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Effect of coronary artery dynamics on the wall shear stress vector field topological skeleton in fluid–structure interaction analyses

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International Journal of Mechanical System Dynamics 2023年第1期3卷 48-57页

作者： Harry J.Carpenter Mergen H.Ghayesh Anthony C.Zander Peter J.Psaltis School of Electrical and Mechanical Engineering University of AdelaideAdelaideSouth AustraliaAustralia Vascular Research Centre Lifelong Health ThemeSouth Australian Health and Medical Research Institute(SAHMRI)AdelaideSouth AustraliaAustralia Adelaide Medical School University of AdelaideAdelaideSouth AustraliaAustralia Department of Cardiology Central Adelaide Local Health NetworkAdelaideSouth AustraliaAustralia

In this paper,we investigate the impact of coronary artery dynamics on the wall shear stress(WSS)vector field topology by comparing fluid–structure interaction(FSI)and computational fluid dynamics(CFD)techniques.As one of the most common causes of death globally,coronary artery disease(CAD)is a significant economic burden;however,novel approaches are still needed to improve our ability to predict its progression.FSI can include the unique dynamical factors present in the coronary vasculature.To investigate the impact of these dynamical factors,we study an idealized artery model with sequential stenosis.The transient simulations made use of the hyperelastic artery and lipid constitutive equations,non‐Newtonian blood viscosity,and the characteristic out‐of‐phase pressure and velocity distribution of the left anterior descending coronary artery.We compare changes to established metrics of time‐averaged WSS(TAWSS)and the oscillatory shear index(OSI)to changes in the emerging WSS divergence,calculated here in a modified version to handle the deforming mesh of FSI simulations.Results suggest that the motion of the artery can impact downstream patterns in both divergence and OSI.WSS magnitude is also decreased by up to 57%due to motion in some regions.WSS divergence patterns varied most significantly between simulations over the systolic period,the time of the largest displacements.This investigation highlights that coronary dynamics could impact markers of potential CAD progression and warrants further detailed investigations in more diverse geometries and patient cases.

关键词： computational fluid dynamics divergence fluid–structure interaction topology wall shear stress

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Non-invasive assessment of intracranial wall shear stress using high-resolution magnetic resonance imaging in combination with computational fluid dynamics technique

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Fundamental Research 2022年第2期2卷 329-334页

作者： Yuwen Chen Jia Liu Mingli Li Yannan Yu Zhengzheng Yan Wenshin Shiu Bokai Wu Zaiheng Cheng Yao Meng Yang Liu Weizhuang Yuan Zongmuyu Zhang Weihai Xu Department of Neurology State Key Laboratory of Complex Severe and Rare DiseasesPeking Union Medical Cllege HospitalChinese Academy of Medical Sciences and Peking Union Medical College1 ShuaifuyuanBeijing 100005China Department of Cardiology Second Afliated Hospital of Zhejiang University School of MedicineHangzhouZhejiang 310009China Shenzhen Instiutes of Advanced Technology Chinese Academy of SciencesShenzhen 518055China Shenzhen Key Laboratory for Exascale Engineering and Scientific Computing Shenzhen 518055China Department of Radiology Peking Union Medical College HospitalChinese Acadermy of Medical Sciences1 ShuaifiryuanBeijing 100005China Department of Radiology Stanford UniversityCaliformia 94305United States Department of Neurology Saarland UniversityKirrberger StraSe 66421Germany

In vivo studies on association between wall shear stress(WSS)and intracranial plaque are deficient.Based on the three-dimensional T1-weighted high-resolution magnetic resonance imaging(3DT1 HR-MRI)data of patients with low-grade stenotic(wall and plaque location were analyzed.A total of 94 MCA plaques from 43 patients and 50 normal MCAs were analyzed.In the normal MCAs,WSS was lower at the ventral-inferior wall than at the dorsal-superior wall(proximal segment,pwall than at the outer wall of the MCA curve(pwall to the dorsal-superior wall in atherosclerotic MCAs was lower than that in normal MCAs(p=0.002).The WSS_(inmer-outer)ratio in atherosclerotic MCAs was lower than that in normal MCAs(p=0.002).Low WSS was associated with MCA atherosclerosis formation and occurred mainly at the ventral inferior wall,which was anatomically opposite the orifices of penetrating arteries,and at the inner wall of the MCA curve.Overall,the results were well consistent with the low WSS theory in atherosclerosis formation.The reconstructed WSS model is a promising novel method for assessing an individualized vascular profile once validated by further studies.

