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Kjeldsberg HA, Albors C, Mill J, Medel DV, Camara O, Sundnes J, Valen-Sendstad K. Impact of left atrial wall motion assumptions in fluid simulations on proposed predictors of thrombus formation. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2024; 40:e3825. [PMID: 38629309 DOI: 10.1002/cnm.3825] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2023] [Revised: 02/18/2024] [Accepted: 04/05/2024] [Indexed: 06/11/2024]
Abstract
Atrial fibrillation (AF) poses a significant risk of stroke due to thrombus formation, which primarily occurs in the left atrial appendage (LAA). Medical image-based computational fluid dynamics (CFD) simulations can provide valuable insight into patient-specific hemodynamics and could potentially enhance personalized assessment of thrombus risk. However, the importance of accurately representing the left atrial (LA) wall dynamics has not been fully resolved. In this study, we compared four modeling scenarios; rigid walls, a generic wall motion based on a reference motion, a semi-generic wall motion based on patient-specific motion, and patient-specific wall motion based on medical images. We considered a LA geometry acquired from 4D computed tomography during AF, systematically performed convergence tests to assess the numerical accuracy of our solution strategy, and quantified the differences between the four approaches. The results revealed that wall motion had no discernible impact on LA cavity hemodynamics, nor on the markers that indicate thrombus formation. However, the flow patterns within the LAA deviated significantly in the rigid model, indicating that the assumption of rigid walls may lead to errors in the estimated risk factors. In contrast, the generic, semi-generic, and patient-specific cases were qualitatively similar. The results highlight the crucial role of wall motion on hemodynamics and predictors of thrombus formation, and also demonstrate the potential of using a generic motion model as a surrogate for the more complex patient-specific motion. While the present study considered a single case, the employed CFD framework is entirely open-source and designed for adaptability, allowing for integration of additional models and generic motions.
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Affiliation(s)
- Henrik A Kjeldsberg
- Department of Computational Physiology, Simula Research Laboratory, Oslo, Norway
| | - Carlos Albors
- Department of Information and Communication Technologies, Universitat Pompeu Fabra, Barcelona, Spain
| | - Jordi Mill
- Department of Information and Communication Technologies, Universitat Pompeu Fabra, Barcelona, Spain
| | | | - Oscar Camara
- Department of Information and Communication Technologies, Universitat Pompeu Fabra, Barcelona, Spain
| | - Joakim Sundnes
- Department of Computational Physiology, Simula Research Laboratory, Oslo, Norway
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2
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Richter K, Probst T, Hundertmark A, Eulzer P, Lawonn K. Longitudinal wall shear stress evaluation using centerline projection approach in the numerical simulations of the patient-based carotid artery. Comput Methods Biomech Biomed Engin 2024; 27:347-364. [PMID: 36880851 DOI: 10.1080/10255842.2023.2185478] [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] [Received: 10/07/2022] [Revised: 02/07/2023] [Accepted: 02/17/2023] [Indexed: 03/08/2023]
Abstract
In this numerical study, areas of the carotid bifurcation and of a distal stenosis in the internal carotid artery are closely observed to evaluate the patient's current risks of ischemic stroke. An indicator for the vessel wall defects is the stress exerted by blood on the vessel tissue, typically expressed by the amplitude of the wall shear stress vector (WSS) and its oscillatory shear index. To detect negative shear stresses corresponding with reversal flow, we perform orientation-based shear evaluation. We investigate the longitudinal component of the wall shear vector, where tangential vectors aligned longitudinally with the vessel are necessary. However, resulting from imaging segmentation resolution of patients' computed tomography angiography scans and stenotic regions, the geometry model's mesh is non-smooth on its surface areas and the automatically generated tangential vector field is discontinuous and multi-directional, making an interpretation of our orientation-based risk indicators unreliable. We improve the evaluation of longitudinal shear stress by applying the projection of the vessel's centerline to the surface to construct smooth tangential field aligned longitudinally with the vessel. We validate our approach for the longitudinal WSS component and the corresponding oscillatory index by comparing them to results obtained using automatically generated tangents in both rigid and elastic vessel modeling and to amplitude-based indicators. We present the major benefit of our longitudinal WSS evaluation based on its directionality for the cardiovascular risk assessment, which is the detection of negative WSS indicating persistent reversal or transverse flow. This is impossible in the case of the amplitude-based WSS.
