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Zhao N, Zhang T, Zhang T, Wang B, Mu W, Wang F. Effect of blood viscosity on the hemodynamics of arteriovenous fistulae based on numerical investigation. Comput Methods Biomech Biomed Engin 2024:1-13. [PMID: 38563312 DOI: 10.1080/10255842.2024.2333926] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2023] [Accepted: 03/18/2024] [Indexed: 04/04/2024]
Abstract
Arteriovenous fistula (AVF) is the most commonly used vascular access for hemodialysis in patients with end-stage renal disease. Vascular diseases such as atherosclerosis and thrombosis, triggered by altered hemodynamic conditions, are the main causes of access failure. Changes in blood viscosity accelerate access dysfunction by affecting local velocities and wall shear stress (WSS) distribution in the circulation. Numerical simulation was employed to analyze and compare the hemodynamic behavior of AVF under different blood viscosities (0.001-0.012 Pa∙s). An idealized three-dimensional model with end-to-side anastomosis was established. Transient simulations were conducted using pulsatile inlet velocity and outflow as boundary conditions. The simulation results reveal the blood flow state of AVF under different viscosity physiological conditions and derive the rule of change. When blood viscosity increases, the local velocity in the disturbed region slows down and the stagnation time becomes longer, resulting in increased deposition of substances. As blood viscosity increases, the level of shear stress on the entire wall of the fistula increases accordingly. WSS values at high viscosities above 0.007 Pa∙s showed significantly larger low-shear regions near the anastomosis and increased chances of inducing atheromatous plaques. This research has revealed the correlation between blood dynamic viscosity and the hemodynamic behavior of AVF. Elevated whole blood viscosity increases the incidence of access obstruction and vascular disease leading to fistula failure. The study provides a basis for optimizing the distribution of hemodynamic parameters in the fistula for hemodialysis patients.
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Affiliation(s)
- Ning Zhao
- School of Quality and Technical Supervision, Hebei University, Baoding, China
| | - Tian Zhang
- School of Quality and Technical Supervision, Hebei University, Baoding, China
| | - Tianyu Zhang
- School of Quality and Technical Supervision, Hebei University, Baoding, China
| | - Baohui Wang
- School of Quality and Technical Supervision, Hebei University, Baoding, China
| | - Weina Mu
- School of Quality and Technical Supervision, Hebei University, Baoding, China
- Baoding No.1 Central Hospital, Baoding, China
| | - Fan Wang
- School of Quality and Technical Supervision, Hebei University, Baoding, China
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Ling Y, Tang J, Liu H. Numerical investigation of two-phase non-Newtonian blood flow in bifurcate pulmonary arteries with a flow resistant using Eulerian multiphase model. Chem Eng Sci 2021. [DOI: 10.1016/j.ces.2020.116426] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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Bahrami S, Norouzi M. Hemodynamic impacts of hematocrit level by two-way coupled FSI in the left coronary bifurcation. Clin Hemorheol Microcirc 2020; 76:9-26. [DOI: 10.3233/ch-200854] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Cardiovascular disease is now under the influence of several factors that encourage researchers to investigate the flow of these vessels. Oscillation influences the blood circulation in the volume of red blood cells (RBC) strongly. Therefore, in this study, its effects have been considered on hemodynamic parameters in the elastic wall and coronary bifurcation. In this study, a 3D geometry of non-Newtonian and pulsatile blood circulation is considered in the left coronary artery bifurcation. The Casson model with various hematocrits is analyzed in elastic and rigid walls. The wall shear stress (WSS) cannot show the stenosis artery alone, therefore, the oscillatory shear index (OSI) is represented as a hemodynamic parameter of WSS individually of time. The results are determined using two-way fluid-structure interaction (FSI) coupling method using an arbitrary Lagrangian-Eulerian method. The most prominent difference in velocity happened in the bifurcation and at hematocrit 30 with yield stress 6.59E-04 Pa. The backflow and vortex flow in the LCx branch grown with increasing shear rates. The likelihood of plaque generation at the ending of the LM branch is observed in hematocrits 10 and 20, while the WSS magnitude is normal in the hematocrit 60 with the greatest yield stress in the bifurcation. The shear stress among the rigid and elastic models is the highest at the ending of the LM branch. The wall shear stress magnitude among the models decreased at most of 24.49% by dividing the flow. Time-independent results for models showed that there is the highest value of OSI at the bifurcation, which then quickly dropped.
