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Wang L, Jiang X, Zhang K, Chen K, Wu P, Li X. A hemodynamic analysis of energy loss in abdominal aortic aneurysm using three-dimension idealized model. Front Physiol 2024; 15:1330848. [PMID: 38312315 PMCID: PMC10834748 DOI: 10.3389/fphys.2024.1330848] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2023] [Accepted: 01/05/2024] [Indexed: 02/06/2024] Open
Abstract
Objective: The aim of this study is to perform specific hemodynamic simulations of idealized abdominal aortic aneurysm (AAA) models with different diameters, curvatures and eccentricities and evaluate the risk of thrombosis and aneurysm rupture. Methods: Nine idealized AAA models with different diameters (3 cm or 5 cm), curvatures (0° or 30°) and eccentricities (centered on or tangent to the aorta), as well as a normal model, were constructed using commercial software (Solidworks; Dassault Systemes S.A, Suresnes, France). Hemodynamic simulations were conducted with the same time-varying volumetric flow rate extracted from the literature and 3-element Windkessel model (3 EWM) boundary conditions were applied at the aortic outlet. Several hemodynamic parameters such as time-averaged wall shear stress (TAWSS), oscillatory shear index (OSI), relative residence time (RRT), endothelial cell activation potential (ECAP) and energy loss (EL) were obtained to evaluate the risk of thrombosis and aneurysm rupture under different conditions. Results: Simulation results showed that the proportion of low TAWSS region and high OSI region increases with the rising of aneurysm diameter, whereas decreases in the curvature and eccentric models of the corresponding diameters, with the 5 cm normal model having the largest low TAWSS region (68.5%) and high OSI region (40%). Similar to the results of TAWSS and OSI, the high ECAP and high RRT areas were largest in the 5 cm normal model, with the highest wall-averaged value (RRT: 5.18 s, ECAP: 4.36 Pa-1). Differently, the increase of aneurysm diameter, curvature, and eccentricity all lead to the increase of mean flow EL and turbulent EL, such that the highest mean flow EL (0.82 W · 10-3) and turbulent EL (1.72 W · 10-3) were observed in the eccentric 5 cm model with the bending angle of 30°. Conclusion: Collectively, increases in aneurysm diameter, curvature, and eccentricity all raise mean flow EL and turbulent flow EL, which may aggravate the damage and disturbance of flow in aneurysm. In addition, it can be inferred by conventional parameters (TAWSS, OSI, RRT and ECAP) that the increase of aneurysm diameter may raise the risk of thrombosis, whereas the curvature and eccentricity appeared to have a protective effect against thrombosis.
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Affiliation(s)
- Lulu Wang
- Department of Vascular Surgery, Nanjing Drum Tower Hospital, Affiliated Hospital of Medical School, Nanjing University, Nanjing, China
| | - Xudong Jiang
- Department of Vascular Surgery, Nanjing Drum Tower Hospital, Affiliated Hospital of Medical School, Nanjing University, Nanjing, China
| | - Kejia Zhang
- Artificial Organ Technology Laboratory, School of Mechanical and Electrical Engineering, Soochow University, Suzhou, China
| | - Kai Chen
- Artificial Organ Technology Laboratory, School of Mechanical and Electrical Engineering, Soochow University, Suzhou, China
| | - Peng Wu
- School of Mechanical Engineering, Jiangsu Key Laboratory for Design and Manufacture of Micro-Nano Biomedical Instruments, Southeast University, Nanjing, China
| | - Xiaoqiang Li
- Department of Vascular Surgery, Nanjing Drum Tower Hospital, Affiliated Hospital of Medical School, Nanjing University, Nanjing, China
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He F, Li M, Hua L, Guo T. A hemodynamic model of artery bypass graft considering microcirculation function. Biomed Mater Eng 2024; 35:237-248. [PMID: 38461499 DOI: 10.3233/bme-230145] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/12/2024]
Abstract
BACKGROUND The incidence of arterial stenosis is increasing year by year. In order to better diagnose and treat arterial stenosis, numerical simulation technology has become a popular method. OBJECTIVE A novel model is constructed to investigate the influence of microcirculation on the hemodynamics of artery bypass graft. METHODS In this paper, a severely narrow artery bypass graft model is considered. The geometric shape includes a narrow artery tube and a bypass graft of the same diameter with a 45° suture angle. The fluid-structure interaction model is considered by finite element numerical calculation, and the flow is simulated with microcirculation as the outlet boundary condition. The changes of blood flow velocity, pressure and wall shear stress are analyzed. RESULTS The results show that blood almost entirely flows into the graft tube and there is no recirculation area at the anastomosis. CONCLUSION The artery bypass graft model considering microcirculation function could simulate the physiological characteristics of blood flow more reasonably, and it provide helps for clinicians to diagnose and treat arterial stenosis.
