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Kim HJ, Lee CM, Rundfeldt HC, Lee S, Lee I, Jansen K. Convergence of Phase-Averaged, Transitional Flow in an Abdominal Aortic Aneurysmal Model. J Biomech Eng 2023; 145:111007. [PMID: 37525577 DOI: 10.1115/1.4063066] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2022] [Accepted: 07/26/2023] [Indexed: 08/02/2023]
Abstract
Abdominal aortic aneurysm can exhibit transitional flow characteristics in laminar flow regimes. To report transitional flow characteristics, we examined the convergence of phase-averaged solutions by executing blood flow simulations of a patient-specific abdominal aortic aneurysmal model for 257 cardiac cycles with periodic, pulsatile boundary conditions. The phase-averaged solutions were computed by averaging the solutions over various numbers of cardiac cycles and compared against the ones averaged over 124 cycles. The phase-averaged solutions reported small differences when they were averaged over a large number of cardiac cycles. The instantaneous solutions, however, failed to exhibit fluctuations reported in the phase-averaged solutions. To study transitional blood flows in the aneurysmal region, we need to report phase-averaged solutions as they exhibit nonperiodic, disturbed flow characteristics. Additionally, when reporting phase-averaged solutions, it is preferred to compute an average over a large number of cardiac cycles to be able to represent flow structures of the converged phase-averaged solutions.
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Affiliation(s)
- Hyun Jin Kim
- Department of Mechanical Engineering, Korea Advanced Institute of Science and Technology, Daejeon 34141, South Korea
| | - Chang Min Lee
- Department of Mechanical Engineering, Korea Advanced Institute of Science and Technology, Daejeon 34141, South Korea
| | - Hans Christian Rundfeldt
- Department of Mechanical Engineering, Kalsruhe Institute of Technology, Karlsruhe 76131, Germany
| | - Seungmin Lee
- Department of Mechanical Engineering, Korea Advanced Institute of Science and Technology, Daejeon 34141, South Korea
| | - Inpyo Lee
- Department of Mechanical Engineering, Korea Advanced Institute of Science and Technology, Daejeon 34141, South Korea
| | - Kenneth Jansen
- Aerospace Engineering Sciences, University of Colorado Boulder, Boulder, CO 80303
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Conijn M, Krings GJ. Understanding stenotic pulmonary arteries: Can computational fluid dynamics help us out? PROGRESS IN PEDIATRIC CARDIOLOGY 2022. [DOI: 10.1016/j.ppedcard.2021.101452] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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3
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Fallon ME, Mathews R, Hinds MT. In Vitro Flow Chamber Design for the Study of Endothelial Cell (Patho)Physiology. J Biomech Eng 2022; 144:020801. [PMID: 34254640 PMCID: PMC8628846 DOI: 10.1115/1.4051765] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2020] [Revised: 07/06/2021] [Indexed: 02/03/2023]
Abstract
In the native vasculature, flowing blood produces a frictional force on vessel walls that affects endothelial cell function and phenotype. In the arterial system, the vasculature's local geometry directly influences variations in flow profiles and shear stress magnitudes. Straight arterial sections with pulsatile shear stress have been shown to promote an athero-protective endothelial phenotype. Conversely, areas with more complex geometry, such as arterial bifurcations and branch points with disturbed flow patterns and lower, oscillatory shear stress, typically lead to endothelial dysfunction and the pathogenesis of cardiovascular diseases. Many studies have investigated the regulation of endothelial responses to various shear stress environments. Importantly, the accurate in vitro simulation of in vivo hemodynamics is critical to the deeper understanding of mechanotransduction through the proper design and use of flow chamber devices. In this review, we describe several flow chamber apparatuses and their fluid mechanics design parameters, including parallel-plate flow chambers, cone-and-plate devices, and microfluidic devices. In addition, chamber-specific design criteria and relevant equations are defined in detail for the accurate simulation of shear stress environments to study endothelial cell responses.