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Affiliation(s)
- Saeed Bahrami
- Faculty of Mechanical Engineering, Shahrood University of Technology, Shahrood, Semnan, Iran
| | - Mahmood Norouzi
- Faculty of Mechanical Engineering, Shahrood University of Technology, Shahrood, Semnan, Iran
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Numerical investigations of temperature and hemodynamics in carotid arteries with and without atherosclerotic plaque during open surgery. J Therm Biol 2020; 91:102622. [PMID: 32716871 DOI: 10.1016/j.jtherbio.2020.102622] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2020] [Revised: 04/02/2020] [Accepted: 05/11/2020] [Indexed: 11/23/2022]
Abstract
Intraoperative monitoring is essential for providing safe and effective care during open surgery. In this paper, numerical simulation is performed to track the flow and heat transfer of carotid arteries with and without atherosclerotic plaque in a real physiological system during surgery, in which the heat transport is first considered to couple to the blood flow due to the temperature dependence of the blood viscosity. The impacts of the operating room temperature and hematocrit (H) on the viscosity, velocity, temperature, wall shear stress (WSS), pressure drop and oscillation are investigated. The results demonstrate that the presence of plaque in the carotid artery induces a greater blood flow velocity, pressure drop, WSS, and oscillation, as well as a smaller viscosity and temperature variations. A decreasing ambient temperature leads to a decrease in the temperature and an increase in the low-WSS area, which implies a greater risk of hypothermia and atherosclerosis. As H increases, the high-WSS areas substantially expand; when H varies from 65% to 80%, WSSave increases by 70.02% and 68.57% for the arteries with and without plaque, respectively, which indicates a higher risk of vascular injury. The results obtained can serve as a guideline regarding the selection of an operating room temperature for carotid disease patients with distinct hematocrits.
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Felicetti L, Femminella M, Reali G. A Molecular Communications System for Live Detection of Hyperviscosity Syndrome. IEEE Trans Nanobioscience 2020; 19:410-421. [PMID: 32248117 DOI: 10.1109/tnb.2020.2984880] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The hyperviscosity syndrome consists of an excessive viscosity of the blood. It has to be timely detected, since it significantly increases the risk of many cardiovascular diseases. It can manifest essentially in two different ways, depending on the capability of the cardiocirculatory system to compensate the increased resistance experienced by the blood in vessels. In case of compensation, the blood flow velocity remains nearly unaltered; otherwise a significant decrease can occur. In this paper, we propose a blood viscosity monitoring system based on molecular communications. It could be used in risky patients for continuous monitoring and can detect blood hyperviscosity both in case of compensation, even partial, and in case of uncompensated cardiocirculatory systems. This proposal results to be both simple and effective for real time estimating the blood viscosity level, without any need of resorting to invasive blood analyses. The main idea is to leverage the statistics of particle dispersion and absorption in a blood vessel as a function of blood viscosity. Viscosity is estimated by processing the statistics of the received signal molecules, which are easy to collect. These features open the way to the implementation of the proposed solution in a simple and cheap device.
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Besseris GJ. Synchronous screening-and-optimization of nano-engineered blood pressure-drop using rapid robust non-linear Taguchi profiling. Chem Eng Sci 2019. [DOI: 10.1016/j.ces.2019.03.035] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
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Abstract
The Abdominal Aortic Aneurysm (AAA) is a local dilation of the abdominal aorta and it is a cause for serious concern because of the high mortality associated with its rupture. Consequently, the understanding of the phenomena related to the creation and the progression of an AAA is of crucial importance. In this work, the complicated interaction between the blood flow and the AAA wall is numerically examined using a fully coupled Fluid-Structure Interaction (FSI) method. The study investigates the possible link between the dynamic behavior of an AAA and the blood viscosity variations attributed to the haematocrit value, while it also incorporates the pulsatile blood flow, the non-Newtonian behavior of blood and the hyperelasticity of the arterial wall. It was found that blood viscosity has no significant effect on von Mises stress magnitude and distribution, whereas there is a close relation between the haematocrit value and the Wall Shear Stress (WSS) magnitude in AAAs. This WSS variation can possibly alter the mechanical properties of the arterial wall and increase its growth rate or even its rupture possibility. The relationship between haematocrit and dynamic behavior of an AAA can be helpful in designing a patient specific treatment.