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Affiliation(s)
- Fan He
- School of Science, Beijing University of Civil Engineering and Architecture, Beijing, China
| | - Minru Li
- School of Science, Beijing University of Civil Engineering and Architecture, Beijing, China
| | - Lu Hua
- Thrombosis Center, National Clinical Research Center for Cardiovascular Diseases, 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
| | - Tingting Guo
- Thrombosis Center, National Clinical Research Center for Cardiovascular Diseases, 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
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Ma W, Cheng Z, Chen X, Huang C, Yu G, Chen G. Multiphase Flow Hemodynamic Evaluation of Vertebral Artery Stenosis Lesions and Plaque Stability. Biomed Mater Eng 2023; 34:247-260. [PMID: 36245366 DOI: 10.3233/bme-221436] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
BACKGROUND Atherosclerosis is one of the main causes of vertebral artery stenosis, which reduces blood supply to the posterior circulation, resulting in cerebral infarction or death. OBJECTIVE To investigate stenosis rates and locations on the development of vertebral artery plaques. METHODS Stenosis models with varying degrees and positions of stenosis were established. The stenosis area was comprehensively analyzed using multiphase flow numerical simulation. Wall shear stress (WSS), blood flow velocity, and red blood cell (RBC) volume fraction were calculated. RESULTS Blood flow velocity in 30-70% stenosis of each segment tended to increase significantly higher than normal. Downstream of 50% stenosis exhibited turbulent flow; downstream of 70% displayed reflux. Severe stenosis increases the WSS and distribution area. The mixed area of high and low WSS appeared downstream of the stenosis. The RBC volume fraction at the stenosis increased (maximum value: 0.487 at 70% stenosis in the V4), which was 1.08 times the normal volume fraction. Turbulent and backflow regions exhibited complex RBC volume fraction distributions. CONCLUSION Flow velocity, WSS, and RBC volume fraction at the stenosis increase with stenosis severity, increasing plaque shedding. Narrow downstream spoiler and reflux areas possess low WSS and high erythrocyte volume fractions, accelerating plaque growth.
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Affiliation(s)
- Wei Ma
- Mudanjiang Medical University, Heilongjiang, Mudanjiang, China
| | - Zhiguo Cheng
- Mudanjiang Medical University, Heilongjiang, Mudanjiang, China
| | - Xiaoqin Chen
- Mudanjiang Medical University, Heilongjiang, Mudanjiang, China
| | - Chengdu Huang
- Mudanjiang Medical University, Heilongjiang, Mudanjiang, China
| | - Guanghao Yu
- Mudanjiang Medical University, Heilongjiang, Mudanjiang, China
| | - Guangxin Chen
- Mudanjiang Medical University, Heilongjiang, Mudanjiang, China
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Li D, Zeng X, Wang J, Yuan D, Zheng T. Effects of different bypass surgeries on LSA revascularization in patients with left subclavian occlusion. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2022; 38:e3636. [PMID: 35778375 DOI: 10.1002/cnm.3636] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2022] [Revised: 06/01/2022] [Accepted: 06/26/2022] [Indexed: 02/05/2023]
Abstract
INTRO Left subclavian artery bypass surgery is mainly carried out for patients with severe left subclavian occlusion. This paper aimed to evaluate the hemodynamic effects of different surgical bypass modes on left subclavian artery revascularization. METHODS Three-dimensional models of the aorta were reconstructed from CTA images of a patient with left subclavian artery occlusion, a patient with type B aortic dissection with left subclavian artery coverage during thoracic endovascular aortic repair, and a healthy 74 year-old man, resulting in six modes for each person: healthy left subclavian artery mode, left subclavian artery occlusion mode and four bypass modes. Hemodynamic parameters, including flow field, flow distribution, pressure gradient, and wall shear stress, were calculated using computational fluid dynamics. RESULTS After left subclavian artery bypass surgery, distal left subclavian artery blood flow resulting from left common carotid artery to distal left subclavian artery bypass was 100% of that in the healthy mode, while the other modes yielded flows at least 91%. Moreover, reversed flow only completely disappeared with left common carotid artery to distal left subclavian artery bypass, whereas reverse flow was observed in the other three modes in early systole. CONCLUSION Left common carotid artery to distal left subclavian artery bypass can effectively reduce reverse blood flow in the left vertebral artery, and it is a feasible, effective, and safe option for left subclavian artery revascularization in patients with left subclavian occlusion.
