higher mass transfer rate at the throat, whereby more mass is expected to accumulate and cause further stenosis.
    Matched MeSH terms: Blood Flow Velocity/physiology
  15. Modification of Aortic Cannula With an Inlet Chamber to Induce Spiral Flow and Improve Outlet Flow
    Darlis N, Osman K, Padzillah MH, Dillon J, Md Khudzari AZ
    Artif Organs, 2018 May;42(5):493-499.
    PMID: 29280161 DOI: 10.1111/aor.13021
    Physiologically, blood ejected from the left ventricle in systole exhibited spiral flow characteristics. This spiral flow has been proven to have several advantages such as lateral reduction of directed forces and thrombus formation, while it also appears to be clinically beneficial in suppressing neurological complications. In order to deliver spiral flow characteristics during cardiopulmonary bypass operation, several modifications have been made on an aortic cannula either at the internal or at the outflow tip; these modifications have proven to yield better hemodynamic performances compared to standard cannula. However, there is no modification done at the inlet part of the aortic cannula for inducing spiral flow so far. This study was carried out by attaching a spiral inducer at the inlet of an aortic cannula. Then, the hemodynamic performances of the new cannula were compared with the standard straight tip end-hole cannula. This is achieved by modeling the cannula and attaching the cannula at a patient-specific aorta model. Numerical approach was utilized to evaluate the hemodynamic performance, and a water jet impact experiment was used to demonstrate the jet force generated by the cannula. The new spiral flow aortic cannula has shown some improvements by reducing approximately 21% of impinging velocity near to the aortic wall, and more than 58% reduction on total force generated as compared to standard cannula.
    Matched MeSH terms: Blood Flow Velocity
  16. Left ventricular flow propagation velocity measurement: Is it cast in stone?
    Chan BT, Yeoh HK, Liew YM, Aziz YFA, Sridhar GS, Hamilton-Craig C, et al.
    Med Biol Eng Comput, 2017 Oct;55(10):1883-1893.
    PMID: 28321684 DOI: 10.1007/s11517-017-1639-5
    This study aims to investigate the measurement of left ventricular flow propagation velocity, V p, using phase contrast magnetic resonance imaging and to assess the discrepancies resulting from inflow jet direction and individual left ventricular size. Three V p measuring techniques, namely non-adaptive (NA), adaptive positions (AP) and adaptive vectors (AV) method, were suggested and compared. We performed the comparison on nine healthy volunteers and nine post-infarct patients at four measurement positions, respectively, at one-third, one-half, two-thirds and the conventional 4 cm distances from the mitral valve leaflet into the left ventricle. We found that the V p measurement was affected by both the inflow jet direction and measurement positions. Both NA and AP methods overestimated V p, especially in dilated left ventricles, while the AV method showed the strongest correlation with the isovolumic relaxation myocardial strain rate (r = 0.53, p 
    Matched MeSH terms: Blood Flow Velocity/physiology*
  17. Fulltext Lattice Boltzmann Model of 3D Multiphase Flow in Artery Bifurcation Aneurysm Problem
    Abas A, Mokhtar NH, Ishak MH, Abdullah MZ, Ho Tian A
    Comput Math Methods Med, 2016;2016:6143126.
    PMID: 27239221 DOI: 10.1155/2016/6143126
    This paper simulates and predicts the laminar flow inside the 3D aneurysm geometry, since the hemodynamic situation in the blood vessels is difficult to determine and visualize using standard imaging techniques, for example, magnetic resonance imaging (MRI). Three different types of Lattice Boltzmann (LB) models are computed, namely, single relaxation time (SRT), multiple relaxation time (MRT), and regularized BGK models. The results obtained using these different versions of the LB-based code will then be validated with ANSYS FLUENT, a commercially available finite volume- (FV-) based CFD solver. The simulated flow profiles that include velocity, pressure, and wall shear stress (WSS) are then compared between the two solvers. The predicted outcomes show that all the LB models are comparable and in good agreement with the FVM solver for complex blood flow simulation. The findings also show minor differences in their WSS profiles. The performance of the parallel implementation for each solver is also included and discussed in this paper. In terms of parallelization, it was shown that LBM-based code performed better in terms of the computation time required.
    Matched MeSH terms: Blood Flow Velocity
  18. Investigation of two-way fluid-structure interaction of blood flow in a patient-specific left coronary artery
    Athani A, Ghazali NNN, Badruddin IA, Kamangar S, Anqi AE, Algahtani A
    Biomed Mater Eng, 2022;33(1):13-30.
    PMID: 34366314 DOI: 10.3233/BME-201171
    BACKGROUND: The blood flow in the human artery has been a subject of sincere interest due to its prime importance linked with human health. The hemodynamic study has revealed an essential aspect of blood flow that eventually proved to be paramount to make a correct decision to treat patients suffering from cardiac disease.

