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Teymoori M, Sadeghi MR, Rabbani M, Jahangiri M, Rahimi-gorji M. Effect of Extended Lipid Core on the Hemodynamic Parameters: A Fluid-Structure Interaction Approach. Appl Bionics Biomech 2022; 2022:1-14. [PMID: 35342456 PMCID: PMC8947935 DOI: 10.1155/2022/2047549] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2021] [Accepted: 02/28/2022] [Indexed: 11/17/2022] Open
Abstract
Myocardial infarction is one of the leading causes of death in the developed countries. A majority of myocardial infarctions are caused by the rupture of coronary artery plaques. In order to achieve a better understanding of the effect of the extension of the lipid core into the artery wall on the change of flow field and its effect on plaque vulnerability, we have studied the hemodynamic parameters by utilizing a finite element method and taking into account the fluid-structure interaction (FSI). Four groups of stenosis models with different sizes of lipid core were used in the study. The fully developed pulsatile velocity profile of the right coronary artery was used as the inlet boundary condition, and the pressure pulse was applied as the outlet boundary condition. The non-Newtonian Carreau model was used to simulate the non-Newtonian behavior of blood. Results indicate that the extension of the lipid core into the artery wall influences the flow field; subsequently, creates favorable conditions for additional development of the lipid core which can lead to a higher risk of plaque rupture.
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Peng C, Liu J, He W, Qin W, Yuan T, Kan Y, Wang K, Wang S, Shi Y. Numerical simulation in the abdominal aorta and the visceral arteries with or without stenosis based on 2D PCMRI. Int J Numer Method Biomed Eng 2022; 38:e3569. [PMID: 34967124 DOI: 10.1002/cnm.3569] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/13/2021] [Revised: 12/10/2021] [Accepted: 12/27/2021] [Indexed: 06/14/2023]
Abstract
It is important to obtain accurate boundary conditions (BCs) in hemodynamic simulations. This article aimed to improve the accuracy of BCs in computational fluid dynamics (CFD) simulation and analyze the differences in hemodynamics between healthy volunteers and patients with visceral arterial stenosis (VAS). The geometric models of seven cases were reconstructed using the magnetic resonance angiogram (MRA) or computed tomography angiogram (CTA) imaging data. The physiological flow waveforms obtained from 2D Phase Contrast Magnetic Resonance Imaging (PCMRI) were imposed on the aortic inlet and the visceral arteries' outlets. The individualized RCR values of the three-element Windkessel model were imposed on the aortic outlet. CFD simulations were run in the open-source software: svSolver. Two specific time points were selected to compare the hemodynamics of healthy volunteers and patients with VAS. The results suggested that blood in the stenotic visceral arteries flowed at high speed throughout the cardiac cycle. The low pressure is distributed at stenotic lesions. The wall shear stress (WSS) reached 4 Pa near stenotic locations. The low time average wall shear stress (TAWSS), high oscillatory shear index (OSI), and high relative residence time (RRT) concentrated in the abdominal aorta. Besides, the ratios of the areas with low TAWSS, high OSI, and high RRT to the computational domain were higher in patients with VAS than which in the healthy volunteers. The individualized BCs were used for hemodynamic simulations and results suggest that patients with stenosis have a higher risk of blood retention and atherosclerosis formation in the abdominal aorta.