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Affiliation(s)
- Kevin Richter
- Institute of Mathematics, Faculty of Natural and Environmental Sciences, University of Kaiserslautern-Landau, Germany
| | - Tristan Probst
- Institute of Mathematics, Faculty of Natural and Environmental Sciences, University of Kaiserslautern-Landau, Germany
| | - Anna Hundertmark
- Institute of Mathematics, Faculty of Natural and Environmental Sciences, University of Kaiserslautern-Landau, Germany
| | - Pepe Eulzer
- Faculty of Mathematics and Computer Science, University of Jena, Germany
| | - Kai Lawonn
- Faculty of Mathematics and Computer Science, University of Jena, Germany
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3
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Wang T, Yong Y, Ge X, Wang J. A computational model-based study on the feasibility of predicting post-splenectomy thrombosis using hemodynamic metrics. Front Bioeng Biotechnol 2024; 11:1276999. [PMID: 38274008 PMCID: PMC10808826 DOI: 10.3389/fbioe.2023.1276999] [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: 08/13/2023] [Accepted: 10/30/2023] [Indexed: 01/27/2024] Open
Abstract
For portal hypertensive patients with splenomegaly and hypersplenism, splenectomy is an effective surgery to relieve the complications. However, patients who have undergone splenectomy often suffer from portal venous system thrombosis, a sequela that requires prophylaxis and timely treatment to avoid deterioration and death. The aim of this study is to investigate the feasibility of predicting post-splenectomy thrombosis using hemodynamic metrics based on computational models. First, 15 portal hypertensive patients who had undergone splenectomy were enrolled, and their preoperative clinical data and postoperative follow-up results were collected. Next, computational models of the portal venous system were constructed based on the preoperative computed tomography angiography images and ultrasound-measured flow velocities. On this basis, splenectomy was mimicked and the postoperative area of low wall shear stress (ALWSS) was simulated for each patient-specific model. Finally, model-simulated ALWSS was statistically compared with the patient follow-up results to investigate the feasibility of predicting post-splenectomy thrombosis using hemodynamic metrics. Results showed that ALWSS could predict the occurrence of post-splenectomy thrombosis with the area under the receiver operating characteristic curve (AUC) equal to 0.75. Moreover, statistical analysis implied that the diameter of the splenic vein is positively correlated with ALWSS (r = 0.883, p < 0.0001), and the anatomical structures of the portal venous system also influence the ALWSS. These findings demonstrated that the computational model-based hemodynamic metric ALWSS, which is associated with the anatomorphological features of the portal venous system, is capable of predicting the occurrence of post-splenectomy thrombosis, promoting better prophylaxis and postoperative management for portal hypertensive patients receiving splenectomy.
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Affiliation(s)
- Tianqi Wang
- School of Gongli Hospital Medical Technology, University of Shanghai for Science and Technology, Shanghai, China
- School of Mechanical Engineering, University of Shanghai for Science and Technology, Shanghai, China
| | - Yan Yong
- College of Science, University of Shanghai for Science and Technology, Shanghai, China
| | - Xinyang Ge
- College of Mathematical Medicine, Zhejiang Normal University, Jinhua, China
| | - Jitao Wang
- Department of Hepatobiliary Surgery, Xingtai Institute of Cancer Control, Xingtai, China
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Brüning J, Yevtushenko P, Schlief A, Jochum T, van Gijzen L, Meine S, Romberg J, Kuehne T, Arndt A, Goubergrits L. In-silico enhanced animal study of pulmonary artery pressure sensors: assessing hemodynamics using computational fluid dynamics. Front Cardiovasc Med 2023; 10:1193209. [PMID: 37745132 PMCID: PMC10517052 DOI: 10.3389/fcvm.2023.1193209] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2023] [Accepted: 08/17/2023] [Indexed: 09/26/2023] Open
Abstract
To assess whether in-silico models can be used to predict the risk of thrombus formation in pulmonary artery pressure sensors (PAPS), a chronic animal study using pigs was conducted. Computed tomography (CT) data was acquired before and immediately after implantation, as well as one and three months after the implantation. Devices were implanted into 10 pigs, each one in the left and right pulmonary artery (PA), to reduce the required number of animal experiments. The implantation procedure aimed at facilitating optimal and non-optimal positioning of the devices to increase chances of thrombus formation. Eight devices were positioned non-optimally. Three devices were positioned in the main PA instead of the left and right PA. Pre-interventional PA geometries were reconstructed from the respective CT images, and the devices were virtually implanted at the exact sites and orientations indicated by the follow-up CT after one month. Transient intra-arterial hemodynamics were calculated using computational fluid dynamics. Volume flow rates were modelled specifically matching the animals body weights. Wall shear stresses (WSS) and oscillatory shear indices (OSI) before and after device implantation were compared. Simulations revealed no relevant changes in any investigated hemodynamic parameters due to device implantation. Even in cases, where devices were implanted in a non-optimal manner, no marked differences in hemodynamic parameters compared to devices implanted in an optimal position were found. Before implantation time and surface-averaged WSS was 2.35 ± 0.47 Pa, whereas OSI was 0.08 ± 0.17 , respectively. Areas affected by low WSS magnitudes were 2.5 ± 2.7 cm2 , whereas the areas affected by high OSI were 18.1 ± 6.3 cm2 . After device implantation, WSS and OSI were 2.45 ± 0.49 Pa and 0.08 ± 0.16 , respectively. Surface areas affected by low WSS and high OSI were 2.9 ± 2.7 cm2 , and 18.4 ± 6.1 cm2 , respectively. This in-silico study indicates that no clinically relevant differences in intra-arterial hemodynamics are occurring after device implantation, even at non-optimal positioning of the sensor. Simultaneously, no embolic events were observed, suggesting that the risk for thrombus formation after device implantation is low and independent of the sensor position.