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Affiliation(s)
- Meghan E. Fallon
- Department of Biomedical Engineering, Oregon Health & Science University, 3303 S Bond Ave CH13B, Portland, OR 97239
| | - Rick Mathews
- Department of Biomedical Engineering, Oregon Health & Science University, 3303 S Bond Ave CH13B, Portland, OR 97239
| | - Monica T. Hinds
- Department of Biomedical Engineering, Oregon Health & Science University, 3303 S Bond Ave CH13B, Portland, OR 97239
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Wan Sulaiman W, Chai S, Sanip Z, Ghulam Rasool A, Shokri A, Halim A, Mat Saad A. Systemic microvascular endothelial function with arteriovenous fistula creation in chronic kidney disease. JOURNAL OF RESEARCH IN MEDICAL SCIENCES 2022; 27:46. [PMID: 35968209 PMCID: PMC9374149 DOI: 10.4103/jrms.jrms_908_19] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Revised: 07/07/2020] [Accepted: 02/25/2022] [Indexed: 12/01/2022]
Abstract
Background: This study aimed to determine changes in microvascular endothelial function with upper arm arteriovenous fistula (AVF) creation and maturation in patients with chronic kidney disease (CKD). Materials and Methods: This prospective cross-sectional study was performed at Hospital Universiti Sains Malaysia, a tertiary hospital in Malaysia. Forty CKD patients (stage 4–5) who were scheduled for elective AVF creation over the upper extremity for maintenance hemodialysis were recruited using convenience sampling method. Microvascular endothelial-dependent vasodilation was measured using laser Doppler flowmetry and the process of iontophoresis preoperatively and postoperatively at weeks 2 and 6. Fistula maturation was assessed at week 6. Results: Thirty-two patients had successful AVF maturation. Endothelial-dependent vasodilation (acetylcholine (Ach)% was higher (246.48 [standard deviation (SD) 209.38] vs. 104.95 [SD 43.29], P = 0.001) while systolic blood pressure was lower (142.25 [SD 21.50] vs. 162.25 [SD 13.26], P = 0.017) in this group as compared to unsuccessful AVF group. No significant changes were seen in overall microvascular endothelial-dependent vasodilation during the 6-week study period (day 0, 246.48 [SD 209.38]; week 2, 201.14 [SD 198.19]; and week 6, 203.53 [SD 145.89]). Conclusion: Upper arm AVF creation does not affect microvascular endothelial function up to 6 weeks post operation and may not contribute to the success of AVF maturation. However, the lower microvascular endothelial-dependent vasodilation and higher systolic blood pressure in unsuccessful AVF subjects need to be further studied.
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Blood–Brain Barrier Dynamic Device with Uniform Shear Stress Distribution for Microscopy and Permeability Measurements. APPLIED SCIENCES-BASEL 2021. [DOI: 10.3390/app11125584] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Neurology has always been one of the therapeutic areas with higher attrition rates. One of the main difficulties is the presence of the blood–brain barrier (BBB) that restricts access to the brain for major drugs. This low success rate has led to an increasing demand for in vitro tools. The shear stress, which positively affects endothelial cell differentiation by mimicking blood flow, is required for a more physiological in vitro BBB model. We created an innovative device specifically designed for cell culture under shear stress to investigate drug permeability. Our dynamic device encompasses two compartments communicating together via a semi-permeable membrane, on which human cerebral microvascular endothelial (hCMEC/D3) cells were seeded. The fluidic controlled environment ensures a laminar and homogenous flow to culture cells for at least seven days. Cell differentiation was characterized by immunodetection of inter-endothelial junctions directly in the device by confocal microscopy. Finally, we performed permeability assay with lucifer yellow in both static and dynamic conditions in parallel. Our dynamic device is suited to the evaluation of barrier function and the study of drug transport across the BBB, but it could also be used with other human cell types to reproduce intestinal or kidney barriers.
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Manokawinchoke J, Pavasant P, Limjeerajarus CN, Limjeerajarus N, Osathanon T, Egusa H. Mechanical loading and the control of stem cell behavior. Arch Oral Biol 2021; 125:105092. [PMID: 33652301 DOI: 10.1016/j.archoralbio.2021.105092] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2020] [Revised: 01/08/2021] [Accepted: 02/21/2021] [Indexed: 12/14/2022]
Abstract
OBJECTIVE Mechanical stimulation regulates many cell responses. The present study describes the effects of different in vitro mechanical stimulation approaches on stem cell behavior. DESIGN The narrative review approach was performed. The articles published in English language that addressed the effects of mechanical force on stem cells were searched on Pubmed and Scopus database. The effects of extrinsic mechanical force on stem cell response was reviewed and discussed. RESULTS Cells sense mechanical stimuli by the function of mechanoreceptors and further transduce force stimulation into intracellular signaling. Cell responses to mechanical stimuli depend on several factors including type, magnitude, and duration. Further, similar mechanical stimuli exhibit distinct cell responses based on numerous factors including cell type and differentiation stage. Various mechanical applications modulate stemness maintenance and cell differentiation toward specific lineages. CONCLUSIONS Mechanical force application modulates stemness maintenance and differentiation. Modification of force regimens could be utilized to precisely control appropriate stem cell behavior toward specific applications.
