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Balasubramanya A, Maes L, Rega F, Mazzi V, Morbiducci U, Famaey N, Degroote J, Segers P. Hemodynamics and wall shear metrics in a pulmonary autograft: Comparing a fluid-structure interaction and computational fluid dynamics approach. Comput Biol Med 2024; 176:108604. [PMID: 38761502 DOI: 10.1016/j.compbiomed.2024.108604] [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: 01/23/2024] [Revised: 05/02/2024] [Accepted: 05/11/2024] [Indexed: 05/20/2024]
Abstract
OBJECTIVE In young patients, aortic valve disease is often treated by placement of a pulmonary autograft (PA) which adapts to its new environment through growth and remodeling. To better understand the hemodynamic forces acting on the highly distensible PA in the acute phase after surgery, we developed a fluid-structure interaction (FSI) framework and comprehensively compared hemodynamics and wall shear-stress (WSS) metrics with a computational fluid dynamic (CFD) simulation. METHODS The FSI framework couples a prestressed non-linear hyperelastic arterial tissue model with a fluid model using the in-house coupling code CoCoNuT. Geometry, material parameters and boundary conditions are based on in-vivo measurements. Hemodynamics, time-averaged WSS (TAWSS), oscillatory shear index (OSI) and topological shear variation index (TSVI) are evaluated qualitatively and quantitatively for 3 different sheeps. RESULTS Despite systolic-to-diastolic volumetric changes of the PA in the order of 20 %, the point-by-point correlation of TAWSS and OSI obtained through CFD and FSI remains high (r > 0.9, p < 0.01) for TAWSS and (r > 0.8, p < 0.01) for OSI). Instantaneous WSS divergence patterns qualitatively preserve similarities, but large deformations of the PA leads to a decrease of the correlation between FSI and CFD resolved TSVI (r < 0.7, p < 0.01). Moderate co-localization between FSI and CFD is observed for low thresholds of TAWSS and high thresholds of OSI and TSVI. CONCLUSION FSI might be warranted if we were to use the TSVI as a mechano-biological driver for growth and remodeling of PA due to varying intra-vascular flow structures and near wall hemodynamics because of the large expansion of the PA.
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Affiliation(s)
| | - Lauranne Maes
- Department of Mechanical Engineering, KU Leuven, Leuven, Belgium
| | - Filip Rega
- Cardiac Surgery, Department of Cardiovascular Sciences, KU Leuven, Belgium
| | - Valentina Mazzi
- PolitoBIOMed Lab, Department of Mechanical and Aerospace Engineering, Politecnico di Torino, Turin, Italy
| | - Umberto Morbiducci
- PolitoBIOMed Lab, Department of Mechanical and Aerospace Engineering, Politecnico di Torino, Turin, Italy
| | - Nele Famaey
- Department of Mechanical Engineering, KU Leuven, Leuven, Belgium
| | - Joris Degroote
- Department of Electromechanical Systems and Metal Engineering, Ghent University, Ghent, Belgium
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Han Q, Qiao L, Yin L, Sui X, Shao W, Wang Q. The effect of exercise training intervention for patients with abdominal aortic aneurysm on cardiovascular and cardiorespiratory variables: an updated meta-analysis of randomized controlled trials. BMC Cardiovasc Disord 2024; 24:80. [PMID: 38291355 PMCID: PMC10829311 DOI: 10.1186/s12872-024-03745-x] [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: 08/17/2023] [Accepted: 01/22/2024] [Indexed: 02/01/2024] Open
Abstract
OBJECTIVE The purpose of this meta-analysis was to evaluate the effect of exercise training intervention in patients with abdominal aortic aneurysm (AAA). METHODS Eight randomized controlled trials (RCTs) that recruited 588 AAA patients were extracted using 4 databases (PubMed, Embase, Wanfang Data, and Cochrane Library). Physiological and biochemistry parameters that included in this study are high-sensitivity C-reactive protein (hs-CRP), respiratory peak oxygen uptake rate (VO2peak), triglyceride (TG), total cholesterol (TC), anaerobic threshold (AT), the diameter of AAA, high density lipoprotein cholesterol (HDL), low density lipoprotein cholesterol (LDL), and matrix metalloproteinase-9 (MMP-9). Standard mean difference (SMD) was used to assess the between group effect. RESULTS This meta-analysis was synthesized with findings from RCTs and found that hs-CRP (SMD, - 0.56 mg/dL; 95% CI: - 0.90 to 0.22; P = 0.001), VO2peak (SMD, 0.4 mL/kg/min; 95% CI, 0.21 to 0.60; P < 0.001), TG (SMD, - 0.39 mg/dL; 95% CI: - 0.02 to 0.77; P = 0.04), and AT (SMD, 0.75 mL/kg/min; 95% CI, 0.54 to 0.96; P < 0.001) were significantly improved in the exercise groups, while the size of AAA (SMD, - 0.15; 95% CI: - 0.36 to 0.06; P = 0.15), TC (SMD, 0.16 mg/dL; 95% CI: - 0.10 to 0.42; P = 0.23), HDL/LDL ratio (SMD, - 0.06; 95% CI: - 0.32 to 0.20; P = 0.64), HDL (SMD, - 0.09; 95% CI: - 0.39 to 0.20; P = 0.54), LDL (SMD, 0.08; 95% CI: - 0.21 to 0.38; P = 0.59), and MMP-9 (SMD, - 0.23 mg/dL; 95% CI: - 0.53 to 0.06; P = 0.12) did not differ in the exercise groups compared with the controls. CONCLUSION Exercise intervention improved some of the CVD risk factors but not all, hs-CRP, VO2peak and AT were significantly improved after exercise intervention, while, changes of MMP-9, the size of AAA, and the overall lipids profile were not. Exercise intervention provides an additional solution for improving cardiorespiratory capacity and health status among AAA patients, and might lead to a delay of AAA progression.