关键词： Intracranial atherosclerosis wall shear stress Atherosclerotic plaque High-resolution magnetic resonance imaging Computational fluid dynamics

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wall shear stress in intracranial aneurysms and adjacent arteries

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Neural Regeneration Research 2013年第11期8卷 1007-1015页

作者： Fuyu Wang Bainan Xu Zhenghui Sun Chen Wu Xiaojun Zhang Department of Neurosurgery Chinese PLA General Hospital College of Mechanical Engineering and Applied Electronics Technology Beijing University of Technology

Hemodynamic parameters play an important role in aneurysm formation and growth. However, it is difficult to directly observe a rapidly growing de novo aneurysm in a patient. To investigate possible associations between hemodynamic parameters and the formation and growth of intracranial aneurysms, the present study constructed a computational model of a case with an internal carotid artery aneurysm and an anterior communicating artery aneurysm, based on the CT angiography findings of a patient. To simulate the formation of the anterior communicating artery aneurysm and the growth of the internal carotid artery aneurysm, we then constructed a model that virtually removed the anterior communicating artery aneurysm, and a further two models that also progressively decreased the size of the internal carotid artery aneurysm. Computational simulations of the fluid dynamics of the four models were performed under pulsatile flow conditions, and wall shear stress was compared among the different models. In the three aneurysm growth models, increasing size of the aneurysm was associated with an increased area of low wall shear stress, a significant decrease in wall shear stress at the dome of the aneurysm, and a significant change in the wall shear stress of the parent artery. The wall shear stress of the anterior communicating artery remained low, and was significantly lower than the wall shear stress at the bifurcation of the internal carotid artery or the bifurcation of the middle cerebral artery. After formation of the anterior communicating artery aneurysm, the wall shear stress at the dome of the internal carotid artery aneurysm increased significantly, and the wall shear stress in the upstream arteries also changed significantly. These findings indicate that low wall shear stress may be associated with the initiation and growth of aneurysms, and that aneurysm formation and growth may influence hemodynamic parameters in the local and adjacent arteries.

关键词： neural regeneration wall shear stress hemodynamic parameters intracranial aneurysm fluid-solidcoupled model growth formation CT angiography second reconstruction multiple aneurysms numerical simulation grants-supported paper neuroregeneration

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Inner-outer decomposition of wall shear stress fluctuations in turbulent channels

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Theoretical & Applied Mechanics Letters 2022年第2期12卷 132-136页

作者： Limin Wang Ruifeng Hu Center for Particle-Laden Turbulence Key Laboratory of Mechanics on Disaster and Environment in Western ChinaMinistry of EducationCollege of Civil Engineering and MechanicsLanzhou UniversityLanzhou 730000China

Fluctuating wall shear stress in turbulent channel flows is decomposed into small-scale and large-scale components.The large-scale fluctuating wall shear stress is computed as the footprints of the outer turbulent motions,and the small-scale one is obtained by subtracting the large-scale one from the total,which fully remove the outer influences.We show that the statistics of the small-scale fluctuating wall shear stress is Reynolds number independent at the friction Reynolds number larger than 1000,while which is Reynolds number dependent or the low-Reynolds-number effect exists at the friction Reynolds number smaller than 1000.Therefore,a critical Reynolds number that defines the emergence of universal small-scale fluctuating wall shear stress is proposed to be 1000.The total and large-scale fluctuating wall shear stress intensities approximately follow logarithmic-linear relationships with Reynolds number,and empirical fitting expressions are given in this work.

关键词： Turbulent boundary layer wall shear stress Inner-outer decomposition

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Distribution of wall shear stress in carotid plaques using magnetic resonance imaging and computational fluid dynamics analysis： a preliminary study

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Chinese Medical Journal 2011年第10期124卷 1465-1469页

作者： JING Li-na GAO Pei-yi LIN Yan SUI Bin-bin QIN Hai-qiang MA Li XUE Jing Department of Radiology Affiliated Beijing Tiantan Hospital Capital Medical University Beijing 100050 China Department of Neurology Affiliated Beijing Tiantan Hospital Capital Medical University Beijing 100050 China

Background wall shear stress is an important factor in the destabilization of atherosclerotic plaques. The purpose of this study was to assess the distribution of wall shear stress in advanced carotid plaques using high resolution magnetic resonance imaging and computational fluid dynamics.Methods Eight diseased internal carotid arteries in seven patients were evaluated. High resolution magnetic resonance imaging was used to visualize the plaque structures, and the mechanic stress in the plaque was obtained by combining vascular imaging post-processing with computational fluid dynamics.Results wall shear stresses in the plaques in all cases were higher than those in control group. Maximal shear stresses in the plaques were observed at the top of plaque hills, as well as the shoulders of the plaques. Among them,the maximal shear stress in the ruptured plaque was observed in the rupture location in three cases and at the shoulder of fibrous cap in two cases. The maximal shear stress was also seen at the region of calcification, in thrombus region and in the thickest region of plaque in the other three cases, respectively.Conclusion Determination of maximal shear stress at the plaque may be useful for predicting the rupture location of the plaque and may play an important role in assessing plaque vulnerability.