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Affiliation(s)
- Da Li
- Department of Applied Mechanics, Sichuan University, Chengdu, China.,Yibin Institute of Industrial Technology, Sichuan University Yibin Park, Yibin, China
| | - Xiangguo Zeng
- Department of Applied Mechanics, Sichuan University, Chengdu, China
| | - Jiarong Wang
- Department vascular surgery of West China Hospital, Sichuan University, Chengdu, China
| | - Ding Yuan
- Department vascular surgery of West China Hospital, Sichuan University, Chengdu, China
| | - Tinghui Zheng
- Department of Applied Mechanics, Sichuan University, Chengdu, China.,Yibin Institute of Industrial Technology, Sichuan University Yibin Park, Yibin, China
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Jiang X, Cao H, Zhang Z, Zheng T, Li X, Wu P. A Hemodynamic Analysis of the Thrombosis Within Occluded Coronary Arterial Fistulas With Terminal Aneurysms Using a Blood Stasis Model. Front Physiol 2022; 13:906502. [PMID: 35677091 PMCID: PMC9169043 DOI: 10.3389/fphys.2022.906502] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2022] [Accepted: 05/04/2022] [Indexed: 11/21/2022] Open
Abstract
Objective: The aim of this study is to numerically evaluate thrombosis risk within occluded coronary arterial fistulas (CAF) with terminal aneurysms, and provide guidance in choosing occlusion positions, with clinical observations as reference. Method: Four patients with CAF were studied, with different occlusion positions in actual treatments. Hemodynamics simulations were conducted, with blood residue predicted using the blood stasis model. Three types of models (untreated model, aneurysm-reserved model and aneurysm-removed model) were studeid for each patient. Four metrics, i.e., proportion of high oscillatory shear index (OSI), area of high OSI, old blood volume fraction (OBVF)) and old blood volume (OBV) was obtained to distinguish the thrombosis risk of different treatments (proximal or distal occlusion), comparing with the follow-up CTA. Results: For all the postopertive models, the high OBVF, high OSI(>0.3) and low time-averaged wall shear stress (TAWSS) regions were mainly at the distal fistula, indicating these regions were prone to thrombosis. The regions where blood residue remains are roughly regions of high OSI, corresponding well with clinical observations. In contrast, TAWSS failed to distinguish the difference in thrombosis risk. Absolute values (area of high OSI, OBV) can better reflect the degree of thrombosis risk between treatment types compared with percentage values (proportion of high OSI, OBVF). By comparing with the actual clinical treatments and observations, the OBV is superior to the area of high OSI in determining treatment type. Conclusion: The OBV, a volumetric parameter for blood stasis, can better account for the CAF thrombosis and reflect the degree of blood stasis compared with OSI or TAWSS, is a more appropriate metric for thrombosis in the fistula. Together with morphological parameters, the OBV could guide clinicians to formulate more appropriate surgical plans, which is of great significance for the preoperative evaluation and treatment prognosis of CAF patients.