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Affiliation(s)
- Qi Han
- Sports Nutrition Center, National Institute of Sports Medicine, Beijing, 100029, China
- Beijing Sport University, Beijing, 100084, China
| | - Li Qiao
- Beijing Competitor Sports Nutrition Research Institute, Beijing, 100029, China
| | - Li Yin
- Department of Vascular Surgery, The Second Affiliated Hospital of Zhejiang University, School of Medicine, Hangzhou, 310020, China
- Department of Surgery, Northwestern University, Chicago, IL, 60611, USA
| | - Xuemei Sui
- Department of Exercise Science, Arnold School of Public Health, University of South Carolina, Columbia, SC, 29208, USA
| | - Wenjuan Shao
- Beijing Sport University, Beijing, 100084, China
- Minzu University of China, Beijing, 100081, China
| | - Qirong Wang
- Sports Nutrition Center, National Institute of Sports Medicine, Beijing, 100029, China.
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Ma Z, Zhou Y, Li P, He W, Li M. Clinical application of four-dimensional flow cardiovascular magnetic resonance in Marfan syndrome: A systematic review and meta-analysis. Curr Probl Cardiol 2024; 49:102177. [PMID: 37913934 DOI: 10.1016/j.cpcardiol.2023.102177] [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: 10/27/2023] [Accepted: 10/28/2023] [Indexed: 11/03/2023]
Abstract
This study aims to fill this gap by assessing the application of 4D flow CMR in MFS through a systematic review and meta-analysis. We conducted a comprehensive search of databases from their inception to May 1, 2023. Eligibility criteria were established based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. The quality of studies was assessed using the Newcastle-Ottawa Scale (NOS), with studies scoring above five deemed high quality. Meta-analyses were performed using Stata 15.1 software. Nine studies were analyzed. Findings indicate MFS patients had increased vortex flow in the descending aorta (DAo), larger aortic root diameter (ARD) and Z-scores, lower inner wall shear stress (WSS) in the proximal descending aorta (pDAo), reduced in-plane rotational flow (IRF) in the aortic arch and proximal descending aorta (pDAo), and increased pulse wave velocity (PWV) in the ascending aorta (AAo) and DAo compared to healthy subjects. No significant difference in systolic flow reversal ratio was observed. Sensitivity analysis showed no heterogeneity and Egger's test revealed no publication bias. This meta-analysis underscores the effectiveness of 4D flow CMR in detecting MFS, particularly through indicators such as vortex flow, WSS, IRF, ARD, and PWV. The findings provide insights into diagnosing cardiovascular diseases and predicting cardiovascular events in MFS patients. Further case-control studies are needed to establish measurement standards and explore potential indicators for improved diagnosis and treatment of MFS.
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Affiliation(s)
- Zixuan Ma
- Second Clinical College, GuangZhou Medical University, Guangzhou, Guangdong, 510182, China
| | - Yuanxin Zhou
- Second Clinical College, GuangZhou Medical University, Guangzhou, Guangdong, 510182, China
| | - Pengpu Li
- College of Pharmacy, GuangZhou Medical University, Guangzhou, Guangdong, 510182, China
| | - Wenkai He
- Department of Cardiology, Guangzhou Institute of Cardiovascular Disease, Guangdong Key Laboratory of Vascular Diseases, The Second Affiliated Hospital, Guangzhou Medical University, No. 63 South Asian Games Road, Panyu District, Guangzhou, Guangdong, 510260, China.
| | - Mingyan Li
- Department of Cardiology, Guangzhou Institute of Cardiovascular Disease, Guangdong Key Laboratory of Vascular Diseases, The Second Affiliated Hospital, Guangzhou Medical University, No. 63 South Asian Games Road, Panyu District, Guangzhou, Guangdong, 510260, China.
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Ledda PG, Rossi T, Badas MG, Querzoli G. Can wall shear-stress topology predict proliferative vitreoretinopathy localization following pars plana vitrectomy? J Biomech 2024; 162:111914. [PMID: 38157782 DOI: 10.1016/j.jbiomech.2023.111914] [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: 09/21/2023] [Revised: 12/08/2023] [Accepted: 12/20/2023] [Indexed: 01/03/2024]
Abstract
We numerically study the fluid dynamics of oil tamponade in models of vitrectomized eyes prompted by a subset of daily activities corresponding to movements on the horizontal plane with the patient in a standing position. Bulk flow features are related to near-wall flow topology and transport at the retinal surface through a wall shear-stress-based analysis. Proliferative VitreoRetinopathy (PVR) is the leading cause of retinal re-detachment occurring in about 20% of all cases due to the accumulation of inflammatory cells in discrete retinal regions. Signalling soluble mediators stimulate inflammatory cells' chemotaxis and studying their distribution across the retinal surface may acquire clinical relevance. In all the investigated cases, persistent and elongated regions along the retina, potentially prone to accumulate chemo-attractants and cells are observed. Gradients of soluble inflammation mediators present in the aqueous are known responsible for the so-called epithelial-mesenchymal transition that initiates PVR and favours recurrent retinal detachment prompting the proliferation of inflammatory cells with collagen matrix deposition and its contraction. The surgical apposition of encircling scleral buckling elements, known for over a century to influence PVR formation and localization, modifies the attracting regions, possibly causing an accumulation of molecules and cells along approximately vertical lines that follow the rising menisci due to the cerclage indentation. The resulting spatial pattern is compatible with clinical observations. This study may open toward rational analyses of near-wall transport to predict PVR pathogenesis by relating biochemical accumulation in certain areas of the retina to clinical conditions.