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Affiliation(s)
- Jan Brüning
- Institute of Computer-assisted Cardiovascular Medicine, Deutsches Herzzentrum der Charité, Berlin, Germany
- Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Pavlo Yevtushenko
- Institute of Computer-assisted Cardiovascular Medicine, Deutsches Herzzentrum der Charité, Berlin, Germany
- Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Adriano Schlief
- Institute of Computer-assisted Cardiovascular Medicine, Deutsches Herzzentrum der Charité, Berlin, Germany
- Charité - Universitätsmedizin Berlin, Berlin, Germany
| | | | | | | | | | - Titus Kuehne
- Institute of Computer-assisted Cardiovascular Medicine, Deutsches Herzzentrum der Charité, Berlin, Germany
- Charité - Universitätsmedizin Berlin, Berlin, Germany
| | | | - Leonid Goubergrits
- Institute of Computer-assisted Cardiovascular Medicine, Deutsches Herzzentrum der Charité, Berlin, Germany
- Charité - Universitätsmedizin Berlin, Berlin, Germany
- Einstein Center Digital Future, Berlin, Germany
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Liu Q, Sarrami-Foroushani A, Wang Y, MacRaild M, Kelly C, Lin F, Xia Y, Song S, Ravikumar N, Patankar T, Taylor ZA, Lassila T, Frangi AF. Hemodynamics of thrombus formation in intracranial aneurysms: An in silico observational study. APL Bioeng 2023; 7:036102. [PMID: 37426382 PMCID: PMC10329514 DOI: 10.1063/5.0144848] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2023] [Accepted: 06/07/2023] [Indexed: 07/11/2023] Open
Abstract
How prevalent is spontaneous thrombosis in a population containing all sizes of intracranial aneurysms? How can we calibrate computational models of thrombosis based on published data? How does spontaneous thrombosis differ in normo- and hypertensive subjects? We address the first question through a thorough analysis of published datasets that provide spontaneous thrombosis rates across different aneurysm characteristics. This analysis provides data for a subgroup of the general population of aneurysms, namely, those of large and giant size (>10 mm). Based on these observed spontaneous thrombosis rates, our computational modeling platform enables the first in silico observational study of spontaneous thrombosis prevalence across a broader set of aneurysm phenotypes. We generate 109 virtual patients and use a novel approach to calibrate two trigger thresholds: residence time and shear rate, thus addressing the second question. We then address the third question by utilizing this calibrated model to provide new insight into the effects of hypertension on spontaneous thrombosis. We demonstrate how a mechanistic thrombosis model calibrated on an intracranial aneurysm cohort can help estimate spontaneous thrombosis prevalence in a broader aneurysm population. This study is enabled through a fully automatic multi-scale modeling pipeline. We use the clinical spontaneous thrombosis data as an indirect population-level validation of a complex computational modeling framework. Furthermore, our framework allows exploration of the influence of hypertension in spontaneous thrombosis. This lays the foundation for in silico clinical trials of cerebrovascular devices in high-risk populations, e.g., assessing the performance of flow diverters in aneurysms for hypertensive patients.