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Affiliation(s)
- Chen Peng
- Department of Aeronautics and Astronautics, Institute of Biomechanics, Fudan University, Shanghai, China
| | - Junzhen Liu
- Department of Radiology, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Wei He
- Department of Vascular Surgery, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Wang Qin
- Department of Aeronautics and Astronautics, Institute of Biomechanics, Fudan University, Shanghai, China
| | - Tong Yuan
- Department of Vascular Surgery, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Yuanqing Kan
- Department of Vascular Surgery, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Keqiang Wang
- Institute of Panvascular Medicine, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Shengzhang Wang
- Department of Aeronautics and Astronautics, Institute of Biomechanics, Fudan University, Shanghai, China
- Institute of Biomedical Engineering Technology, Academy for Engineering and Technology, Fudan University, Shanghai, China
| | - Yun Shi
- Department of Vascular Surgery, Zhongshan Hospital, Fudan University, Shanghai, China
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Chen Y, Zhang S, Chen Y, Lao Y, Huang X, Huang X, Liao Q, Li Y. Rupture Risk Assessment of Cervical Spinal Manipulations on Carotid Atherosclerotic Plaque by a 3D Fluid-Structure Interaction Model. Biomed Res Int 2021; 2021:8239326. [PMID: 33490277 DOI: 10.1155/2021/8239326] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/18/2020] [Revised: 12/12/2020] [Accepted: 12/21/2020] [Indexed: 11/17/2022]
Abstract
Method The FSI model, based on MRI data of an atherosclerosis patient, was used to simulate the deformations of the plaque and lumen during the process of two kinds of typical cSMT (the high-speed, low-amplitude spinal manipulation and the cervical rotatory manipulation). The biomechanical parameters were recorded, such as the highest wall shear stress (WSS), the maximum plaque wall stress (PWS), the wall tensile stress (Von mises stress, VWTS), and the strain. Result The max_WSS was 33.77 kPa in the most extensive deformation. The highest WSS region on the plaque surface was also the highest PWS region. The max_PWS in a 12% stretch was 55.11 kPa, which was lower than the rupture threshold. The max_VWTS of the cap in 12% stretch which approached the fracture stress level was 116.75 kPa. Moreover, the vessel's max_VWTS values in 10% and 12% stretch were 554.21 and 855.19 kPa. They were higher than the fracture threshold, which might cause media fracture. Meanwhile, the 7% stretched strain was 0.29, closed to the smallest experimental green strains at rupture. Conclusion The carotid arteries' higher stretch generated the higher stress level of the plaque. Cervical rotatory manipulation might cause plaque at a high risk of rupture in deformation after 12% stretch and more. Lower deformation of the plaque and artery caused by the high-speed, low-amplitude spinal manipulation might be safer.
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Xu L, Chen X, Cui M, Ren C, Yu H, Gao W, Li D, Zhao W. The improvement of the shear stress and oscillatory shear index of coronary arteries during Enhanced External Counterpulsation in patients with coronary heart disease. PLoS One 2020; 15:e0230144. [PMID: 32191730 PMCID: PMC7082042 DOI: 10.1371/journal.pone.0230144] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Accepted: 02/23/2020] [Indexed: 12/25/2022] Open
Abstract
Background Enhanced External Counterpulsation (EECP) can chronically relieve ischemic chest pain and improve the prognosis of coronary heart disease (CHD). Despite its role in mitigating heart complications, EECP and the mechanisms behind its therapeutic nature, such as its effects on blood flow hemodynamics, are still not fully understood. This study aims to elucidate the effect of EECP on significant hemodynamic parameters in the coronary arterial tree. Methods A finite volume method was used in conjunction with the inlet pressure wave (surrogated by the measured aortic pressure) before and during EECP and outlet flow resistance, assuming the blood as newtonian fluid. The time-average wall shear stress (TAWSS) and oscillatory shear index (OSI) were determined from the flow field. Results Regardless of the degree of vascular stenosis, hemodynamic conditions and flow patterns could be improved during EECP. In comparison with the original tree, the tree with a severe stenosis (75% area stenosis) demonstrated more significant improvement in hemodynamic conditions and flow patterns during EECP, with surface area ratio of TAWSS risk area (SAR-TAWSS) reduced from 12.3% to 6.7% (vs. SAR-TAWSS reduced from 7.2% to 5.6% in the original tree) and surface area ratio of OSI risk area (SAR-OSI) reduced from 6.8% to 2.5% (vs. SAR-OSI of both 0% before and during EECP in the original tree because of mild stenosis). Moreover, it was also shown that small ratio of diastolic pressure (D) and systolic pressure (S) (D/S) could only improve the hemodynamic condition mildly. The SAR-TAWSS reduction ratio significantly increased as D/S became larger. Conclusions A key finding of the study was that the improvement of hemodynamic conditions along the LMCA trees during EECP became more significant with the increase of D/S and the severity degree of stenoses at the bifurcation site. These findings have important implications on EECP as adjuvant therapy before or after percutaneous coronary intervention (PCI) in patients with diffuse atherosclerosis.