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Affiliation(s)
- P G Ledda
- DICAAR, Università degli Studi di Cagliari, Cagliari, Italy
| | - T Rossi
- IRCCS Fondazione G.B. Bietti ONLUS, Rome, Italy
| | - M G Badas
- DICAAR, Università degli Studi di Cagliari, Cagliari, Italy
| | - G Querzoli
- DICAAR, Università degli Studi di Cagliari, Cagliari, Italy.
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Tsolaki E, Corso P, Zboray R, Avaro J, Appel C, Liebi M, Bertazzo S, Heinisch PP, Carrel T, Obrist D, Herrmann IK. Multiscale multimodal characterization and simulation of structural alterations in failed bioprosthetic heart valves. Acta Biomater 2023; 169:138-154. [PMID: 37517619 DOI: 10.1016/j.actbio.2023.07.044] [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: 02/27/2023] [Revised: 06/30/2023] [Accepted: 07/24/2023] [Indexed: 08/01/2023]
Abstract
Calcific degeneration is the most frequent type of heart valve failure, with rising incidence due to the ageing population. The gold standard treatment to date is valve replacement. Unfortunately, calcification oftentimes re-occurs in bioprosthetic substitutes, with the governing processes remaining poorly understood. Here, we present a multiscale, multimodal analysis of disturbances and extensive mineralisation of the collagen network in failed bioprosthetic bovine pericardium valve explants with full histoanatomical context. In addition to highly abundant mineralized collagen fibres and fibrils, calcified micron-sized particles previously discovered in native valves were also prevalent on the aortic as well as the ventricular surface of bioprosthetic valves. The two mineral types (fibres and particles) were detectable even in early-stage mineralisation, prior to any macroscopic calcification. Based on multiscale multimodal characterisation and high-fidelity simulations, we demonstrate that mineral occurrence coincides with regions exposed to high haemodynamic and biomechanical indicators. These insights obtained by multiscale analysis of failed bioprosthetic valves serve as groundwork for the evidence-based development of more durable alternatives. STATEMENT OF SIGNIFICANCE: Bioprosthetic valve calcification is a well-known clinically significant phenomenon, leading to valve failure. The nanoanalytical characterisation of bioprosthetic valves gives insights into the highly abundant, extensive calcification and disorganization of the collagen network and the presence of calcium phosphate particles previously reported in native cardiovascular tissues. While the collagen matrix mineralisation can be primarily attributed to a combination of chemical and mechanical alterations, the calcified particles are likely of host cellular origin. This work presents a straightforward route to mineral identification and characterization at high resolution and sensitivity, and with full histoanatomical context and correlation to hemodynamic and biomechanical indicators, hence providing design cues for improved bioprosthetic valve alternatives.
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Affiliation(s)
- Elena Tsolaki
- Laboratory for Particles-Biology Interactions, Department of Materials Meet Life, Swiss Federal Laboratories for Materials Science and Technology (Empa), Lerchenfeldstrasse 5, St. Gallen 9014, Switzerland; Nanoparticle Systems Engineering Laboratory, Department of Mechanical and Process Engineering, Institute of Energy and Process Engineering, ETH Zurich, Sonneggstrasse 3, Zurich 8092, Switzerland
| | - Pascal Corso
- ARTORG Center for Biomedical Engineering Research, University of Bern, Freiburgstrasse 3, Bern 3010, Switzerland
| | - Robert Zboray
- Center for X-Ray Analytics, Department of Materials Meet Life, Swiss Federal Laboratories for Materials Science and Technology (Empa), Ueberlandstrasse 129, Duebendorf 8600, Switzerland
| | - Jonathan Avaro
- Center for X-Ray Analytics, Department of Materials Meet Life, Swiss Federal Laboratories for Materials Science and Technology (Empa), Ueberlandstrasse 129, Duebendorf 8600, Switzerland
| | | | - Marianne Liebi
- Center for X-Ray Analytics, Department of Materials Meet Life, Swiss Federal Laboratories for Materials Science and Technology (Empa), Ueberlandstrasse 129, Duebendorf 8600, Switzerland; Paul Scherrer Institute, PSI, Villigen 5232, Switzerland; Department of Physics, Chalmers University of Technology, Gothenburg 41296, Sweden
| | - Sergio Bertazzo
- Department of Medical Physics and Biomedical Engineering, University College London, WC1E 6BT, UK; London Centre for Nanotechnology, University College London, WC1E 6BT, UK
| | - Paul Philipp Heinisch
- Department of Cardiovascular Surgery, Inselspital, University of Bern, Freiburgstrasse 18, Bern 3010, Switzerland; Department of Congenital and Pediatric Heart Surgery, German Heart Center Munich, Technische Universität München, Germany
| | - Thierry Carrel
- Department of Cardiovascular Surgery, Inselspital, University of Bern, Freiburgstrasse 18, Bern 3010, Switzerland; Department of Cardiac Surgery, University Hospital Zurich (USZ), Rämistrasse 101, Zürich 8091, Switzerland.
| | - Dominik Obrist
- ARTORG Center for Biomedical Engineering Research, University of Bern, Freiburgstrasse 3, Bern 3010, Switzerland.
| | - Inge K Herrmann
- Laboratory for Particles-Biology Interactions, Department of Materials Meet Life, Swiss Federal Laboratories for Materials Science and Technology (Empa), Lerchenfeldstrasse 5, St. Gallen 9014, Switzerland; Nanoparticle Systems Engineering Laboratory, Department of Mechanical and Process Engineering, Institute of Energy and Process Engineering, ETH Zurich, Sonneggstrasse 3, Zurich 8092, Switzerland.