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Affiliation(s)
| | | | | | | | - Christopher Kelly
- Centre for Computational Imaging and Simulation Technologies in Biomedicine (CISTIB), School of Computing, University of Leeds, Leeds, United Kingdom
| | | | | | | | - Nishant Ravikumar
- Centre for Computational Imaging and Simulation Technologies in Biomedicine (CISTIB), School of Computing, University of Leeds, Leeds, United Kingdom
| | | | - Zeike A. Taylor
- School of Mechanical Engineering, University of Leeds, Leeds, United Kingdom
| | - Toni Lassila
- Centre for Computational Imaging and Simulation Technologies in Biomedicine (CISTIB), School of Computing, University of Leeds, Leeds, United Kingdom
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Predicting the risk of postsplenectomy thrombosis in patients with portal hypertension using computational hemodynamics models: A proof-of-concept study. Clin Biomech (Bristol, Avon) 2022; 98:105717. [PMID: 35834965 DOI: 10.1016/j.clinbiomech.2022.105717] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/10/2021] [Revised: 06/05/2022] [Accepted: 07/06/2022] [Indexed: 02/07/2023]
Abstract
BACKGROUND The high incidence of thrombosis in the portal venous system following splenectomy (a frequently adopted surgery for treating portal hypertension in patients with splenomegaly and hypersplenism) is a critical clinical issue. The aim of this study was to address whether quantification of postsplenectomy hemodynamics has potential value for assessing the risk of postsplenectomy thrombosis. METHODS Computational models were constructed for three portal hypertensive patients treated with splenectomy based on their preoperative clinical data to quantify hemodynamics in the portal venous system before and after splenectomy, respectively. Each patient was followed up for three or five months after surgery and examined with CT to screen potential thrombosis. FINDINGS The area ratio of wall regions exposed to low wall shear stress was small before splenectomy in all patients, which increased markedly after splenectomy and exhibited enlarged inter-patient differences. The largest area ratio of low wall shear stress and most severe flow stagnation after splenectomy were predicted for the patient suffering from postsplenectomy thrombosis, with the wall regions exposed to low wall shear stress corresponding well with the CT-detected distribution of thrombus. Further analyses revealed that postoperative hemodynamic characteristics were considerably influenced by the anatomorphological features of the portal venous system. INTERPRETATION Postoperative hemodynamic conditions in the portal venous system are highly patient-specific and have a potential link to postsplenectomy thrombosis, which indicates that patient-specific hemodynamic studies may serve as a complement to routine clinical assessments for refining risk stratification and postoperative patient management.
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Dueñas-Pamplona J, García JG, Sierra-Pallares J, Ferrera C, Agujetas R, López-Mínguez JR. A comprehensive comparison of various patient-specific CFD models of the left atrium for atrial fibrillation patients. Comput Biol Med 2021; 133:104423. [PMID: 33957460 DOI: 10.1016/j.compbiomed.2021.104423] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2021] [Revised: 04/13/2021] [Accepted: 04/17/2021] [Indexed: 11/30/2022]
Abstract
BACKGROUND Recently, advances in medical imaging, segmentation techniques, and high-performance computing have supported the use of patient-specific computational fluid dynamics (CFD) simulations. At present, CFD-compatible atrium geometries can be easily reconstructed from atrium images, providing important insight into the atrial fibrillation (AF) phenomenon, and assistance during therapy selection and surgical procedures. However, the hypothesis assumed for such CFD models should be adequately validated. AIM This work aims to perform an extensive study of the different hypotheses that are commonly assumed when performing atrial simulations for AF patients, as well as to evaluate and compare the range of indices that are usually applied to assess thrombus formation within the left atrium appendage (LAA). METHODS The atrial geometries of two AF patients have been segmented. The resulting geometries have been registered and interpolated to construct a dynamic mesh, which has been employed to compare the rigid and flexible models. Two families of hemodynamic indices have been calculated and compared: wall shear-based and blood age distribution-based. RESULTS The findings of this study illustrate the importance of validating the rigid atrium hypothesis when utilizing an AF CFD model. In particular, the absence of the A-wave contraction does not avoid a certain degree of passive atrial contraction, making the rigid model a poor approximation in some cases. Moreover, a new thrombosis predicting index has been proposed, i.e., M4, which has been shown to predict stasis more effectively than other indicators.