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Affiliation(s)
- Xudong Jiang
- Artificial Organ Technology Laboratory, School of Mechanical and Electric Engineering, Soochow University, Suzhou, China
- Department of Vascular Surgery, Nanjing Drum Tower Hospital Clinical College of Traditional Chinese and Western Medicine, Nanjing University of Chinese Medicine, Nanjing, China
| | - Haoyao Cao
- College of Architecture and Environmental Engineering, Sichuan University, Chengdu, China
- Sichuan University Yibin Park/Yibin Institute of Industrial Technology, Yibin, China
| | - Zijian Zhang
- Artificial Organ Technology Laboratory, School of Mechanical and Electric Engineering, Soochow University, Suzhou, China
| | - Tinghui Zheng
- College of Architecture and Environmental Engineering, Sichuan University, Chengdu, China
- Sichuan University Yibin Park/Yibin Institute of Industrial Technology, Yibin, China
| | - Xiaoqiang Li
- Department of Vascular Surgery, Nanjing Drum Tower Hospital Clinical College of Traditional Chinese and Western Medicine, Nanjing University of Chinese Medicine, Nanjing, China
| | - Peng Wu
- Artificial Organ Technology Laboratory, School of Mechanical and Electric Engineering, Soochow University, Suzhou, China
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Dutra RF, Zinani FSF, Rocha LAO, Biserni C. Effect of non-Newtonian fluid rheology on an arterial bypass graft: A numerical investigation guided by constructal design. COMPUTER METHODS AND PROGRAMS IN BIOMEDICINE 2021; 201:105944. [PMID: 33535083 DOI: 10.1016/j.cmpb.2021.105944] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/03/2020] [Accepted: 01/12/2021] [Indexed: 06/12/2023]
Abstract
In post-operative scenarios of arterial graft surgeries to bypass coronary artery stenosis, fluid dynamics plays a crucial role. Problems such as intimal hyperplasia have been related to fluid dynamics and wall shear stresses near the graft junction. This study focused on the question of the use of Newtonian and non-Newtonian models to represent blood in this type of problem in order to capture important flow features, as well as an analysis of the performance of geometry from the view of Constructive Theory. The objective of this study was to investigate the effects rheology on the steady-state flow and on the performance of a system consisting of an idealized version of a partially obstructed coronary artery and bypass graft. The Constructal Design Method was employed with two degrees of freedom: the ratio between bypass and artery diameters and the junction angle at the bypass inlet. The flow problem was solved numerically using the Finite Volume Method with blood modeled employing the Carreau equation for viscosity. The Computational Fluid Dynamics model associated with the Sparse Grid method generated eighteen response surfaces, each representing a severe stenosis degree of 75% for specific combinations of rheological parameters, dimensionless viscosity ratio, Carreau number and flow index at two distinct Reynolds numbers of 150 and 250. There was a considerable dependence of the pressure drop on rheological parameters. For the two Reynolds numbers studied, the Newtonian case presented the lowest value of the dimensionless pressure drop, suggesting that the choice of applying Newtonian blood may underestimate the value of pressure drop in the system by about 12.4% (Re =150) and 7.8% (Re = 250). Even so, results demonstrated that non-Newtonian rheological parameters did not influence either the shape of the response surfaces or the optimum bypass geometry, which consisted of a diameter ratio of 1 and junction angle of 30°. However, the viscosity ratio and the flow index had the greatest impact on pressure drop, recirculation zones and wall shear stress. Rheological parameters also affected the recirculation zones downstream of stenosis, where intimal hyperplasia is more prevalent. Newtonian and most non-Newtonian results had similar wall shear stresses, except for the non-Newtonian case with high viscosity ratio. In the view of Constructal Design, the geometry of best performance was independent of the rheological model. However, rheology played an important role on pressure drop and flow dynamics, allowing the prediction of recirculation zones that were not captured by a Newtonian model.
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Affiliation(s)
- R F Dutra
- Mechanical Engineering Graduate Program, Universidade do Vale do Rio dos Sinos, 93022-750, São Leopoldo, Brazil
| | - F S F Zinani
- Mechanical Engineering Graduate Program, Universidade do Vale do Rio dos Sinos, 93022-750, São Leopoldo, Brazil
| | - L A O Rocha
- Mechanical Engineering Graduate Program, Universidade do Vale do Rio dos Sinos, 93022-750, São Leopoldo, Brazil
| | - C Biserni
- Department of Industrial Engineering (DIN), School of Engineering and Architecture, Alma Mater Studiorum - University of Bologna, Viale Risorgimento 2, 40136 Bologna, Italy.