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Hadad S, Rangwala SD, Stout JN, Mut F, Orbach DB, Cebral JR, See AP. Understanding development of jugular bulb stenosis in vein of galen malformations: identifying metrics of complex flow dynamics in the cerebral venous vasculature of infants. Front Physiol 2023; 14:1113034. [PMID: 37275225 PMCID: PMC10236198 DOI: 10.3389/fphys.2023.1113034] [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: 11/30/2022] [Accepted: 04/24/2023] [Indexed: 06/07/2023] Open
Abstract
Introduction: Computational fluid dynamics (CFD) assess biological systems based on specific boundary conditions. We propose modeling more advanced hemodynamic metrics, such as core line length (CL) and critical points which characterize complexity of flow in the context of cerebral vasculature, and specifically cerebral veins during the physiologically evolving early neonatal state of vein of Galen malformations (VOGM). CFD has not been applied to the study of arteriovenous shunting in Vein of Galen Malformations but could help illustrate the pathophysiology of this malformation. Methods: Three neonatal patients with VOGM at Boston Children's Hospital met inclusion criteria for this study. Structural MRI data was segmented to generate a mesh of the VOGM and venous outflow. Boundary condition flow velocity was derived from PC-MR sequences with arterial and venous dual velocity encoding. The mesh and boundary conditions were applied to model the cerebral venous flow. We computed flow variables including mean wall shear stress (WSSmean), mean OSI, CL, and the mean number of critical points (nCrPointsmean) for each patient specific model. A critical point is defined as the location where the shear stress vector field is zero (stationary point) and can be used to describe complexity of flow. Results: The division of flow into the left and right venous outflow was comparable between PC-MR and CFD modeling. A high complexity recirculating flow pattern observed on PC-MR was also identified on CFD modeling. Regions of similar WSSmean and OSImean (<1.3 fold) in the left and right venous outflow channels of a single patient have several-fold magnitude difference in higher order hemodynamic metrics (> 3.3 fold CL, > 1.7 fold nCrPointsmean). Specifically, the side which developed JBS in each model had greater nCrPointsmean compared to the jugular bulb with no stenosis (VOGM1: 4.49 vs. 2.53, VOGM2: 1.94 vs. 0, VOGM3: 1 vs. 0). Biologically, these regions had subsequently divergent development, with increased complexity of flow associating with venous stenosis. Discussion: Advanced metrics of flow complexity identified in computational models may reflect observed flow phenomena not fully characterized by primary or secondary hemodynamic parameters. These advanced metrics may indicate physiological states that impact development of jugular bulb stenosis in VOGM.
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Affiliation(s)
- Sara Hadad
- Department of Bioengineering, George Mason University, Fairfax, VA, United States
| | - Shivani D. Rangwala
- Cerebrovascular Surgery and Interventions Center, Department of Neurosurgery, Boston Children’s Hospital, Boston, MA, United States
- Department of Neurosurgery, University of Southern California LAC+USC, Los Angeles, CA, United States
| | - Jeffrey N. Stout
- Division of Newborn Medicine, Boston Children’s Hospital, Boston, MA, United States
| | - Fernando Mut
- Department of Bioengineering, George Mason University, Fairfax, VA, United States
| | - Darren B. Orbach
- Cerebrovascular Surgery and Interventions Center, Department of Neurosurgery, Boston Children’s Hospital, Boston, MA, United States
- Neurointerventional Radiology, Boston Children’s Hospital, Boston, MA, United States
| | - Juan R. Cebral
- Department of Bioengineering, George Mason University, Fairfax, VA, United States
| | - Alfred P. See
- Cerebrovascular Surgery and Interventions Center, Department of Neurosurgery, Boston Children’s Hospital, Boston, MA, United States
- Neurointerventional Radiology, Boston Children’s Hospital, Boston, MA, United States
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7
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Zalud NC, Bulusu KV, Plesniak MW. Shear stress metrics associated with pro-atherogenic high-risk anatomical features in a carotid artery bifurcation model. Clin Biomech (Bristol, Avon) 2023; 105:105956. [PMID: 37098301 DOI: 10.1016/j.clinbiomech.2023.105956] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/13/2022] [Revised: 04/06/2023] [Accepted: 04/13/2023] [Indexed: 04/27/2023]
Abstract
BACKGROUND Diseases associated with atherosclerotic plaques in the carotid artery are a major cause of deaths in the United States. Blood-flow-induced shear-stresses are known to trigger plaque formation. Prior literature suggests that the internal carotid artery sinus is prone to atherosclerosis, but there is limited understanding of why only certain patients are predisposed towards plaque formation. METHODS We computationally investigate the effect of vessel geometry on wall-shear-stress distribution by comparing flowfields and wall-shear-stress-metrics between a low-risk and a novel predisposed high-risk carotid artery bifurcation anatomy. Both models were developed based on clinical risk estimations and patient-averaged anatomical features. The high-risk geometry has a larger internal carotid artery branching angle and a lower internal-to-carotid-artery-diameter-ratio. A patient-averaged physiological carotid artery inflow waveform is used. FINDINGS The high-risk geometry experiences stronger flow separation in the sinus. Furthermore, it experiences a more equal flow split at the bifurcation, thereby reducing internal carotid artery flowrate and increasing atherosclerosis-prone low-velocity areas. Lowest time-averaged-wall-shear-stresses are present at the sinus outer wall, where plaques are often found, for both geometries. The high-risk geometry has significantly high, unfavorable oscillatory-shear-index values not found in the low-risk geometry. High oscillatory-shear-index areas are located at the vessels outside walls distal to the bifurcation and on the sinus wall. INTERPRETATION These results highlight the effectiveness of oscillatory-shear-index, to augment classical time-averaged-wall-shear-stress, in evaluating pro-atherogenic geometry features. Furthermore, the flow split at the bifurcation is a promising clinical indicator for atherosclerosis risk as it can be directly accessed using clinical imaging, whereas shear-stress-metrics cannot.