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Affiliation(s)
- Jeeranan Manokawinchoke
- Department of Anatomy, Faculty of Dentistry, Chulalongkorn University, Bangkok, 10330, Thailand; Dental Stem Cell Biology Research Unit, Faculty of Dentistry, Chulalongkorn University, Bangkok, 10330, Thailand; Division of Molecular and Regenerative Prosthodontics, Tohoku University Graduate School of Dentistry, Sendai, 980-8575, Japan.
| | - Prasit Pavasant
- Department of Anatomy, Faculty of Dentistry, Chulalongkorn University, Bangkok, 10330, Thailand.
| | - Chalida Nakalekha Limjeerajarus
- Dental Stem Cell Biology Research Unit, Faculty of Dentistry, Chulalongkorn University, Bangkok, 10330, Thailand; Department of Physiology, Faculty of Dentistry, Chulalongkorn University, Bangkok, 10330, Thailand.
| | - Nuttapol Limjeerajarus
- Research Center for Advanced Energy Technology, Faculty of Engineering, Thai-Nichi Institute of Technology, Bangkok, 10250, Thailand.
| | - Thanaphum Osathanon
- Department of Anatomy, Faculty of Dentistry, Chulalongkorn University, Bangkok, 10330, Thailand; Dental Stem Cell Biology Research Unit, Faculty of Dentistry, Chulalongkorn University, Bangkok, 10330, Thailand.
| | - Hiroshi Egusa
- Division of Molecular and Regenerative Prosthodontics, Tohoku University Graduate School of Dentistry, Sendai, 980-8575, Japan.
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Zhang L, Li Y, Ma X, Liu J, Wang X, Zhang L, Li C, Li Y, Yang W. Ginsenoside Rg1-Notoginsenoside R1-Protocatechuic Aldehyde Reduces Atherosclerosis and Attenuates Low-Shear Stress-Induced Vascular Endothelial Cell Dysfunction. Front Pharmacol 2021; 11:588259. [PMID: 33568993 PMCID: PMC7868340 DOI: 10.3389/fphar.2020.588259] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2020] [Accepted: 12/14/2020] [Indexed: 12/31/2022] Open
Abstract
Background: The Fufang Danshen formula is a clinically important anti-atherosclerotic preparation in traditional Chinese medicine. However, its anti-atherosclerotic effect is not well recognized, and the mechanisms of its combined active ingredients, namely Ginsenoside Rg1-Notoginsenoside R1-Protocatechuic aldehyde (RRP), remain unclear. The purpose of this study was to investigate the anti-atherosclerotic effects and potential mechanism of RRP in ApoE-/- mice and in low-shear stress-injured vascular endothelial cells. Methods: ApoE-/- mice were randomly divided into three groups: model group, rosuvastatin group, and RRP group, with C57BL/6J mice as the control group. Oil-red O, hematoxylin and eosin, Masson, and Movat staining were utilized for the observation of aortic plaque. Changes in the blood lipid indexes were observed with an automatic biochemistry analyzer. ET-1, eNOS, TXA2, and PGI2 levels were analyzed by enzyme-linked immunosorbent assay. In vitro, a fluid shear stress system was used to induce cell injury. Piezo1 expression in HUVECs was silenced using siRNA. Changes in morphology, proliferation, migration, and tube formation activity of cells were observed after RRP treatment. Quantitative Real-Time PCR and western blot analysis were employed to monitor mRNA and protein expression. Results: RRP treatment reduced the atherosclerotic area and lipid levels and improved endothelial function in ApoE-/- mice. RRP significantly repaired cell morphology, reduced excessive cell proliferation, and ameliorated migration and tube formation activity. In addition, RRP affected the FAK-PI3K/Akt signaling pathway. Importantly, Piezo1 silencing abolished the protective effects of RRP. Conclusion: RRP has anti-atherosclerotic effects and antagonizes endothelial cell damage via modulating the FAK-PI3K/Akt signaling pathway. Piezo1 is a possible target of RRP in the treatment of atherosclerosis. Thus, RRP has promising therapeutic potential and broad application prospect for atherosclerosis.