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Jonášová A, Vimmr J. On the relevance of boundary conditions and viscosity models in blood flow simulations in patient-specific aorto-coronary bypass models. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2021; 37:e3439. [PMID: 33464717 DOI: 10.1002/cnm.3439] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/08/2020] [Revised: 01/11/2021] [Accepted: 01/14/2021] [Indexed: 06/12/2023]
Abstract
Physiologically realistic results are the aim of every blood flow simulation. This is not different in aorto-coronary bypasses where the properties of the coronary circulation may significantly affect the relevance of the performed simulations. By considering three patient-specific bypass geometries, the present article focuses on two aspects of the coronary blood flow - its phasic flow pattern and its behaviour affected by blood rheology. For the phasic flow property, a multiscale modelling approach is chosen as a means to assess the ability of five different types of coronary boundary conditions (mean arterial pressure, Windkessel model and three lumped parameter models) to attain realistic coronary haemodynamics. From the analysed variants of boundary conditions, the best option in terms of physiological characteristics and its potential for use in patient-based simulations, is utilised to account for the effect of shear-dependent viscosity on the resulting haemodynamics and wall shear stress stimulation. Aside from the Newtonian model, the blood rheology is approximated by two non-Newtonian models in order to determine whether the choice of a viscosity model is important in simulations involving coronary circulation. A comprehensive analysis of obtained results demonstrated notable superiority of all lumped parameter models, especially in comparison to the constant outlet pressure, which regardless of bypass type gave overestimated and physiologically misleading results. In terms of rheology, it was noted that blood in undamaged coronary arteries behaves as a Newtonian fluid, whereas in vessels with atypical lumen geometry, such as that of anastomosis or stenosis, its shear-thinning behaviour should not be ignored.
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Affiliation(s)
- Alena Jonášová
- NTIS - New Technologies for the Information Society, Faculty of Applied Sciences, University of West Bohemia, Plzeň, Czech Republic
- Department of Mechanics, Faculty of Applied Sciences, University of West Bohemia, Plzeň, Czech Republic
| | - Jan Vimmr
- NTIS - New Technologies for the Information Society, Faculty of Applied Sciences, University of West Bohemia, Plzeň, Czech Republic
- Department of Mechanics, Faculty of Applied Sciences, University of West Bohemia, Plzeň, Czech Republic
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Alizadehghobadi S, Biglari H, Niroomand-Oscuii H, Matin MH. Numerical study of hemodynamics in a complete coronary bypass with venous and arterial grafts and different degrees of stenosis. Comput Methods Biomech Biomed Engin 2020; 24:883-896. [PMID: 33307817 DOI: 10.1080/10255842.2020.1857744] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Cardiovascular diseases are among the leading causes of death in the world. The coronary blockage is one of most common types of these diseases that in the majority of cases has been treated by bypass surgery. In the bypass surgery, a graft is implemented to alter the blocked coronary and allow the blood supply process. The hemodynamic characteristics of the bypass strongly depend on the geometry and mechanical properties of the graft. In the present study, the fluid-structure interaction (FSI) analysis is conducted to investigate the bypass performance for a thoracic artery as well as a saphenous vein graft. Blood flow introduces a pressure on the walls of the graft which behaves as a hyperelastic material. A complete coronary bypass with stenosis degrees of 70% and 100% is modeled. To consider the nonlinear stress-strain behavior of the grafts, a five parameter Mooney-Rivlin hyperplastic model is implemented for the structural analysis and blood is assumed to behave as a Newtonian fluid. The simulations are performed for a structured grid to solve the governing equations using finite element method (FEM). The results show that wall shear stress (WSS) for saphenous vein is larger than that of thoracic artery while the total deformation of the thoracic artery is larger compared to the saphenous vein. Also, for the venous grafts or lower stenosis degree, the oscillatory shear index (OSI) is higher at both left and right anastomoses meaning that venous grafts as well as lower degree of stenosis are more critical in terms of restenosis.