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Affiliation(s)
- Nora C Zalud
- Department of Mechanical and Aerospace Engineering, The George Washington University, 800 22nd Street NW, Science & Engineering Hall, Suite 3000, Washington, DC 20052, United States
| | - Kartik V Bulusu
- Department of Mechanical and Aerospace Engineering, The George Washington University, 800 22nd Street NW, Science & Engineering Hall, Suite 3000, Washington, DC 20052, United States
| | - Michael W Plesniak
- Department of Mechanical and Aerospace Engineering, The George Washington University, 800 22nd Street NW, Science & Engineering Hall, Suite 3000, Washington, DC 20052, United States; Department of Biomedical Engineering, The George Washington University, 800 22nd Street NW, Science & Engineering Hall, Suite 5000, Washington, DC 20052, United States.
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Sache A, Reymond P, Brina O, Jung B, Farhat M, Vargas MI. Near-wall hemodynamic parameters quantification in in vitro intracranial aneurysms with 7 T PC-MRI. MAGMA (NEW YORK, N.Y.) 2023; 36:295-308. [PMID: 37072539 PMCID: PMC10140017 DOI: 10.1007/s10334-023-01082-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/02/2022] [Revised: 03/20/2023] [Accepted: 03/21/2023] [Indexed: 04/20/2023]
Abstract
OBJECTIVE Wall shear stress (WSS) and its derived spatiotemporal parameters have proven to play a major role on intracranial aneurysms (IAs) growth and rupture. This study aims to demonstrate how ultra-high field (UHF) 7 T phase contrast magnetic resonance imaging (PC-MRI) coupled with advanced image acceleration techniques allows a highly resolved visualization of near-wall hemodynamic parameters patterns in in vitro IAs, paving the way for more robust risk assessment of their growth and rupture. MATERIALS AND METHODS We performed pulsatile flow measurements inside three in vitro models of patient-specific IAs using 7 T PC-MRI. To this end, we built an MRI-compatible test bench, which faithfully reproduced a typical physiological intracranial flow rate in the models. RESULTS The ultra-high field 7 T images revealed WSS patterns with high spatiotemporal resolution. Interestingly, the high oscillatory shear index values were found in the core of low WSS vortical structures and in flow stream intersecting regions. In contrast, maxima of WSS occurred around the impinging jet sites. CONCLUSIONS We showed that the elevated signal-to-noise ratio arising from 7 T PC-MRI enabled to resolve high and low WSS patterns with a high degree of detail.
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Affiliation(s)
- Antoine Sache
- Department of Mechanical Engineering, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland.
| | - Philippe Reymond
- Division of Neuroradiology, Geneva University Hospital, University of Geneva, Geneva, Switzerland
| | - Olivier Brina
- Division of Neuroradiology, Geneva University Hospital, University of Geneva, Geneva, Switzerland
| | - Bernd Jung
- Department of Diagnostic, Interventional and Paediatric Radiology, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
| | - Mohamed Farhat
- Department of Mechanical Engineering, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Maria Isabel Vargas
- Division of Neuroradiology, Geneva University Hospital, University of Geneva, Geneva, Switzerland
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Zhou M, Yu Y, Chen R, Liu X, Hu Y, Ma Z, Gao L, Jian W, Wang L. Wall shear stress and its role in atherosclerosis. Front Cardiovasc Med 2023; 10:1083547. [PMID: 37077735 PMCID: PMC10106633 DOI: 10.3389/fcvm.2023.1083547] [Citation(s) in RCA: 32] [Impact Index Per Article: 32.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2022] [Accepted: 03/09/2023] [Indexed: 04/05/2023] Open
Abstract
Atherosclerosis (AS) is the major form of cardiovascular disease and the leading cause of morbidity and mortality in countries around the world. Atherosclerosis combines the interactions of systemic risk factors, haemodynamic factors, and biological factors, in which biomechanical and biochemical cues strongly regulate the process of atherosclerosis. The development of atherosclerosis is directly related to hemodynamic disorders and is the most important parameter in the biomechanics of atherosclerosis. The complex blood flow in arteries forms rich WSS vectorial features, including the newly proposed WSS topological skeleton to identify and classify the WSS fixed points and manifolds in complex vascular geometries. The onset of plaque usually occurs in the low WSS area, and the plaque development alters the local WSS topography. low WSS promotes atherosclerosis, while high WSS prevents atherosclerosis. Upon further progression of plaques, high WSS is associated with the formation of vulnerable plaque phenotype. Different types of shear stress can lead to focal differences in plaque composition and to spatial variations in the susceptibility to plaque rupture, atherosclerosis progression and thrombus formation. WSS can potentially gain insight into the initial lesions of AS and the vulnerable phenotype that gradually develops over time. The characteristics of WSS are studied through computational fluid dynamics (CFD) modeling. With the continuous improvement of computer performance-cost ratio, WSS as one of the effective parameters for early diagnosis of atherosclerosis has become a reality and will be worth actively promoting in clinical practice. The research on the pathogenesis of atherosclerosis based on WSS is gradually an academic consensus. This article will comprehensively review the systemic risk factors, hemodynamics and biological factors involved in the formation of atherosclerosis, and combine the application of CFD in hemodynamics, focusing on the mechanism of WSS and the complex interactions between WSS and plaque biological factors. It is expected to lay a foundation for revealing the pathophysiological mechanisms related to abnormal WSS in the progression and transformation of human atherosclerotic plaques.