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A Simplified Model for Predicting Friction Factors of Laminar Blood Flow in Small-Caliber Vessels. FLUIDS 2018. [DOI: 10.3390/fluids3040075] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The aim of this study was to provide scientists with a straightforward correlation that can be applied to the prediction of the Fanning friction factor and consequently the pressure drop that arises during blood flow in small-caliber vessels. Due to the small diameter of the conduit, the Reynolds numbers are low and thus the flow is laminar. This study has been conducted using Computational Fluid Dynamics (CFD) simulations validated with relevant experimental data, acquired using an appropriate experimental setup. The experiments relate to the pressure drop measurement during the flow of a blood analogue that follows the Casson model, i.e., an aqueous Glycerol solution that contains a small amount of Xanthan gum and exhibits similar behavior to blood, in a smooth, stainless steel microtube (L = 50 mm and D = 400 μm). The interpretation of the resulting numerical data led to the proposal of a simplified model that incorporates the effect of the blood flow rate, the hematocrit value (35–55%) and the vessel diameter (300–1800 μm) and predicts, with better than ±10% accuracy, the Fanning friction factor and consequently the pressure drop during laminar blood flow in healthy small-caliber vessels.
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Wain RAJ, Smith DJ, Hammond DR, Whitty JPM. Influence of microvascular sutures on shear strain rate in realistic pulsatile flow. Microvasc Res 2018. [PMID: 29522755 DOI: 10.1016/j.mvr.2018.03.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
Arterial thrombus formation is directly related to the mechanical shear experienced by platelets within flow. High shear strain rates (SSRs) and large shear gradients cause platelet activation, aggregation and production of thrombus. This study, for the first time, investigates the influence of pulsatile flow on local haemodynamics within sutured microarterial anastomoses. We measured physiological arterial waveform velocities experimentally using Doppler ultrasound velocimetry, and a representative example was applied to a realistic sutured microarterial geometry. Computational geometries were created using measurements taken from sutured chicken femoral arteries. Arterial SSRs were predicted using computational fluid dynamics (CFD) software, to indicate the potential for platelet activation, deposition and thrombus formation. Predictions of steady and sinusoidal inputs were compared to analyse whether the addition of physiological pulse characteristics affects local intravascular flow characteristics. Simulations were designed to evaluate flow in pristine and hand-sutured microarterial anastomoses, each with a steady-state and sinusoidal pulse component. The presence of sutures increased SSRmax in the anastomotic region by factors of 2.1 and 2.3 in steady-state and pulsatile flows respectively, when compared to a pristine vessel. SSR values seen in these simulations are analogous to the presence of moderate arterial stenosis. Steady-state simulations, driven by a constant inflow velocity equal to the peak systolic velocity (PSV) of the measured pulsatile flow, underestimated SSRs by ∼ 9% in pristine, and ∼ 19% in sutured vessels compared with a realistic pulse. Sinusoidal flows, with equivalent frequency and amplitude to a measured arterial waveform, represent a slight improvement on steady-state simulations, but still SSRs are underestimated by 1-2%. We recommend using a measured arterial waveform, of the form presented here, for simulating pulsatile flows in vessels of this nature. Under realistic pulsatile flow, shear gradients across microvascular sutures are high, of the order ∼ 7.9 × 106 m-1 s-1, which may also be associated with activation of platelets and formation of aggregates.