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Affiliation(s)
| | - Hasan Biglari
- Department of Mechanical Engineering, University of Tabriz, Tabriz, Iran
| | | | - Meisam H Matin
- Department of Mechanical and Aerospace Engineering, University of Florida, Gainesville, FL, USA
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Role of Occlusion Position in Coronary Artery Fistulas with Terminal Aneurysms: A Hemodynamic Perspective. Cardiovasc Eng Technol 2020; 11:394-404. [DOI: 10.1007/s13239-020-00468-w] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/04/2019] [Accepted: 05/16/2020] [Indexed: 12/19/2022]
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10
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Computational fluid dynamic study of multiple sequential coronary artery bypass anastomoses in a native coronary stenosis model. Coron Artery Dis 2020; 31:458-463. [PMID: 32271246 DOI: 10.1097/mca.0000000000000864] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND The objective of this study was to evaluate the hemodynamic characteristics of multiple sequential coronary artery bypass grafting using a computational fluid dynamics study. METHODS First anastomosis was configured into parallel and diamond anastomoses, and the second anastomosis was set as end-side anastomosis. The anastomosis incision lengths were fixed at 2 mm. Various combinations of the degree of first and second stenoses were studied. The diameter of both the native and graft vessels was set at 2 mm. The inlet boundary condition was set by a sample of the transient time flow measurement, which was measured intraoperatively. RESULTS Both swirl and stagnation were observed at the outlets of the stenosis and the anastomosis sites. When the severity of the second stenosis was larger than that of the first, the flow at the outlet of the second stenosis was more unstable. Higher wall shear stress and larger oscillatory shear index regions were observed when the severe stenosis was bypassed by the first anastomosis, especially with diamond anastomoses. Less energy loss and higher energy efficiency were present when the vessel with more severe stenosis was bypassed as the second anastomosis. Energy loss was lower and energy efficiency was higher with parallel anastomosis than diamond anastomosis when the severity of the two stenoses was the same. CONCLUSIONS It is ideal to bypass the less severe stenosis vessel first with a parallel anastomosis method when employing multiple sequential bypass grafting. This improves hemodynamic stability and energy efficiency, according to a computational fluid dynamics model.
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Cao H, Qiu Y, Yuan D, Yu J, Li D, Jiang Y, Su L, Peng L, Zheng T. A computational fluid dynamics study pre- and post-fistula closure in a coronary artery fistula. Comput Methods Biomech Biomed Engin 2019; 23:33-42. [PMID: 31805773 DOI: 10.1080/10255842.2019.1699540] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Affiliation(s)
- Haoyao Cao
- Department of Applied Mechanics, Sichuan University, Chengdu, China
| | - Yue Qiu
- Department of Applied Mechanics, Sichuan University, Chengdu, China
| | - Ding Yuan
- Department of Vascular Surgery, West China Hospital, Sichuan University, Chengdu, China
| | - Jianqun Yu
- Department of Radiology, West China Hospital, Sichuan University, Chengdu, China
| | - Da Li
- Department of Applied Mechanics, Sichuan University, Chengdu, China
| | - Yi Jiang
- Department of Applied Mechanics, Sichuan University, Chengdu, China
| | - Li Su
- Department of Radiology, West China Hospital, Sichuan University, Chengdu, China
| | - Liqing Peng
- Department of Radiology, West China Hospital, Sichuan University, Chengdu, China
| | - Tinghui Zheng
- Department of Applied Mechanics, Sichuan University, Chengdu, China
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Matsuura K, Jin WW, Liu H, Matsumiya G. Computational fluid dynamic study of different incision length of coronary artery bypass grafting in a native coronary stenosis model. J Thorac Dis 2019; 11:393-399. [PMID: 30962982 DOI: 10.21037/jtd.2019.01.35] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Background The objective of this study was to evaluate hemodynamic patterns in end-side coronary artery bypass grafting with different anastomosis length by computational fluid dynamic study in the native coronary stenosis model. Methods The fluid dynamic computations were carried out using ANSYS CFX. Incision length was set to be 2, 4, 6, 8, 10 mm. The angle between the two blood vessels corresponded to the length of the incision. Native vessels were set to be 90% stenosis. The radius of both native and graft vessels was set to be 2 mm. The inlet boundary condition was set by the sample of the transient time flow which was measured intraoperatively. Results The energy efficiency was higher and energy loss was lower when the anastomosis length was longer until 8 mm. However, energy efficiency was lowest and energy loss was highest in the 10-mm model. In the 10-mm incision model, the streamline showed the scanty bypass flow in the bottom. Vortex showed that only 10-mm model showed the vortex just distal to the stenosis in the native inlet, and more vortex in native outlet than other length models. The oscillatory shear index (OSI) was higher in the outlet top in all models. And only 10-mm model showed high oscillatory index just distal to the stenosis. Conclusions In the end-side anastomosis, an anastomosis length of 8 mm was the ideal length with less flow complexity, low OSI, and less energy loss and high energy efficiency in the native 90% stenosis model.