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Affiliation(s)
- Manli Zhou
- College of Traditional Chinese Medicine, Hunan University of Chinese Medicine, Changsha, China
| | - Yunfeng Yu
- College of Traditional Chinese Medicine, Hunan University of Chinese Medicine, Changsha, China
- The First Affiliated Hospital of Hunan University of Chinese Medicine, Changsha, China
| | - Ruiyi Chen
- The First Affiliated Hospital of Hunan University of Chinese Medicine, Changsha, China
| | - Xingci Liu
- College of Traditional Chinese Medicine, Hunan University of Chinese Medicine, Changsha, China
- The First Affiliated Hospital of Hunan University of Chinese Medicine, Changsha, China
| | - Yilei Hu
- College of Traditional Chinese Medicine, Hunan University of Chinese Medicine, Changsha, China
| | - Zhiyan Ma
- College of Traditional Chinese Medicine, Hunan University of Chinese Medicine, Changsha, China
| | - Lingwei Gao
- College of Traditional Chinese Medicine, Hunan University of Chinese Medicine, Changsha, China
| | - Weixiong Jian
- College of Traditional Chinese Medicine, Hunan University of Chinese Medicine, Changsha, China
- National Key Discipline of Traditional Chinese Medicine Diagnostics, Hunan Provincial Key Laboratory, Hunan University of Chinese Medicine, Changsha, China
- Correspondence: Weixiong Jian Liping Wang
| | - Liping Wang
- College of Rehabilitation Medicine and Health Care, Hunan University of Medicine, Huaihua, China
- Correspondence: Weixiong Jian Liping Wang
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Carpenter HJ, Ghayesh MH, Zander AC, Psaltis PJ. On the nonlinear relationship between wall shear stress topology and multi-directionality in coronary atherosclerosis. COMPUTER METHODS AND PROGRAMS IN BIOMEDICINE 2023; 231:107418. [PMID: 36842347 DOI: 10.1016/j.cmpb.2023.107418] [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: 11/02/2022] [Revised: 02/01/2023] [Accepted: 02/09/2023] [Indexed: 06/18/2023]
Abstract
BACKGROUND AND OBJECTIVE In this paper we investigate twelve multi-directional/topological wall shear stress (WSS) derived metrics and their relationships with the formation of coronary plaques in both computational fluid dynamics (CFD) and dynamic fluid-structure interaction (FSI) frameworks. While low WSS is one of the most established biomechanical markers associated with coronary atherosclerosis progression, alone it is limited. Multi-directional and topological WSS derived metrics have been shown to be important in atherosclerosis related mechanotransduction and near-wall transport processes. However, the relationships between these twelve WSS metrics and the influence of both FSI simulations and coronary dynamics is understudied. METHODS We first investigate the relationships between these twelve WSS derived metrics, stenosis percentage and lesion length through a parametric, transient CFD study. Secondly, we extend the parametric study to FSI, both with and without the addition of coronary dynamics, and assess their correlations. Finally, we present the case of a patient who underwent invasive coronary angiography and optical coherence tomography imaging at two time points 18 months apart. Associations between each of the twelve WSS derived metrics in CFD, static FSI and dynamic FSI simulations were assessed against areas of positive/negative vessel remodelling, and changes in plaque morphology. RESULTS 22-32% stenosis was the threshold beyond which adverse multi-directional/topological WSS results. Each metric produced a different relationship with changing stenoses and lesion length. Transient haemodynamics was impacted by coronary dynamics, with the topological shear variation index suppressed by up to 94%. These changes appear more critical at smaller stenosis levels, suggesting coronary dynamics could play a role in the earlier stages of atherosclerosis development. In the patient case, both dynamics and FSI vs CFD changes altered associations with measured changes in plaque morphology. An appendix of the linear fits between the various FSI- and CFD-based simulations is provided to assist in scaling CFD-based results to resemble the compliant walled characteristics of FSI more accurately. CONCLUSIONS These results highlight the potential for coronary dynamics to alter multi-directional/topological WSS metrics which could impact associations with changes in coronary atherosclerosis over time. These results warrant further investigation in a wider range of morphological settings and longitudinal cohort studies in the future.