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Affiliation(s)
- Jorge Dueñas-Pamplona
- Departamento de Ingeniería Energética, Escuela Técnica Superior de Ingenieros Industriales, Universidad Politécnica de Madrid, C/ José Gutiérrez Abascal 2, Madrid, Spain.
| | - Javier García García
- Departamento de Ingeniería Energética, Escuela Técnica Superior de Ingenieros Industriales, Universidad Politécnica de Madrid, C/ José Gutiérrez Abascal 2, Madrid, Spain
| | - José Sierra-Pallares
- Departamento de Ingeniería Energética y Fluidomecánica, Escuela de Ingenieros Industriales, Universidad de Valladolid, C/ Paseo Del Cauce 59, Valladolid, Spain
| | - Conrado Ferrera
- Departamento de Ingeniería Mecánica, Energética y de Los Materiales, Escuela de Ingenierías Industriales and Instituto de Computación Científica Avanzada (ICCAEX). Universidad de Extremadura, Avda.de Elvas S/n, 06006, Badajoz, Spain
| | - Rafael Agujetas
- Departamento de Ingeniería Mecánica, Energética y de Los Materiales, Escuela de Ingenierías Industriales and Instituto de Computación Científica Avanzada (ICCAEX). Universidad de Extremadura, Avda.de Elvas S/n, 06006, Badajoz, Spain
| | - José Ramón López-Mínguez
- Sección de Cardiología Intervencionista, Servicio de Cardiología, Hospital Universitario de Badajoz, Avda. de Elvas S/n, 06006, Badajoz, Spain
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Wang T, Zhou Z, Liang F. Influences of Anatomorphological Features of the Portal Venous System on Postsplenectomy Hemodynamic Characteristics in Patients With Portal Hypertension: A Computational Model-Based Study. Front Physiol 2021; 12:661030. [PMID: 33912074 PMCID: PMC8072460 DOI: 10.3389/fphys.2021.661030] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2021] [Accepted: 03/22/2021] [Indexed: 11/13/2022] Open
Abstract
Splenectomy, as an effective surgery for relieving complications caused by portal hypertension, is often accompanied by a significantly increased incidence of postoperative thrombosis in the portal venous system (PVS). While the underlying mechanisms remain insufficiently understood, the marked changes in hemodynamic conditions in the PVS following splenectomy have been suggested to be a potential contributing factor. The aim of this study was to investigate the influences of the anatomorphological features of the PVS on hemodynamic characteristics before and after splenectomy, with emphasis on identifying the specific anatomorphological features that make postoperative hemodynamic conditions more clot-promoting. For this purpose, idealized computational hemodynamics models of the PVS were constructed based on general anatomical structures and population-averaged geometrical parameters of the PVS. In the models, we incorporated various anatomorphological variations to represent inter-patient variability. The analyses of hemodynamic data were focused on the spatial distribution of wall shear stress (WSS) and the area ratio of wall regions exposed to low WSS (ALS). Obtained results showed that preoperative hemodynamic conditions were comparable among different models in terms of space-averaged WSS and ALS (all were small) irrespective of the considerable differences in spatial distribution of WSS, whereas, the inter-model differences in ALS were significantly augmented after splenectomy, with the value of ALS reaching up to over 30% in some models, while being smaller than 15% in some other models. Postoperative ALS was mainly determined by the anatomical structure of the PVS, followed by some morphogeometrical parameters, such as the diameter and curvature of the splenic vein, and the distance between the inferior mesenteric vein and splenoportal junction. Relatively, the angles between tributary veins and trunk veins only had mild influences on ALS. In addition, a marked increase in blood viscosity was predicted after splenectomy, especially in regions with low WSS, which may play an additive role to low WSS in initiating thrombosis. These findings suggest that the anatomical structure and some morphogeometrical features of the PVS are important determinants of hemodynamic conditions following splenectomy, which may provide useful clues to assessing the risk of postsplenectomy thrombosis based on medical imaging data.
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Affiliation(s)
- Tianqi Wang
- State Key Laboratory of Ocean Engineering, School of Naval Architecture, Ocean and Civil Engineering, Shanghai Jiao Tong University, Shanghai, China
| | - Zunqiang Zhou
- Department of Surgery, Shanghai Jiao Tong University Affiliated Sixth People’s Hospital, Shanghai, China
| | - Fuyou Liang
- State Key Laboratory of Ocean Engineering, School of Naval Architecture, Ocean and Civil Engineering, Shanghai Jiao Tong University, Shanghai, China
- Key Laboratory of Hydrodynamics (Ministry of Education), School of Naval Architecture, Ocean and Civil Engineering, Shanghai Jiao Tong University, Shanghai, China
- World-Class Research Center “Digital Biodesign and Personalized Healthcare,” Sechenov First Moscow State Medical University, Moscow, Russia
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Colley E, Simmons A, Varcoe R, Thomas S, Barber T. Arteriovenous fistula maturation and the influence of fluid dynamics. Proc Inst Mech Eng H 2020; 234:1197-1208. [DOI: 10.1177/0954411920926077] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Arteriovenous fistula creation is the preferred vascular access for haemodialysis therapy, but has a large failure rate in the maturation period. This period generally lasts 6 to 8 weeks after surgical creation, in which the vein and artery undergo extensive vascular remodelling. In this review, we outline proposed mechanisms for both arteriovenous fistula maturation and arteriovenous fistula failure. Clinical, animal and computational studies have not yet shown a definitive link between any metric and disease development, although a number of theories based on wall shear stress metrics have been suggested. Recent work allowing patient-based longitudinal studies may hold the key to understanding arteriovenous fistula maturation processes.