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Affiliation(s)
- Kaoru Matsuura
- Department of Cardiovascular Surgery, Chiba University Hospital, Chiba, Japan
| | - Wei Wei Jin
- Graduate School of Engineering, Chiba University, Chiba, Japan.,Department of Biomedical Engineering, School of Biomedical Engineering & Imaging Sciences, Faculty of Life Science and Medicine, King's College London, London, UK
| | - Hao Liu
- Graduate School of Engineering, Chiba University, Chiba, Japan
| | - Goro Matsumiya
- Department of Cardiovascular Surgery, Chiba University Hospital, Chiba, Japan
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The effect of plaque eccentricity on blood hemodynamics and drug release in a stented artery. Med Eng Phys 2018; 60:47-60. [DOI: 10.1016/j.medengphy.2018.07.014] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2017] [Revised: 07/20/2018] [Accepted: 07/24/2018] [Indexed: 11/17/2022]
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14
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Permeability and fluid flow-induced wall shear stress of bone tissue scaffolds: Computational fluid dynamic analysis using Newtonian and non-Newtonian blood flow models. Comput Biol Med 2018; 99:201-208. [DOI: 10.1016/j.compbiomed.2018.06.017] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2018] [Revised: 06/02/2018] [Accepted: 06/18/2018] [Indexed: 12/17/2022]
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Guerciotti B, Vergara C. Computational Comparison Between Newtonian and Non-Newtonian Blood Rheologies in Stenotic Vessels. BIOMEDICAL TECHNOLOGY 2018. [DOI: 10.1007/978-3-319-59548-1_10] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
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16
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Computational fluid dynamics study of the end-side and sequential coronary artery bypass anastomoses in a native coronary occlusion model†. Interact Cardiovasc Thorac Surg 2017; 26:583-589. [DOI: 10.1093/icvts/ivx376] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2017] [Accepted: 10/27/2017] [Indexed: 11/14/2022] Open
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Guerciotti B, Vergara C, Ippolito S, Quarteroni A, Antona C, Scrofani R. A computational fluid–structure interaction analysis of coronary Y-grafts. Med Eng Phys 2017; 47:117-127. [DOI: 10.1016/j.medengphy.2017.05.008] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2017] [Revised: 04/12/2017] [Accepted: 05/16/2017] [Indexed: 10/19/2022]
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Al-Azawy MG, Turan A, Revell A. Investigating the impact of non-Newtonian blood models within a heart pump. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2017; 33. [PMID: 26919069 DOI: 10.1002/cnm.2780] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2015] [Revised: 02/08/2016] [Accepted: 02/21/2016] [Indexed: 05/08/2023]
Abstract
A detailed computational fluid dynamics (CFD) study of transient, turbulent blood flow through a positive displacement left ventricular assist device is performed. Two common models for non-Newtonian blood flow are compared to the Newtonian model to investigate their impact on predicted levels of shear rate and wall shear stress. Given that both parameters are directly relevant to the evaluation of risk from thrombus and haemolysis, there is a need to assess the sensitivity to modelling non-Newtonian flow effects within a pulsatile turbulent flow, in order to identify levels of uncertainly in CFD. To capture the effects of turbulence, the elliptic blending Reynolds stress model is used in the present study, on account of superior performance of second moment closure schemes previously identified by the present authors. The CFD configuration includes two cyclically rotating valves and a moving pusher plate to periodically vary the chamber volume. An overset mesh algorithm is used for each instance of mesh motion, and a zero gap technique was employed to ensure full valve closure. The left ventricular assist device was operated at a pumping rate of 86 BPM (beats per minute) and a systolic duration of 40% of the pumping cycle, in line with existing experimental data to which comparisons are made. The sensitivity of the variable viscosity models is investigated in terms of mean flow field, levels of turbulence and global shear rate, and a non-dimensional index is used to directly evaluate the impact of non-Newtonian effects. The clinical relevance of the results is reported along with a discussion of modelling uncertainties, observing that the turbulent kinetic energy is generally predicted to be higher in non-Newtonian flow than that observed in Newtonian flow. Copyright © 2016 John Wiley & Sons, Ltd.