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Affiliation(s)
- R A J Wain
- School of Mathematics, University of Birmingham, B15 2TT, UK; Institute of Translational Medicine, University of Birmingham, B15 2TT, UK; School of Medicine and Dentistry, University of Central Lancashire, Preston PR1 2HE, UK; Computational Mechanics Research Group, School of Engineering, University of Central Lancashire, Preston PR1 2HE, UK.
| | - D J Smith
- School of Mathematics, University of Birmingham, B15 2TT, UK; Institute for Metabolism and Systems Research, University of Birmingham, B15 2TT, UK
| | - D R Hammond
- School of Medicine and Dentistry, University of Central Lancashire, Preston PR1 2HE, UK
| | - J P M Whitty
- Computational Mechanics Research Group, School of Engineering, University of Central Lancashire, Preston PR1 2HE, UK
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Iron-oxide nano-particles effect on the blood hemodynamics in atherosclerotic coronary arteries. Chem Eng Sci 2018. [DOI: 10.1016/j.ces.2017.11.048] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Impact of Yttrium-90 Microsphere Density, Flow Dynamics, and Administration Technique on Spatial Distribution: Analysis Using an In Vitro Model. J Vasc Interv Radiol 2016; 28:260-268.e2. [PMID: 27641675 DOI: 10.1016/j.jvir.2016.07.001] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2016] [Revised: 07/01/2016] [Accepted: 07/01/2016] [Indexed: 11/22/2022] Open
Abstract
PURPOSE To investigate material density, flow, and viscosity effects on microsphere distribution within an in vitro model designed to simulate hepatic arteries. MATERIALS AND METHODS A vascular flow model was used to compare distribution of glass and resin surrogates in a clinically derived flow range (60-120 mL/min). Blood-mimicking fluid (BMF) composed of glycerol and water (20%-50% vol/vol) was used to simulate a range of blood viscosities. Microsphere distribution was quantified gravimetrically, and injectate solution was dyed to enable quantification by UV spectrophotometry. Microsphere injection rate (5-30 mL/min) and the influence of contrast agent dilution of injection solution (0%-60% vol/vol) were also investigated. RESULTS No significant differences in behavior were observed between the glass and resin surrogate materials under any tested flow conditions (P = .182; n = 144 injections). Microspheres tend to align more consistently with the saline injection solution (r2 = 0.5712; n = 144) compared with total BMF flow distribution (r2 = 0.0104; n = 144). The most predictable injectate distribution (ie, greatest alignment with BMF flow, < 5% variation) was demonstrated with > 10-mL/min injection rates of pure saline solution, although < 20% variation with glass microsphere distribution was observed with injection solution containing as much as 30% contrast medium when injected at > 20 mL/min. CONCLUSIONS Glass and resin yttrium-90 surrogates demonstrated similar distribution in a range of clinically relevant flow conditions, suggesting that microsphere density does not have a significant influence on microsphere distribution. Injection parameters that enhanced the mixing of the spheres with the BMF resulted in the most predictable distribution.
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A micro-scale simulation of red blood cell passage through symmetric and asymmetric bifurcated vessels. Sci Rep 2016; 6:20262. [PMID: 26830454 PMCID: PMC4735796 DOI: 10.1038/srep20262] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2015] [Accepted: 12/31/2015] [Indexed: 12/20/2022] Open
Abstract
Blood exhibits a heterogeneous nature of hematocrit, velocity, and effective viscosity in microcapillaries. Microvascular bifurcations have a significant influence on the distribution of the blood cells and blood flow behavior. This paper presents a simulation study performed on the two-dimensional motions and deformation of multiple red blood cells in microvessels with diverging and converging bifurcations. Fluid dynamics and membrane mechanics were incorporated. Effects of cell shape, hematocrit, and deformability of the cell membrane on rheological behavior of the red blood cells and the hemodynamics have been investigated. It was shown that the blood entering the daughter branch with a higher flow rate tended to receive disproportionally more cells. The results also demonstrate that red blood cells in microvessels experienced lateral migration in the parent channel and blunted velocity profiles in both straight section and daughter branches, and this effect was influenced by the shape and the initial position of the cells, the hematocrit, and the membrane deformability. In addition, a cell free region around the tip of the confluence was observed. The simulation results are qualitatively consistent with existing experimental findings. This study may provide fundamental knowledge for a better understanding of hemodynamic behavior of micro-scale blood flow.