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Affiliation(s)
- Lei Zhang
- First Faculty of Clinical Medicine, Shandong University of Traditional Chinese Medicine, Jinan, China
| | - Yuan Li
- Experimental Center, Shandong University of Traditional Chinese Medicine, Jinan, China
- Key Laboratory of Traditional Chinese Medicine Classic Theory, Ministry of Education, Shandong University of Traditional Chinese Medicine, Jinan, China
- Shandong Provincial Key Laboratory of Traditional Chinese Medicine for Basic Research, Shandong University of Traditional Chinese Medicine, Jinan, China
| | - Xin Ma
- First Faculty of Clinical Medicine, Shandong University of Traditional Chinese Medicine, Jinan, China
| | - Jiali Liu
- Faculty of Traditional Chinese Medicine, Shandong University of Traditional Chinese Medicine, Jinan, China
| | - Xiaojie Wang
- Faculty of Traditional Chinese Medicine, Shandong University of Traditional Chinese Medicine, Jinan, China
| | - Lingxiao Zhang
- Faculty of Traditional Chinese Medicine, Shandong University of Traditional Chinese Medicine, Jinan, China
| | - Chao Li
- Experimental Center, Shandong University of Traditional Chinese Medicine, Jinan, China
| | - Yunlun Li
- Experimental Center, Shandong University of Traditional Chinese Medicine, Jinan, China
- Cardiovascular Department, Affiliated Hospital of Shandong University of Traditional Chinese Medicine, Jinan, China
| | - Wenqing Yang
- Experimental Center, Shandong University of Traditional Chinese Medicine, Jinan, China
- Key Laboratory of Traditional Chinese Medicine Classic Theory, Ministry of Education, Shandong University of Traditional Chinese Medicine, Jinan, China
- Shandong Provincial Key Laboratory of Traditional Chinese Medicine for Basic Research, Shandong University of Traditional Chinese Medicine, Jinan, China
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Bortot M, Ashworth K, Sharifi A, Walker F, Crawford NC, Neeves KB, Bark D, Di Paola J. Turbulent Flow Promotes Cleavage of VWF (von Willebrand Factor) by ADAMTS13 (A Disintegrin and Metalloproteinase With a Thrombospondin Type-1 Motif, Member 13). Arterioscler Thromb Vasc Biol 2019; 39:1831-1842. [DOI: 10.1161/atvbaha.119.312814] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Objective—
Acquired von Willebrand syndrome is defined by excessive cleavage of the VWF (von Willebrand Factor) and is associated with impaired primary hemostasis and severe bleeding. It often develops when blood is exposed to nonphysiological flow such as in aortic stenosis or mechanical circulatory support. We evaluated the role of laminar, transitional, and turbulent flow on VWF cleavage and the effects on VWF function.
Approach and Results—
We used a vane rheometer to generate laminar, transitional, and turbulent flow and evaluate the effect of each on VWF cleavage in the presence of ADAMTS13 (a disintegrin and metalloproteinase with a thrombospondin type-1 motif, member 13). We performed functional assays to evaluate the effect of these flows on VWF structure and function. Computational fluid dynamics was used to estimate the flow fields and forces within the vane rheometer under each flow condition. Turbulent flow is required for excessive cleavage of VWF in an ADAMTS13-dependent manner. The assay was repeated with whole blood, and the turbulent flow had the same effect. Our computational fluid dynamics results show that under turbulent conditions, the Kolmogorov scale approaches the size of VWF. Finally, cleavage of VWF in this study has functional consequences under flow as the resulting VWF has decreased ability to bind platelets and collagen.
Conclusions—
Turbulent flow mediates VWF cleavage in the presence of ADAMTS13, decreasing the ability of VWF to sustain platelet adhesion. These findings impact the design of mechanical circulatory support devices and are relevant to pathological environments where turbulence is added to circulation.
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Affiliation(s)
- Maria Bortot
- From the Department of Pediatrics (M.B., K.A., F.W., K.B.N., D.B., J.D.P.), University of Colorado Anschutz Medical Campus, Aurora
- Department of Bioengineering (M.B., K.B.N.), University of Colorado Anschutz Medical Campus, Aurora
| | - Katrina Ashworth
- From the Department of Pediatrics (M.B., K.A., F.W., K.B.N., D.B., J.D.P.), University of Colorado Anschutz Medical Campus, Aurora
| | - Alireza Sharifi
- Department of Mechanical Engineering (A.S., D.B.), Colorado State University, Fort Collins
| | - Faye Walker
- From the Department of Pediatrics (M.B., K.A., F.W., K.B.N., D.B., J.D.P.), University of Colorado Anschutz Medical Campus, Aurora
| | - Nathan C. Crawford
- Department of Material Characterization, Thermo Fisher Scientific, Madison, WI (N.C.C.)