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Affiliation(s)
- Harry J Carpenter
- School of Mechanical Engineering, University of Adelaide, Adelaide, South Australia 5005, Australia.
| | - Mergen H Ghayesh
- School of Mechanical Engineering, University of Adelaide, Adelaide, South Australia 5005, Australia.
| | - Anthony C Zander
- School of Mechanical Engineering, University of Adelaide, Adelaide, South Australia 5005, Australia
| | - Peter J Psaltis
- Vascular Research Centre, Lifelong Health Theme, South Australian Health and Medical Research Institute (SAHMRI), Adelaide, South Australia 5000, Australia; Adelaide Medical School, University of Adelaide, Adelaide, South Australia 5005, Australia; Department of Cardiology, Central Adelaide Local Health Network, Adelaide, South Australia 5000, Australia
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11
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Yang P, Zhang J, Xue J, Bai Y, Yang H, Zhang R, He B. Time domain adaptation of left ventricular diastolic intraventricular pressure in elite female ice hockey athletes. Front Cardiovasc Med 2023; 10:1057129. [PMID: 36865888 PMCID: PMC9971929 DOI: 10.3389/fcvm.2023.1057129] [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: 09/29/2022] [Accepted: 01/30/2023] [Indexed: 02/16/2023] Open
Abstract
Background Ice hockey is a high-intensity dynamic sport for which competitive athletes train for longer than 20 hours each week for several years. The cumulative time of myocardial exposure to hemodynamic stress affects cardiac remodeling. However, the intracardiac pressure distribution of the elite ice hockey athletes' heart during adaptation to long-term training remains to be explored. This study aimed to compare the diastolic intraventricular pressure difference (IVPD) of the left ventricle (LV) between healthy volunteers and ice hockey athletes with different training times. Methods Fifty-three female ice hockey athletes (27 elite and 26 casual) and 24 healthy controls were included. The diastolic IVPD of the LV during diastole was measured by vector flow mapping. The peak amplitude of the IVPD during isovolumic relaxation (P0), diastolic rapid filling (P1), and atrial systole (P4); the difference in the peak amplitude between adjacent phases (DiffP01, DiffP14); the time interval between the peak amplitude of adjacent phases (P0P1, P1P4); and the maximum decrease rate in diastolic IVPD were calculated. Differences between groups, as well as correlations between hemodynamic parameters and training time, were analyzed. Results Structural parameters of the LV were significantly higher in elite athletes than in casual players and controls. No significant difference in the peak amplitude of the IVPD during the diastolic phase was found among the three groups. The analysis of covariance with heart rate as a covariate showed that P1P4 in the elite athlete and casual player groups was significantly longer than that in the healthy control group (p < 0.001 for all). An increased P1P4 was significantly associated with an increased training year (β = 4.90, p < 0.001). Conclusions The diastolic cardiac hemodynamics of the LV in elite female ice hockey athletes could be characterized by a prolonged diastolic IVPD, and P1P4 prolonged with an increase in the training years, reflecting a time-domain adaptation in diastolic hemodynamics after long-term training.
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Affiliation(s)
- Ping Yang
- Postdoctoral Mobile Station of Sports Science, Chengdu Sport University, Chengdu, Sichuan, China
| | - Jianmei Zhang
- Institute of Sports Medicine, General Administration of Sport of China, Beijing, China
| | - Jun Xue
- National Emergency Medical Research Center, Emergency General Hospital, Beijing, China
| | - Yunfei Bai
- Institute of Sports Medicine, General Administration of Sport of China, Beijing, China
| | - Hui Yang
- Department of Physical Education, Jiangxi Science and Technology Normal University, Nanchang, Jiangxi, China
| | - Ruiping Zhang
- Institute of Sports Medicine, General Administration of Sport of China, Beijing, China
| | - Benxiang He
- Postdoctoral Mobile Station of Sports Science, Chengdu Sport University, Chengdu, Sichuan, China,*Correspondence: Benxiang He ✉
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Computer Modeling of Carotid Endarterectomy With the Different Shape Patches and Prediction of the Atherosclerotic Plaque Formation Zones. Curr Probl Cardiol 2023; 48:101505. [PMID: 36402216 DOI: 10.1016/j.cpcardiol.2022.101505] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2022] [Accepted: 11/11/2022] [Indexed: 11/18/2022]
Abstract
The article describes a method for constructing geometric models of the carotid bifurcation and computer simulation of endarterectomy surgery with the patches of various configurations. The purpose of this work is to identify the areas of the greatest risk of restenosis in the constructed models and to conduct a comparative analysis of risk factors when using the patches of different widths and shapes. The method is demonstrated on a reconstructed model of a healthy vessel. Its building is based on a preoperative computed tomography study of a particular patient's affected vessel. The flow in the vessel is simulated by computational fluid dynamics using data from the patient's ultrasound Doppler velocimetry. Risk factors are assessed through the hemodynamic indices on the vessel wall associated with Wall Shear Stress. The distribution of risk zones in the healthy vessel, presumably leading to its observed lesion (plaque), is analyzed. Comparative evaluation of 10 various patches implantation results is carried out and the optimal variant is determined. The proposed method can be used to predict the hemodynamic results of surgery using patches of various sizes and shapes.