关键词： atherosclerosis carotid artery computationalfluid dynamics magnetic resonance imaging wall shear stress

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Efficient calculation of fluid-induced wall shear stress within tissue engineering scaffolds by an empirical model

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Medicine in Novel Technology and Devices 2023年第2期18卷 267-271页

作者： Husham Ahmed Matthew Bedding-Tyrrell Davide Deganello Zhidao Xia Yi Xiong Feihu Zhao Zienkiewicz Centre for Computational Engineering and Department of Biomedical Engineering Faculty of Science&EngineeringSwansea UniversitySwanseaSA18ENUK Welsh Centre for Printing and Coating Faculty of Science and EngineeringSwansea UniversitySwanseaSA18ENUK Centre for Nanohealth Swansea University Medical School and Faculty of MedicineHealth and Life ScienceSwansea UniversitySwanseaSA35AUUK School of System Design and Intelligent Manufacturing Southern University of Science and TechnologyShenzhen518055China

Mechanical stimulation,such as fluid-induced wall shear stress(WSS),is known that can influence the cellular behaviours.Therefore,in some tissue engineering experiments in vitro,mechanical stimulation is applied via bioreactors to the cells in cell culturing to study cell physiology and pathology.In 3D cell culturing,porous scaffolds are used for housing the cells.It is known that the scaffold porous geometries can influence the scaffold permeability and internal WSS in a bioreactor(such as perfusion bioreactor).To calculate the WSS generated on cells within scaffolds,usually computational fluid dynamics(CFD)simulation is needed.However,the limitations of the computational method for WSS calculation are:(i)the high time cost of the CFD simulation(in particular for the highly irregular geometries);(ii)accessibility to the CFD model for some cell culturing experimentalists due to the knowledge gap.To address these limitations,this study aims to develop an empirical model for calculating the WSS based on scaffold permeability.This model can allow the tissue engineers to efficiently calculate the WSS generated within the scaffold and/or determine the bioreactor loading without performing the computational simulations.

关键词： wall shear stress Permeability Empirical model Tissue engineering scaffold Bioreactor

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Study of Effect of Boundary Conditions on Patient-Specific Aortic Hemodynamics

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Computer Modeling in Engineering & Sciences 2022年第4期131卷 31-47页

作者： Qingzhuo Chi Huimin Chen Shiqi Yang Lizhong Mu Changjin Ji Ying He Yong Luan Key Laboratory of Ocean Energy Utilization and Energy Conservation of Ministry of Education Dalian University of TechnologyDalian116024China School of Biomedical Engineering Capital Medical UniversityBeijing100069China Department of Anesthesiology The First Affiliated Hospital of Dalian Medical UniversityDalian116011China

Cardiovascular computational fluid dynamics(CFD)based on patient-specific modeling is increasingly used to predict changes in hemodynamic parameters before or after surgery/interventional treatment for aortic dissection(AD).This study investigated the effects of flow boundary conditions(BCs)on patient-specific aortic hemodynamics.We compared the changes in hemodynamic parameters in a type A dissection model and normal aortic model under different BCs:inflow from the auxiliary and truncated structures at aortic valve,pressure control and Windkessel model outflow conditions,and steady and unsteady inflow conditions.The auxiliary entrance remarkably enhanced the physiological authenticity of numerical simulations of flow in the ascending aortic cavity.Thus,the auxiliary entrance can well reproduce the injection flow fromthe aortic valve.In addition,simulations of the aortic model reconstructed with an auxiliary inflow structure and pressure control and the Windkessel model outflow conditions exhibited highly similar flow patterns and wall shear stress distribution in the ascending aorta under steady and unsteady inflow conditions.Therefore,the inflow structure at the valve plays a crucial role in the hemodynamics of the aorta.Under limited time and calculation cost,the steady-state study with an auxiliary inflow valve can reasonably reflect the blood flow state in the ascending aorta and aortic arch.With reasonable BC settings,cardiovascular CFD based on patient-specific ADmodels can aid physicians in noninvasive and rapid diagnosis.