| | - Keith B. Neeves
- From the Department of Pediatrics (M.B., K.A., F.W., K.B.N., D.B., J.D.P.), University of Colorado Anschutz Medical Campus, Aurora
- Department of Bioengineering (M.B., K.B.N.), University of Colorado Anschutz Medical Campus, Aurora
| | - David Bark
- From the Department of Pediatrics (M.B., K.A., F.W., K.B.N., D.B., J.D.P.), University of Colorado Anschutz Medical Campus, Aurora
- Department of Mechanical Engineering (A.S., D.B.), Colorado State University, Fort Collins
- School of Biomedical Engineering (D.B.), Colorado State University, Fort Collins
| | - Jorge Di Paola
- From the Department of Pediatrics (M.B., K.A., F.W., K.B.N., D.B., J.D.P.), University of Colorado Anschutz Medical Campus, Aurora
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Characterization and estimation of turbulence-related wall shear stress in patient-specific pulsatile blood flow. J Biomech 2019; 85:108-117. [PMID: 30704762 DOI: 10.1016/j.jbiomech.2019.01.016] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2018] [Revised: 11/26/2018] [Accepted: 01/08/2019] [Indexed: 11/22/2022]
Abstract
Disturbed, turbulent-like blood flow promotes chaotic wall shear stress (WSS) environments, impairing essential endothelial functions and increasing the susceptibility and progression of vascular diseases. These flow characteristics are today frequently detected at various anatomical, lesion and intervention-related sites, while their role as a pathological determinant is less understood. To present-day, numerous WSS-based descriptors have been proposed to characterize the spatiotemporal nature of the WSS disturbances, however, without differentiation between physiological laminar oscillations and turbulence-related WSS (tWSS) fluctuations. Also, much attention has been focused on magnetic resonance (MR) WSS estimations, so far with limited success; promoting the need of a near-wall surrogate marker. In this study, a new approach is explored to characterize the tWSS, by taking advantage of the tensor characteristics of the fluctuating WSS correlations, providing both a magnitude and an anisotropy measure of the disturbances. These parameters were studied in two patient-specific coarctation models (sever and mild), using large eddy simulations, and correlated against near-wall reciprocal Reynolds stress parameters. Collectively, results showed distinct regions of differing tWSS characteristics, features which were sensitive to changes in flow conditions. Generally, the post-stenotic tWSS was governed by near axisymmetric fluctuations, findings that where not consistent with conventional WSS disturbance predictors. At the 2-3 mm wall-offset range, a strong linear correlation was found between tWSS magnitude and near-wall turbulence kinetic energy (TKE), in contrast to the anisotropy indices, suggesting that MR-measured TKE can be used to assess elevated tWSS regions while tWSS anisotropy estimates request well-resolved simulation methods.
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Biswas D, Casey DM, Crowder DC, Steinman DA, Yun YH, Loth F. Characterization of Transition to Turbulence for Blood in a Straight Pipe Under Steady Flow Conditions. J Biomech Eng 2017; 138:2517983. [PMID: 27109010 DOI: 10.1115/1.4033474] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2014] [Indexed: 11/08/2022]
Abstract
Blood is a complex fluid that, among other things, has been established to behave as a shear thinning, non-Newtonian fluid when exposed to low shear rates (SR). Many hemodynamic investigations use a Newtonian fluid to represent blood when the flow field of study has relatively high SR (>200 s-1). Shear thinning fluids have been shown to exhibit differences in transition to turbulence (TT) compared to that of Newtonian fluids. Incorrect prediction of the transition point in a simulation could result in erroneous hemodynamic force predictions. The goal of the present study was to compare velocity profiles near TT of whole blood and Newtonian blood analogs in a straight rigid pipe with a diameter 6.35 mm under steady flow conditions. Rheology was measured for six samples of whole porcine blood and three samples of a Newtonian fluid, and the results show blood acts as a shear thinning non-Newtonian fluid. Measurements also revealed that blood viscosity at SR = 200 s-1 is significantly larger than at SR = 1000 s-1 (13.8%, p < 0.001). Doppler ultrasound (DUS) was used to measure velocity profiles for blood and Newtonian samples at different flow rates to produce Reynolds numbers (Re) ranging from 1000 to 3300 (based on viscosity at SR = 1000 s-1). Two mathematically defined methods, based on the velocity profile shape change and turbulent kinetic energy (TKE), were used to detect TT. Results show similar parabolic velocity profiles for both blood and the Newtonian fluid for Re < 2200. However, differences were observed between blood and Newtonian fluid velocity profiles for larger Re. The Newtonian fluid had blunt-like velocity profiles starting at Re = 2403 ± 8 which indicated transition. In contrast, blood did not show this velocity profile change until Re = 2871 ± 104. The Newtonian fluid had large velocity fluctuations (root mean square (RMS) > 20%) with a maximum TKE near the pipe center at Re = 2316 ± 34 which indicated transition. In contrast, blood results showed the maximum TKE at Re = 2806 ± 109. Overall, the critical Re was delayed by ∼20% (p < 0.001) for blood compared to the Newtonian fluid. Thus, a Newtonian assumption for blood at flow conditions near transition could lead to large errors in velocity prediction for steady flow in a straight pipe. However, these results are specific to this pipe diameter and not generalizable since SR is highly dependent on pipe diameter. Further research is necessary to understand this relation in different pipe sizes, more complex geometries, and under pulsatile flow conditions.