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Affiliation(s)
- Ling Xu
- NHC Key Laboratory of Cardiovascular Molecular Biology and Regulatory Peptides, Department of Cardiology, Peking University Third Hospital, Beijing, China
| | - Xi Chen
- School of Biomedical Engineering, Capital Medical University, Beijing, China
| | - Ming Cui
- NHC Key Laboratory of Cardiovascular Molecular Biology and Regulatory Peptides, Department of Cardiology, Peking University Third Hospital, Beijing, China
| | - Chuan Ren
- NHC Key Laboratory of Cardiovascular Molecular Biology and Regulatory Peptides, Department of Cardiology, Peking University Third Hospital, Beijing, China
| | - Haiyi Yu
- NHC Key Laboratory of Cardiovascular Molecular Biology and Regulatory Peptides, Department of Cardiology, Peking University Third Hospital, Beijing, China
| | - Wei Gao
- NHC Key Laboratory of Cardiovascular Molecular Biology and Regulatory Peptides, Department of Cardiology, Peking University Third Hospital, Beijing, China
| | - Dongguo Li
- School of Biomedical Engineering, Capital Medical University, Beijing, China
- * E-mail: (DGL); (WZ)
| | - Wei Zhao
- NHC Key Laboratory of Cardiovascular Molecular Biology and Regulatory Peptides, Department of Cardiology, Peking University Third Hospital, Beijing, China
- * E-mail: (DGL); (WZ)
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Chen X, Gao Y, Lu B, Jia X, Zhong L, Kassab GS, Tan W, Huo Y. Hemodynamics in Coronary Arterial Tree of Serial Stenoses. PLoS One 2016; 11:e0163715. [PMID: 27685989 PMCID: PMC5042402 DOI: 10.1371/journal.pone.0163715] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2016] [Accepted: 09/13/2016] [Indexed: 11/18/2022] Open
Abstract
Serial segmental narrowing frequently occurs in humans, which alters coronary hemodynamics and further affects atherosclerotic progression and plaque formation. The objective of this study was to understand the distribution of hemodynamic parameters in the epicardial left main coronary arterial (LMCA) tree with serial stenoses reconstructed from patient computer tomography angiography (CTA) images. A finite volume method was used in conjunction with the inlet pressure wave and outlet flow resistance. The time-averaged wall shear stress (TAWSS) and oscillatory shear index (OSI) were determined from the flow field. A stenosis at a mother vessel mainly deteriorated the hemodynamics near the bifurcation while a stenosis at a daughter vessel affected the remote downstream bifurcation. In comparison with a single stenosis, serial stenoses increased the peak pressure gradient along the main trunk of the epicardial left anterior descending arterial tree by > 50%. An increased distance between serial stenoses further increased the peak pressure gradient. These findings have important implications on the diagnosis and treatment of serial coronary stenoses.
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Affiliation(s)
- Xi Chen
- Department of Mechanics and Engineering Science, College of Engineering, Peking University, Beijing, China
- State Key Laboratory for Turbulence and Complex Systems, College of Engineering, Peking University, Beijing, China
- School of Biomedical Engineering, Capital Medical University, Beijing, China
| | - Yang Gao
- State Key Laboratory of Cardiovascular Disease, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Bin Lu
- State Key Laboratory of Cardiovascular Disease, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Xinwei Jia
- Department of Cardiology, Affiliated hospital of Hebei University, Hebei University, Baoding, China
| | - Liang Zhong
- National Heart Center Singapore, Singapore, Singapore
- Duke-NUS Graduate Medical School Singapore, Singapore, Singapore
| | - Ghassan S. Kassab
- California Medical Innovations Institute, San Diego, California, United States of America
| | - Wenchang Tan
- Department of Mechanics and Engineering Science, College of Engineering, Peking University, Beijing, China
- State Key Laboratory for Turbulence and Complex Systems, College of Engineering, Peking University, Beijing, China
- * E-mail: (YH); (WT)
| | - Yunlong Huo