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Affiliation(s)
- Eamonn Colley
- School of Mechanical Engineering, University of New South Wales, Sydney, NSW, Australia
| | - Anne Simmons
- School of Mechanical Engineering, University of New South Wales, Sydney, NSW, Australia
| | - Ramon Varcoe
- Prince of Wales Hospital, Sydney, NSW, Australia
| | | | - Tracie Barber
- School of Mechanical Engineering, University of New South Wales, Sydney, NSW, Australia
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Javadzadegan A, Moshfegh A, Mohammadi M, Askarian M, Mohammadi M. Haemodynamic impacts of myocardial bridge length: A congenital heart disease. COMPUTER METHODS AND PROGRAMS IN BIOMEDICINE 2019; 175:25-33. [PMID: 31104712 DOI: 10.1016/j.cmpb.2019.03.017] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/14/2018] [Revised: 02/09/2019] [Accepted: 03/27/2019] [Indexed: 06/09/2023]
Abstract
OBJECTIVES There is an association between long and thick myocardial bridging (MB), haemodynamic perturbations and increased risk of myocardial infarction. This study aims to investigate the alteration in coronary haemodynamics with increasing the length of MB. METHODS Angiography and intravascular ultrasound were performed in 10 patients with varying length of MB in the left anterior descending (LAD) artery. In silico models of MB were developed based on the reconstructed three-dimensional model of the LAD. The entire LAD was divided into 3 segments, proximal (pre-bridge), bridge and distal (post-bridge). Transient computational fluid dynamics simulations were performed to derive distribution of blood residence time and wall shear stress (WSS) over entire vessel including proximal, bridge and distal segments. RESULTS With increasing the length of MB, a decreasing trend was observed in the WSS over proximal segment whereas an increasing trend was found in the WSS over bridge segment. When patients were divided into 2 groups based on the average length of MB in the whole cohort (Lave = 23.92 mm), patients with bridges longer than Lave had smaller WSS and higher residence time in the proximal segment compared to those with bridges shorter than Lave (0.59 ± 0.31 vs 0.21 ± 0.14 Pa and 0.0021 ± 0.0015 vs 0.0045 ± 0.0021 s). In contrast, patients with bridges longer than Lave had greater WSS in the bridge segment compared to those with bridges shorter than Lave (1.37 ± 1.66 vs 2.53 ± 3.14 Pa). No significant difference was found in the distal WSS of patients with short and long bridges. CONCLUSION Our findings revealed a direct relationship between the length of MB and haemodynamic perturbations in the proximal segment such that the increased length of MB is associated with decreased WSS and increased residence time.
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Affiliation(s)
- Ashkan Javadzadegan
- Faculty of Medicine and Health Sciences, Macquarie University, Sydney, NSW 2109, Australia; ANZAC Research Institute, The University of Sydney, Sydney, NSW 2139, Australia
| | - Abouzar Moshfegh
- Faculty of Medicine and Health Sciences, Macquarie University, Sydney, NSW 2109, Australia; ANZAC Research Institute, The University of Sydney, Sydney, NSW 2139, Australia.
| | - Maryam Mohammadi
- Faculty of Medicine and Health Sciences, Macquarie University, Sydney, NSW 2109, Australia
| | - Mahsa Askarian
- Department of Community Health, School of Nursing and Midwifery, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Mahsa Mohammadi
- Department of Medicinal Chemistry, Pharmaceutical Sciences Research Center, Pharmaceutical Sciences Branch, Azad University, Tehran, Iran
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Xiong J, Hu Z, Zhang H, Xu H, Chen D, Guo W. Successful use of retrograde branched extension limb assembling technique in endovascular repair of pararenal abdominal aortic aneurysm. JOURNAL OF VASCULAR SURGERY CASES INNOVATIONS AND TECHNIQUES 2018; 3:90-94. [PMID: 29349386 PMCID: PMC5757770 DOI: 10.1016/j.jvscit.2017.02.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/28/2016] [Accepted: 02/23/2017] [Indexed: 12/03/2022]
Abstract
Surgeon-modified retrograde branched extension limb assembling technique and bridged endografts were successfully used to exclude an asymptomatic pararenal abdominal aortic aneurysm and to reconstruct the superior mesenteric artery and bilateral renal arteries in a case with high-grade celiac artery stenosis, nondilated aorta above the superior mesenteric artery, and large lumen below the renal arteries. In patient-specific models for hemodynamics analysis, enhanced flow diversion to visceral arteries up to 6-month follow-up confirmed treatment feasibility; however, endograft configurations could be improved to avoid sharp corners at bifurcations, thereby ensuring smooth flow transport and possibly reducing risk for endograft narrowing or the development of thrombosis.