关键词： Aortic dissection boundary condition valve wall shear stress patient-specific model

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Numerical simulation to study the impact of compliance mismatch between artificial and host blood vessel on hemodynamics

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Medicine in Novel Technology and Devices 2022年第3期15卷 115-123页

作者： Ting Cao Ziyi Jiang Huijing Zhao Ke-Qin Zhang Kai Meng College of Textile and Clothing Engineering Soochow University.No.178 Ganjiang RoadSuzhou215006PR China National Engineering Laboratory for Modern Silk(Suzhou).No.199 Ren'ai Road Industrial ParkSuzhou215123PR China

Small-diameter artificial blood vessels are prone to cause intimal hyperplasia(IH)after transplantation,which leads to restenosis and low long-term patency rates.The main biomechanical factor for IH formation is the compliance mismatch between the artificial and host blood vessels which can cause abnormal hemodynamics.Although there have been many studies on vascular compliance mismatches,however,little attention has been paid to the effect of the degree of compliance mismatch between graft and the host vessel on hemodynamics.At present,the research on compliance mismatch between the artificial and host blood vessels is still very limited,especially with regard to the specific impact of the compliance mismatch degree on hemodynamics.Therefore,three end-to-end anastomosis models(the compliance of the artificial blood vessel is lower than,similar to,and higher than that of the host blood vessel,called model 1,model 2,model 3,respectively)were constructed and simulated in this study.Simulation results showed that the radial displacement difference between the artificial and host blood vessels were 0.281 mm,0.183 mm and 0.485 mm in model 1,model 2 and model 3,respectively.A low-velocity recirculation zone near the distal anastomosis was formed in model 1 which resulted in excessively low TAWSS(9.261 E-5Pa)and high OSI(0.497).Similarly,a low-velocity recirculation zone near the proximal anastomosis was formed in model 3 and lead to low TAWSS(6.007 E-4Pa)and high OSI(0.480).However,there was no low-velocity recirculation zone near the anastomosis stoma in model 2.The results are instructive for the design and preparation of artificial blood vessels.

关键词： Numerical simulation Artificial blood vessel Compliance mismatch wall shear stress Oscillatory shear index

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Experimental and computational studies on the flow fields in aortic aneurysms associated with deployment of AAA stent-grafts

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Acta Mechanica Sinica 2007年第5期23卷 495-501页

作者： Xiwen Zhang Zhaohui Yao Yan Zhang Shangdong Xu Department of Engineering Mechanics Tsinghua University Beijing 100084 China Institute of Heart Pulmonary and Vascular Diseases Capital University of Medical Science Affiliated Beijing Anzhen Hospital Beijing 100029 China

Pulsatile flow fields in rigid abdominal aortic aneurysm （AAA） models were investigated numerically, and the simulation results are found in good agreement with particle image velocimetry （PIV） measurements. There are one or more vortexes in the AAA bulge, and a fairly high wall shear stress exists at the distal end, and thus the AAA is in danger of rupture. Medical treatment consists of inserting a vascular stent-graft in the AAA, which would decrease the blood impact to the inner walls and reduce wall shear stress so that the rupture could be prevented. A new computational model, based on porous medium model, was developed and results are documented. Therapeutic effect of the stent-graft was verified numerically with the new model.

关键词： Abdominal aortic aneurysm Numerical simulation Particle image velocimetry wall shear stress Stent-graft

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Finite element analysis of nitric oxide(NO) transport in system of permeable capillary and tissue

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Journal of Hydrodynamics 2018年第4期30卷 722-737页

作者：魏雅洁贺缨唐元梁母立众 School of Energy and Power Engineering Dalian University of Technology

The endothelial dysfunction and the unbalanced secretion of vasoactive substances are the main causes of the macro and micro vascular complications for patients with diabetic mellitus（DM）. This paper investigates the blood flow and the nitric oxide（NO） transport in a permeable capillary by using a finite element method. The computational domain consists of a permeable straight or bifurcated capillary and the surrounding tissue with different endothelial hydraulic permeability. The blood flow in the lumen of a capillary is assumed to be governed by the Stokes equation. The fluid flow in the surrounding tissue is simplified as the Darcy flow. The advection–diffusion reaction equation is employed to investigate the NO distribution in a lumen-tissue model, which is originated from the endothelial cells inside the capillary wall. The characteristic Galerkin method is employed for the discretization of the advection-diffusion reaction equation. The simulated results show that the NO transport is effectively affected by different hydraulic permeabilities due to the changes of the blood velocity. When the hydraulic permeability increases considerably, the NO concentration（[NO]） in the whole domain decreases accordingly. Moreover, the NO concentration increases in the area after the bifurcation of the capillary owing to the convective effect. It is also shown that even if the NO production by the endothelial cells is enhanced, the increase of the convection inside the vessel may reduce the endothelial NO concentration. As a signal transduction molecule, the spatial location with discriminating NO distribution may be useful for determining the position of the microangiopathy in the DM.

关键词： Hydraulic permeability mass transport finite element method wall shear stress Nitric Oxide

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