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Affiliation(s)
- Mohammed G Al-Azawy
- School of Mechanical, Aerospace and Civil Engineering, The University of Manchester
- Mechanical Engineering Department, College of Engineering, Wasit University, Wasit, Iraq
| | - A Turan
- School of Mechanical, Aerospace and Civil Engineering, The University of Manchester
| | - A Revell
- School of Mechanical, Aerospace and Civil Engineering, The University of Manchester
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Computational study of the risk of restenosis in coronary bypasses. Biomech Model Mechanobiol 2016; 16:313-332. [DOI: 10.1007/s10237-016-0818-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2016] [Accepted: 08/09/2016] [Indexed: 10/21/2022]
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Doost SN, Zhong L, Su B, Morsi YS. The numerical analysis of non-Newtonian blood flow in human patient-specific left ventricle. COMPUTER METHODS AND PROGRAMS IN BIOMEDICINE 2016; 127:232-247. [PMID: 26849955 DOI: 10.1016/j.cmpb.2015.12.020] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2015] [Accepted: 12/21/2015] [Indexed: 06/05/2023]
Abstract
Recently, various non-invasive tools such as the magnetic resonance image (MRI), ultrasound imaging (USI), computed tomography (CT), and the computational fluid dynamics (CFD) have been widely utilized to enhance our current understanding of the physiological parameters that affect the initiation and the progression of the cardiovascular diseases (CVDs) associated with heart failure (HF). In particular, the hemodynamics of left ventricle (LV) has attracted the attention of the researchers due to its significant role in the heart functionality. In this study, CFD owing its capability of predicting detailed flow field was adopted to model the blood flow in images-based patient-specific LV over cardiac cycle. In most published studies, the blood is modeled as Newtonian that is not entirely accurate as the blood viscosity varies with the shear rate in non-linear manner. In this paper, we studied the effect of Newtonian assumption on the degree of accuracy of intraventricular hemodynamics. In doing so, various non-Newtonian models and Newtonian model are used in the analysis of the intraventricular flow and the viscosity of the blood. Initially, we used the cardiac MRI images to reconstruct the time-resolved geometry of the patient-specific LV. After the unstructured mesh generation, the simulations were conducted in the CFD commercial solver FLUENT to analyze the intraventricular hemodynamic parameters. The findings indicate that the Newtonian assumption cannot adequately simulate the flow dynamic within the LV over the cardiac cycle, which can be attributed to the pulsatile and recirculation nature of the flow and the low blood shear rate.
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Affiliation(s)
- Siamak N Doost
- Biomechanical and Tissue Engineering Lab, Faculty of Science, Engineering and Technology, Swinburne University of Technology, Australia.
| | - Liang Zhong
- Duke-NUS Graduate Medical School, Singapore; National Heart Research Institute of Singapore, National Heart Centre, Singapore.
| | - Boyang Su
- National Heart Research Institute of Singapore, National Heart Centre, Singapore
| | - Yosry S Morsi
- Biomechanical and Tissue Engineering Lab, Faculty of Science, Engineering and Technology, Swinburne University of Technology, Australia
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Franz T. Computational mechanics and electro-mechanics in cardiovascular physiology and disease. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2014; 30:603-604. [PMID: 24285640 DOI: 10.1002/cnm.2617] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Affiliation(s)
- Thomas Franz
- Cardiovascular Research Unit, Chris Barnard Division of Cardiothoracic Surgery, University of Cape Town, Observatory, South Africa; Research Office, University of Cape Town, Mowbray, South Africa; Centre for Research in Computational and Applied Mechanics, University of Cape Town, Rondebosch, South Africa
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