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Affiliation(s)
- Jiang Xiong
- Department of Vascular and Endovascular Surgery, Chinese PLA General Hospital, Beijing, China
| | - Zhongzhou Hu
- Department of Vascular and Endovascular Surgery, Chinese PLA General Hospital, Beijing, China
| | - Hongpeng Zhang
- Department of Vascular and Endovascular Surgery, Chinese PLA General Hospital, Beijing, China
| | - Huanming Xu
- School of Life Science, Beijing Institute of Technology, Beijing, China
| | - Duanduan Chen
- School of Life Science, Beijing Institute of Technology, Beijing, China
| | - Wei Guo
- Department of Vascular and Endovascular Surgery, Chinese PLA General Hospital, Beijing, China
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Xu H, Li Z, Dong H, Zhang Y, Wei J, Watton PN, Guo W, Chen D, Xiong J. Hemodynamic parameters that may predict false-lumen growth in type-B aortic dissection after endovascular repair: A preliminary study on long-term multiple follow-ups. Med Eng Phys 2017; 50:12-21. [PMID: 28890304 DOI: 10.1016/j.medengphy.2017.08.011] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2016] [Revised: 08/03/2017] [Accepted: 08/21/2017] [Indexed: 01/16/2023]
Abstract
Thoracic endovascular aortic repair (TEVAR) is commonly applied in type-B aortic dissection. For patients with dissection affects descending aorta and extends downward to involve abdominal aorta and possibly iliac arteries, false lumen (FL) expansion might occur post-TEVAR. Predictions of dissection development may assist in medical decision on re-intervention or surgery. In this study, two patients are selected with similar morphological features at initial presentation but with different long-term FL development post-TEVAR (stable and enlarged FL). Patient-specific models are established for each of the follow-ups. Flow boundaries and computational validations are obtained from Doppler ultrasound velocimetry. By analyzing the hemodynamic parameters, the false-to-true luminal pressure difference (PDiff) and particle relative residence time (RRT) are found related to FL remodeling. It is found that (i) the position of the first FL flow entry is the watershed of negative-and-positive PDiff and, in long-term follow-ups, and the position of largest PDiff is consistent with that of the greatest increase of FL width; (ii) high RRT occurs at the FL proximal tip and similar magnitude of RRT is found in both stable and enlarged cases; (iii) comparing to the RRT at 7days post-TEVAR, an increase of RRT afterwards in short-term is found in the stable case while a slight decrease of this parameter is found in the enlarged case, indicating that the variation of RRT in short-term post-TEVAR might be potential to predict long-term FL remodeling.
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Affiliation(s)
- Huanming Xu
- School of Life Science, Beijing Institute of Technology, Beijing, 100081, China; Key Laboratory of Convergence Medical Engineering System and Healthcare Technology, The Ministry of Industry and Information Technology, Beijing Institute of Technology, China
| | - Zhenfeng Li
- School of Life Science, Beijing Institute of Technology, Beijing, 100081, China; Key Laboratory of Convergence Medical Engineering System and Healthcare Technology, The Ministry of Industry and Information Technology, Beijing Institute of Technology, China
| | - Huiwu Dong
- Department of Ultrasound Diagnosis, Chinese PLA General Hospital, China
| | - Yilun Zhang
- School of Life Science, Beijing Institute of Technology, Beijing, 100081, China
| | - Jianyong Wei
- School of Life Science, Beijing Institute of Technology, Beijing, 100081, China
| | - Paul N Watton
- Department of Computer Science & INSIGNEO Institute, University of Sheffield, UK; Department of Mechanical Engineering and Material Science, University of Pittsburgh, United States
| | - Wei Guo
- Department of Vascular and Endovascular Surgery, Chinese PLA General Hospital, Beijing 100853, China
| | - Duanduan Chen
- School of Life Science, Beijing Institute of Technology, Beijing, 100081, China; Key Laboratory of Convergence Medical Engineering System and Healthcare Technology, The Ministry of Industry and Information Technology, Beijing Institute of Technology, China.
| | - Jiang Xiong
- Department of Vascular and Endovascular Surgery, Chinese PLA General Hospital, Beijing 100853, China.