- Department of Mechanics and Engineering Science, College of Engineering, Peking University, Beijing, China
- State Key Laboratory for Turbulence and Complex Systems, College of Engineering, Peking University, Beijing, China
- * E-mail: (YH); (WT)
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Xiong H, Liu X, Tian X, Pu L, Zhang H, Lu M, Huang W, Zhang YT. A numerical study of the effect of varied blood pressure on the stability of carotid atherosclerotic plaque. Biomed Eng Online 2014; 13:152. [PMID: 25413300 PMCID: PMC4277844 DOI: 10.1186/1475-925x-13-152] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2014] [Accepted: 10/22/2014] [Indexed: 12/18/2022] Open
Abstract
Background Blood pressure (BP) is associated with early atherosclerosis and plaque
rupture because the BP variability can significantly affect the blood flow
velocity and shear stress over the plaque. However, the mechanical response of BP
variability to the plaque remains unclear. Therefore, we investigated the
correlation between different maximum systolic blood pressure (SBP) and the stress
distribution on plaque, as well as the stress over the plaque and blood velocity
around the plaque using different BP variations, which are the BP variability in
different phases during one cardiac cycle and beat-to-beat BP variability. Method We established a two-dimensional artery model with stenosis at the degree of
62.5%. Eight combinations of pulsatile pressure gradients between the inflow and
outflow were implemented at the model. Three levels of fibrous cap thickness were
taken into consideration to investigate the additional effect on the BP
variability. Wall shear stress and stress/strain distribution over the plaque were
derived as well as the oscillation shear index (OSI) to analyze the impact of the
changing rate of BP. Result The stresses at diastole were 2.5% ± 1.8% lower than that at systole under the
same pressure drop during one cycle. It was also found that elevated SBP might
cause the immediate increment of stress in the present cycle (292% ± 72.3%), but
slight reduction in the successive cycle (0.48% ± 0.4%). Conclusion The stress/strain distribution over the plaque is sensitive to the BP
variability during one cardiac cycle, and the beat-to-beat BP variability could
cause considerable impact on the progression of atherosclerosis in
long-term.
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Affiliation(s)
| | | | | | | | - Heye Zhang
- Key Lab of Health Informatics of Chinese Academy of Sciences, Shenzhen, China.
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Pedrigi RM, de Silva R, Bovens SM, Mehta VV, Petretto E, Krams R. Thin-Cap Fibroatheroma Rupture Is Associated With a Fine Interplay of Shear and Wall Stress. Arterioscler Thromb Vasc Biol 2014; 34:2224-31. [DOI: 10.1161/atvbaha.114.303426] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
In this review, we summarized the effect of mechanical factors (shear and wall stress) on thin-cap fibroatheroma formation and rupture. To make this review understandable for a biology-oriented audience, we start with detailed definitions of relevant mechanical metrics. We then describe how biomechanics has supported histopathologic efforts to understand the basis of plaque rupture. In addition to plaque rupture, biomechanics also contributes toward the progression of thin-cap fibroatheroma through a multitude of reported mechanobiological mechanisms. We thus propose a new mechanism whereby both shear stress and wall stress interact to create thin-cap fibroatheromas. Specifically, when regions of certain blood flow and wall mechanical stimuli coincide, they synergistically create inflammation within the cellular environment that can lead to thin-cap fibroatheroma rupture. A consequence of this postulate is that local shear stress is not sufficient to cause rupture, but it must coincide with regions of local tissue stiffening and stress concentrations that can occur during plaque progression. Because such changes to the wall mechanics occur over a micrometer scale, high spatial resolution imaging techniques will be necessary to evaluate this hypothesis and ultimately predict plaque rupture in a clinical environment.