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Browne LD, Bashar K, Griffin P, Kavanagh EG, Walsh SR, Walsh MT. The Role of Shear Stress in Arteriovenous Fistula Maturation and Failure: A Systematic Review. PLoS One 2015; 10:e0145795. [PMID: 26716840 PMCID: PMC4696682 DOI: 10.1371/journal.pone.0145795] [Citation(s) in RCA: 59] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2015] [Accepted: 12/08/2015] [Indexed: 11/18/2022] Open
Abstract
INTRODUCTION Non-maturation and post-maturation venous stenosis are the primary causes of failure within arteriovenous fistulae (AVFs). Although the exact mechanisms triggering failure remain unclear, abnormal hemodynamic profiles are thought to mediate vascular remodelling and can adversely impact on fistula patency. AIM The review aims to clarify the role of shear stress on outward remodelling during maturation and evaluate the evidence supporting theories related to the localisation and development of intimal hyperplasia within AVFs. METHODS A systematic review of studies comparing remodelling data with hemodynamic data obtained from computational fluid dynamics of AVFs during and after maturation was conducted. RESULTS Outward remodelling occurred to reduce or normalise the level of shear stress over time in fistulae with a large radius of curvature (curved) whereas shear stress was found to augment over time in fistulae with a small radius of curvature (straight) coinciding with minimal to no increases in lumen area. Although this review highlighted that there is a growing body of evidence suggesting low and oscillating shear stress may stimulate the initiation and development of intimal medial thickening within AVFs. Further lines of evidence are needed to support the disturbed flow theory and outward remodelling findings before surgical configurations and treatment strategies are optimised to conform to them. This review highlighted that variation between the time of analysis, classification of IH, resolution of simulations, data processing techniques and omission of various shear stress metrics prevented forming pooling of data amongst studies. CONCLUSION Standardised measurements and data processing techniques are needed to comprehensively evaluate the relationship between shear stress and intimal medial thickening. Advances in image acquisition and flow quantifications coupled with the increasing prevalence of longitudinal studies commencing from fistula creation offer viable techniques and strategies to robustly evaluate the relationship between shear stress and remodelling during maturation and thereafter.
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Affiliation(s)
- Leonard D. Browne
- Centre for Applied Biomedical Engineering Research (CABER), Department of Mechanical, Aeronautical and Biomedical Engineering, Materials and Surface Science Institute, The Health Research Institute, University of Limerick, Limerick, Ireland
| | - Khalid Bashar
- Department of Vascular Surgery, Limerick University Hospital, Dooradoyle, Limerick, Ireland
| | - Philip Griffin
- Centre for Applied Biomedical Engineering Research (CABER), Department of Mechanical, Aeronautical and Biomedical Engineering, Materials and Surface Science Institute, The Health Research Institute, University of Limerick, Limerick, Ireland
| | - Eamon G. Kavanagh
- Department of Vascular Surgery, Limerick University Hospital, Dooradoyle, Limerick, Ireland
| | - Stewart R. Walsh
- Department of Vascular Surgery, Limerick University Hospital, Dooradoyle, Limerick, Ireland
- Department of Surgery, National University of Ireland, Galway, Ireland
| | - Michael T. Walsh
- Centre for Applied Biomedical Engineering Research (CABER), Department of Mechanical, Aeronautical and Biomedical Engineering, Materials and Surface Science Institute, The Health Research Institute, University of Limerick, Limerick, Ireland
- * E-mail:
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