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13
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Barber T. Wall shear stress and near-wall flows in the stenosed femoral artery. Comput Methods Biomech Biomed Engin 2017; 20:1048-1055. [DOI: 10.1080/10255842.2017.1331342] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Affiliation(s)
- T. Barber
- School of Mechanical & Manufacturing Engineering, University of New South Wales, Sydney, Australia
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14
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Sturm M, Lee H, Thomas S, Barber T. The haemodynamic effect of an adjustable band in an arteriovenous fistula. Comput Methods Biomech Biomed Engin 2017; 20:949-957. [DOI: 10.1080/10255842.2017.1315635] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Affiliation(s)
- M. Sturm
- School of Mechanical and Manufacturing Engineering, University of New South Wales, Sydney, Australia
| | - H. Lee
- Department of Surgery, Prince of Wales Hospital, Sydney, Australia
| | - S. Thomas
- Department of Surgery, Prince of Wales Hospital, Sydney, Australia
- The Vascular Institute, Prince of Wales Hospital, Sydney, Australia
- Faculty of Medicine, University of New South Wales, Sydney, Australia
| | - T. Barber
- School of Mechanical and Manufacturing Engineering, University of New South Wales, Sydney, Australia
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15
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Javadzadegan A, Myo Lwin N, Asyraf M, Simmons A, Barber T. Analysis of Blood Flow Characteristics in a Model of a Mature Side-to-Side Arteriovenous Fistula. Artif Organs 2017; 41:E251-E262. [DOI: 10.1111/aor.12879] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2016] [Revised: 09/17/2016] [Accepted: 09/21/2016] [Indexed: 12/26/2022]
Affiliation(s)
- Ashkan Javadzadegan
- ANZAC Research Institute, The University of Sydney; Sydney
- Faculty of Medicine and Health Sciences; Macquarie University; Sydney
| | - Nay Myo Lwin
- School of Mechanical and Manufacturing Engineering; The University of New South Wales; Sydney, Australia
| | - Muhammad Asyraf
- School of Mechanical and Manufacturing Engineering; The University of New South Wales; Sydney, Australia
| | - Anne Simmons
- School of Mechanical and Manufacturing Engineering; The University of New South Wales; Sydney, Australia
| | - Tracie Barber
- School of Mechanical and Manufacturing Engineering; The University of New South Wales; Sydney, Australia
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16
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Javadzadegan A, Lotfi A, Simmons A, Barber T. Haemodynamic analysis of femoral artery bifurcation models under different physiological flow waveforms. Comput Methods Biomech Biomed Engin 2015; 19:1143-53. [DOI: 10.1080/10255842.2015.1113406] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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17
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Javadzadegan A, Simmons A, Barber T. Spiral blood flow in aorta-renal bifurcation models. Comput Methods Biomech Biomed Engin 2015; 19:964-76. [PMID: 26414530 DOI: 10.1080/10255842.2015.1082552] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
The presence of a spiral arterial blood flow pattern in humans has been widely accepted. It is believed that this spiral component of the blood flow alters arterial haemodynamics in both positive and negative ways. The purpose of this study was to determine the effect of spiral flow on haemodynamic changes in aorta-renal bifurcations. In this regard, a computational fluid dynamics analysis of pulsatile blood flow was performed in two idealised models of aorta-renal bifurcations with and without flow diverter. The results show that the spirality effect causes a substantial variation in blood velocity distribution, while causing only slight changes in fluid shear stress patterns. The dominant observed effect of spiral flow is on turbulent kinetic energy and flow recirculation zones. As spiral flow intensity increases, the rate of turbulent kinetic energy production decreases, reducing the region of potential damage to red blood cells and endothelial cells. Furthermore, the recirculation zones which form on the cranial sides of the aorta and renal artery shrink in size in the presence of spirality effect; this may lower the rate of atherosclerosis development and progression in the aorta-renal bifurcation. These results indicate that the spiral nature of blood flow has atheroprotective effects in renal arteries and should be taken into consideration in analyses of the aorta and renal arteries.
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Affiliation(s)
| | - Anne Simmons
- b School of Mechanical and Manufacturing Engineering , The University of New South Wales , Sydney , Australia
| | - Tracie Barber
- b School of Mechanical and Manufacturing Engineering , The University of New South Wales , Sydney , Australia
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