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Damiri HS, Bardaweel HK. Numerical design and optimization of hydraulic resistance and wall shear stress inside pressure-driven microfluidic networks. LAB ON A CHIP 2015; 15:4187-4196. [PMID: 26351133 DOI: 10.1039/c5lc00578g] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Microfluidic networks represent the milestone of microfluidic devices. Recent advancements in microfluidic technologies mandate complex designs where both hydraulic resistance and pressure drop across the microfluidic network are minimized, while wall shear stress is precisely mapped throughout the network. In this work, a combination of theoretical and modeling techniques is used to construct a microfluidic network that operates under minimum hydraulic resistance and minimum pressure drop while constraining wall shear stress throughout the network. The results show that in order to minimize the hydraulic resistance and pressure drop throughout the network while maintaining constant wall shear stress throughout the network, geometric and shape conditions related to the compactness and aspect ratio of the parent and daughter branches must be followed. Also, results suggest that while a "local" minimum hydraulic resistance can be achieved for a geometry with an arbitrary aspect ratio, a "global" minimum hydraulic resistance occurs only when the aspect ratio of that geometry is set to unity. Thus, it is concluded that square and equilateral triangular cross-sectional area microfluidic networks have the least resistance compared to all rectangular and isosceles triangular cross-sectional microfluidic networks, respectively. Precise control over wall shear stress through the bifurcations of the microfluidic network is demonstrated in this work. Three multi-generation microfluidic network designs are considered. In these three designs, wall shear stress in the microfluidic network is successfully kept constant, increased in the daughter-branch direction, or decreased in the daughter-branch direction, respectively. For the multi-generation microfluidic network with constant wall shear stress, the design guidelines presented in this work result in identical profiles of wall shear stresses not only within a single generation but also through all the generations of the microfluidic network under investigation. The results obtained in this work are consistent with previously reported data and suitable for a wide range of lab-on-chip applications.
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Affiliation(s)
- Hazem Salim Damiri
- Department of Mechanical Engineering, Faculty of Engineering and Technology, The University of Jordan, Amman, Jordan
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Wang H, Liu J, Zheng X, Rong X, Zheng X, Peng H, Silber-Li Z, Li M, Liu L. Three-dimensional virtual surgery models for percutaneous coronary intervention (PCI) optimization strategies. Sci Rep 2015; 5:10945. [PMID: 26042609 PMCID: PMC4455241 DOI: 10.1038/srep10945] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2015] [Accepted: 05/11/2015] [Indexed: 12/03/2022] Open
Abstract
Percutaneous coronary intervention (PCI), especially coronary stent implantation, has been shown to be an effective treatment for coronary artery disease. However, in-stent restenosis is one of the longstanding unsolvable problems following PCI. Although stents implanted inside narrowed vessels recover normal flux of blood flows, they instantaneously change the wall shear stress (WSS) distribution on the vessel surface. Improper stent implantation positions bring high possibilities of restenosis as it enlarges the low WSS regions and subsequently stimulates more epithelial cell outgrowth on vessel walls. To optimize the stent position for lowering the risk of restenosis, we successfully established a digital three-dimensional (3-D) model based on a real clinical coronary artery and analysed the optimal stenting strategies by computational simulation. Via microfabrication and 3-D printing technology, the digital model was also converted into in vitro microfluidic models with 3-D micro channels. Simultaneously, physicians placed real stents inside them; i.e., they performed “virtual surgeries”. The hydrodynamic experimental results showed that the microfluidic models highly inosculated the simulations. Therefore, our study not only demonstrated that the half-cross stenting strategy could maximally reduce restenosis risks but also indicated that 3-D printing combined with clinical image reconstruction is a promising method for future angiocardiopathy research.