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Affiliation(s)
- Ryan M. Pedrigi
- From the Department of Bioengineering, Imperial College London, London, United Kingdom (R.M.P., S.M.B., V.V.M., R.K.); NHLI, Imperial College London and NIHR Cardiovascular Biomedical Research Unit, Royal Brompton and Harefield NHS Foundation Trust, London, United Kingdom (R.d.S.); and MRC-Clinical Sciences Centre, Imperial College London, London, United Kingdom (E.P.)
| | - Ranil de Silva
- From the Department of Bioengineering, Imperial College London, London, United Kingdom (R.M.P., S.M.B., V.V.M., R.K.); NHLI, Imperial College London and NIHR Cardiovascular Biomedical Research Unit, Royal Brompton and Harefield NHS Foundation Trust, London, United Kingdom (R.d.S.); and MRC-Clinical Sciences Centre, Imperial College London, London, United Kingdom (E.P.)
| | - Sandra M. Bovens
- From the Department of Bioengineering, Imperial College London, London, United Kingdom (R.M.P., S.M.B., V.V.M., R.K.); NHLI, Imperial College London and NIHR Cardiovascular Biomedical Research Unit, Royal Brompton and Harefield NHS Foundation Trust, London, United Kingdom (R.d.S.); and MRC-Clinical Sciences Centre, Imperial College London, London, United Kingdom (E.P.)
| | - Vikram V. Mehta
- From the Department of Bioengineering, Imperial College London, London, United Kingdom (R.M.P., S.M.B., V.V.M., R.K.); NHLI, Imperial College London and NIHR Cardiovascular Biomedical Research Unit, Royal Brompton and Harefield NHS Foundation Trust, London, United Kingdom (R.d.S.); and MRC-Clinical Sciences Centre, Imperial College London, London, United Kingdom (E.P.)
| | - Enrico Petretto
- From the Department of Bioengineering, Imperial College London, London, United Kingdom (R.M.P., S.M.B., V.V.M., R.K.); NHLI, Imperial College London and NIHR Cardiovascular Biomedical Research Unit, Royal Brompton and Harefield NHS Foundation Trust, London, United Kingdom (R.d.S.); and MRC-Clinical Sciences Centre, Imperial College London, London, United Kingdom (E.P.)
| | - Rob Krams
- From the Department of Bioengineering, Imperial College London, London, United Kingdom (R.M.P., S.M.B., V.V.M., R.K.); NHLI, Imperial College London and NIHR Cardiovascular Biomedical Research Unit, Royal Brompton and Harefield NHS Foundation Trust, London, United Kingdom (R.d.S.); and MRC-Clinical Sciences Centre, Imperial College London, London, United Kingdom (E.P.)
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Gao H, Long Q, Das SK, Sadat U, Graves M, Gillard JH, Li ZY. Stress analysis of carotid atheroma in transient ischemic attack patients: evidence for extreme stress-induced plaque rupture. Ann Biomed Eng 2011; 39:2203-12. [PMID: 21544675 DOI: 10.1007/s10439-011-0314-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2010] [Accepted: 04/15/2011] [Indexed: 11/26/2022]
Abstract
Plaque rupture has been considered to be the result of its structural failure. The aim of this study is to suggest a possible link between higher stresses and rupture sites observed from in vivo magnetic resonance imaging (MRI) of transient ischemic attack (TIA) patients, by using stress analysis methods. Three patients, who had recently suffered a TIA, underwent in vivo multi-spectral MR imaging. Based on plaque geometries reconstructed from the post-rupture status, six pre-rupture plaque models were generated for each patient dataset with different reconstructions of rupture sites to bridge the gap of fibrous cap from original MRI images. Stress analysis by fluid structure interaction simulation was performed on the models, followed by analysis of local stress concentration distribution and plaque rupture sites. Furthermore, the sensitivity of stress analysis to the pre-rupture plaque geometry reconstruction was examined. Local stress concentrations were found to be located at the plaque rupture sites for the three subjects studied. In the total of 18 models created, the locations of the stress concentration regions were similar in 17 models in which rupture sites were always associated with high stresses. The local stress concentration region moved from circumferential center to the shoulder region (slightly away from the rupture site) for a case with a thick fibrous cap. Plaque wall stress level in the rupture locations was found to be much higher than the value in non-rupture locations. The good correlation between local stress concentrations and plaque rupture sites, and generally higher plaque wall stress level in rupture locations in the subjects studied could provide indirect evidence for the extreme stress-induced plaque rupture hypothesis. Local stress concentration in the plaque region could be one of the factors contributing to plaque rupture.
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Affiliation(s)
- Hao Gao
- Brunel Institute for Bioengineering, Brunel University, Uxbridge, Middlesex, UB8 3PH, UK
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