    OBJECTIVE: The current study aims to elucidate the two-way fluid-structure interaction (FSI) analysis of the blood flow and the effect of stenosis on hemodynamic parameters.

    METHODS: A patient-specific 3D model of the left coronary artery was constructed based on computed tomography (CT) images. The blood is assumed to be incompressible, homogenous, and behaves as Non-Newtonian, while the artery is considered as a nonlinear elastic, anisotropic, and incompressible material. Pulsatile flow conditions were applied at the boundary. Two-way coupled FSI modeling approach was used between fluid and solid domain. The hemodynamic parameters such as the pressure, velocity streamline, and wall shear stress were analyzed in the fluid domain and the solid domain deformation.

    RESULTS: The simulated results reveal that pressure drop exists in the vicinity of stenosis and a recirculation region after the stenosis. It was noted that stenosis leads to high wall stress. The results also demonstrate an overestimation of wall shear stress and velocity in the rigid wall CFD model compared to the FSI model.

    Matched MeSH terms: Blood Flow Velocity
  19. Fulltext Influence of visceral fat and blood pressure on changes in blood flow velocity in non-obese individuals
    Rasyada AR, Sha'ban M, Azhim A
    Cardiovasc J Afr, 2018;29(3):146-149.
    PMID: 30067273 DOI: 10.5830/CVJA-2018-001
    INTRODUCTION: The aim of this study was to evaluate the impact of different visceral fat (VF) and blood pressure (BP) levels on changes in blood flow velocity (BFV) among non-obese subjects, using a cross-sectional study approach.

    METHODS: A total of 110 putatively healthy and non-obese subjects were divided into three groups according to their level of VF and BP. Common carotid artery BFV was measured using a developed portable Doppler ultrasound measurement system.

    RESULTS: The most pronounced peak systolic velocity (S1) was lower (p < 0.05) in the hypertensive group and the peak diastolic velocity (D) was significantly lower in the pre-hypertensive group than in the normotensive group. There were differences in velocity reflection and resistive indices between the hypertensive and other two BP groups. The higher VF group had significantly lower S1 and D velocities and resistive and vascular elasticity indices. By contrast, the velocity reflection index was larger in the higher VF group.

    CONCLUSIONS: We confirmed that there were significant differences in the BFV among non-obese subjects who differed in level of VF and BP. This study confirms that a putatively increasing VF and BP level is associated with the development of hypertension.

    Matched MeSH terms: Blood Flow Velocity
  20. Influence of stenosis on hemodynamic parameters in the realistic left coronary artery under hyperemic conditions
    Kamangar S, Badruddin IA, Badarudin A, Nik-Ghazali N, Govindaraju K, Salman Ahmed NJ, et al.
    Comput Methods Biomech Biomed Engin, 2017 Mar;20(4):365-372.
    PMID: 27612619 DOI: 10.1080/10255842.2016.1233402
    The current study investigates the hyperemic flow effects on heamodynamics parameters such as velocity, wall shear stress in 3D coronary artery models with and without stenosis. The hyperemic flow is used to evaluate the functional significance of stenosis in the current era. Patients CT scan data of having healthy and coronary artery disease was chosen for the reconstruction of 3D coronary artery models. The diseased 3D models of coronary artery shows a narrowing of >50% lumen area. Computational fluid dynamics was performed to simulate the hyperemic flow condition. The results showed that the recirculation zone was observed immediate to the stenosis and highest wall shear stress was observed across the stenosis. The decrease in pressure was found downstream to the stenosis as compared to the coronary artery without stenosis. Our analysis provides an insight into the distribution of wall shear stress and pressure drop, thus improving our understanding of hyperemic flow effect under both conditions.
    Matched MeSH terms: Blood Flow Velocity
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