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Affiliation(s)
- Hujun Wang
- Department of Precision Machinery and Precision Instrumentation, University of Science and Technology of China, Hefei 230026, China.,Key Laboratory of Soft Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Jinghua Liu
- Department of Cardiology, Beijing Anzhen Hospital, Capital Medical University, Beijing Institute of Heart, Lung and Blood Vessel Disease, Beijing 100029, China
| | - Xu Zheng
- State key laboratory of Nonlinear Mechanics, Institute of Mechanics, Chinese Academy of Sciences, Beijing 100190, China
| | - Xiaohui Rong
- Key Laboratory of Soft Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Xuwei Zheng
- Department of Cardiology, Beijing Anzhen Hospital, Capital Medical University, Beijing Institute of Heart, Lung and Blood Vessel Disease, Beijing 100029, China
| | - Hongyu Peng
- Department of Cardiology, Beijing Anzhen Hospital, Capital Medical University, Beijing Institute of Heart, Lung and Blood Vessel Disease, Beijing 100029, China
| | - Zhanghua Silber-Li
- State key laboratory of Nonlinear Mechanics, Institute of Mechanics, Chinese Academy of Sciences, Beijing 100190, China
| | - Mujun Li
- Department of Precision Machinery and Precision Instrumentation, University of Science and Technology of China, Hefei 230026, China
| | - Liyu Liu
- Key Laboratory of Soft Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
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Vinpocetine and pyritinol: a new model for blood rheological modulation in cerebrovascular disorders—a randomized controlled clinical study. BIOMED RESEARCH INTERNATIONAL 2014; 2014:324307. [PMID: 25548768 PMCID: PMC4274818 DOI: 10.1155/2014/324307] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/25/2014] [Revised: 08/21/2014] [Accepted: 09/16/2014] [Indexed: 01/29/2023]
Abstract
Blood and plasma viscosity are the major factors affecting blood flow and normal circulation. Whole blood viscosity is mainly affected by plasma viscosity, red blood cell deformability/aggregation and hematocrit, and other physiological factors. Thirty patients (twenty males + ten females) with age range 50-65 years, normotensive with history of cerebrovascular disorders, were selected according to the American Heart Stroke Association. Blood viscosity and other rheological parameters were measured after two-day abstinence from any medications. Dual effects of vinpocetine and pyritinol exhibit significant effects on all hemorheological parameters (P < 0.05), especially on low shear whole blood viscosity (P < 0.01), but they produced insignificant effects on total serum protein and high shear whole blood viscosity (P > 0.05). Therefore, joint effects of vinpocetine and pyritinol improve blood and plasma viscosity in patients with cerebrovascular disorders.
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Stogiannis I, Passos A, Mouza A, Paras S, Pěnkavová V, Tihon J. Flow investigation in a microchannel with a flow disturbing rib. Chem Eng Sci 2014. [DOI: 10.1016/j.ces.2014.07.055] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Holsworth RE, Cho YI, Weidman JJ, Sloop GD, Cyr JAS. Cardiovascular benefits of phlebotomy: relationship to changes in hemorheological variables. Perfusion 2013; 29:102-16. [DOI: 10.1177/0267659113505637] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Renewed interest in the age-old concept of “bloodletting”, a therapeutic approach practiced until as recently as the 19th century, has been stimulated by the knowledge that blood loss, such as following regular donation, is associated with significant reductions in key hemorheological variables, including whole blood viscosity (WBV), plasma viscosity, hematocrit and fibrinogen. An elevated WBV appears to be both a strong predictor of cardiovascular disease and an important factor in the development of atherosclerosis. Elevated WBV through wall shear stress is the most direct physiological parameter that influences the rupture and erosion of vulnerable plaques. In addition to WBV reduction, phlebotomy may reduce an individual’s cardiovascular risk through reductions in excessive iron, oxidative stress and inflammation. Reflecting these findings, blood donation in males has shown significant drops in the incidence of cardiovascular events, as well as in procedures such as percutaneous transluminal coronary angioplasty and coronary artery bypass grafting. Collectively, the available data on the benefits of therapeutic phlebotomy point to the importance of monitoring WBV as part of a cardiovascular risk factor, along with other risk-modifying measures, whenever an increased cardiovascular risk is detected. The development of a scanning capillary tube viscometer allows the measurement of WBV in a clinical setting, which can prove to be valuable in providing an early warning sign of an increased risk of cardiovascular disease.
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Affiliation(s)
- RE Holsworth
- Southeast Colorado Hospital, Springfield, CO, USA
| | - YI Cho
- Drexel University, Philadelphia, PA, USA
| | - J J Weidman
- Thomas Jefferson University, Philadelphia, PA, USA
| | - GD Sloop
- Benefis Hospitals, Great Falls, MT, USA
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Pereira J, Serra e Moura J, Ervilha A, Pereira J. On the uncertainty quantification of blood flow viscosity models. Chem Eng Sci 2013. [DOI: 10.1016/j.ces.2013.05.033] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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