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Wajihah SA, Sankar DS. A review on non-Newtonian fluid models for multi-layered blood rheology in constricted arteries. ARCHIVE OF APPLIED MECHANICS = INGENIEUR-ARCHIV 2023; 93:1771-1796. [PMID: 36743075 PMCID: PMC9886544 DOI: 10.1007/s00419-023-02368-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/05/2022] [Accepted: 01/13/2023] [Indexed: 06/18/2023]
Abstract
Haemodynamics is a branch of fluid mechanics which investigates the features of blood when it flows not only via blood vessels of smaller/larger diameter, but also under normal as well as abnormal flow states, such as in the presence of stenosis, aneurysm, and thrombosis. This review aims to discuss the rheological properties of blood, geometry of constrictions, dilations and the emergence of single-layered fluid to four-layered fluid models. To discuss further the influence of the aforesaid parameters on the physiologically important flow quantities, the mathematical formulation and solution methodology of the two-layered and four layered arterial blood flow problems studied by the authors (Afiqah and Sankar in ARPN J Eng Appl Sci 15:1129--1143, 2020, Comput Methods Programs Biomed 199:105907, 2021. 10.1016/j.cmpb.2020.105907) are recalled. It should be pointed out that the increasing resistive impedance to flow in three distinct states encompassing healthy, anaemic, and diabetic demonstrates that the greater the restriction in the artery, very few blood is carried to the pathetic organs, leading to subjects' death. It is also discovered that the pulsatile nature of blood movement produces a dynamic environment that poses a slew of intriguing and unstable fluid mechanical state. It is hoped that the intriguing results gathered from this literature survey and review conducted may help the medical practitioners to forecast blood behaviour mobility in stenotic arteries. Furthermore, the physiological information gathered from the available clinical data from the literature on patients diagnosed with diabetes and anaemia may be beneficial to doctors in deciding the therapeutic procedure for treating some particular cardiovascular disease.
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Affiliation(s)
- S. Afiqah Wajihah
- Applied Mathematics and Economics Programme Area, School of Applied Sciences and Mathematics, Universiti Teknologi Brunei, Jalan Tungku Link, Gadong, Bandar Seri Begawan, BE1410 Brunei Darussalam
| | - D. S. Sankar
- Applied Mathematics and Economics Programme Area, School of Applied Sciences and Mathematics, Universiti Teknologi Brunei, Jalan Tungku Link, Gadong, Bandar Seri Begawan, BE1410 Brunei Darussalam
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High-fidelity fluid structure interaction simulations of turbulent-like aneurysm flows reveals high-frequency narrowband wall vibrations: A stimulus of mechanobiological relevance? J Biomech 2022; 145:111369. [PMID: 36375263 DOI: 10.1016/j.jbiomech.2022.111369] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Revised: 10/19/2022] [Accepted: 10/30/2022] [Indexed: 11/06/2022]
Abstract
Recent high-fidelity/resolution computational fluid dynamics simulations of intracranial aneurysm hemodynamics have revealed turbulent-like flows. We hypothesized that the associated high-frequency pressure fluctuations could promote aneurysm wall vibrations. We performed fully coupled high-fidelity transient fluid structure interaction simulations between the blood flow and compliant aneurysm sac wall taking 5,000 time steps per second using a 3D patient-specific model previously shown to harbour turbulent-like flow. Our results show that the flow velocity contained fluctuations with a smooth and continuously decaying energy up to ∼160Hz, and fluctuating pressures with characteristic frequency peaks at approximately 30, 130 and 210Hz. There was a strong two-way coupling between the pressure and the wall deformation, for which the frequency spectrum showed similar characteristics, but with a narrow band peak at ∼120Hz with large regional differences in amplitude up to 80μm. The physics of the flow is broadly consistent with clinical reports of turbulent-like flows, while the physics of the wall is consistent with reports of spectral peaks in aneurysm patients. As many aneurysms are known to harbour turbulent-like flows, wall vibrations could be a widespread phenomenon. Finally, since aneurysms are vascular pathologies by definition and many/most aneurysms do not have endothelial cells but still display a focal remodeling, we hypothesize that vibrations and stresses within the wall itself might play a role in the mechanobiological processes of vessel wall pathology.
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Scarsoglio S, Saglietto A, Tripoli F, Zwanenburg JJM, Biessels GJ, De Ferrari GM, Anselmino M, Ridolfi L. Cerebral hemodynamics during atrial fibrillation: Computational fluid dynamics analysis of lenticulostriate arteries using 7 T high-resolution magnetic resonance imaging. PHYSICS OF FLUIDS (WOODBURY, N.Y. : 1994) 2022; 34:121909. [PMID: 36776539 PMCID: PMC9907777 DOI: 10.1063/5.0129899] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/07/2022] [Accepted: 11/26/2022] [Indexed: 06/18/2023]
Abstract
Atrial fibrillation (AF) is the most common cardiac arrhythmia, inducing irregular and faster heart beating. Aside from disabling symptoms-such as palpitations, chest discomfort, and reduced exercise capacity-there is growing evidence that AF increases the risk of dementia and cognitive decline, even in the absence of clinical strokes. Among the possible mechanisms, the alteration of deep cerebral hemodynamics during AF is one of the most fascinating and least investigated hypotheses. Lenticulostriate arteries (LSAs)-small perforating arteries perpendicularly departing from the anterior and middle cerebral arteries and supplying blood flow to basal ganglia-are especially involved in silent strokes and cerebral small vessel diseases, which are considered among the main vascular drivers of dementia. We propose for the first time a computational fluid dynamics analysis to investigate the AF effects on the LSAs hemodynamics by using 7 T high-resolution magnetic resonance imaging (MRI). We explored different heart rates (HRs)-from 50 to 130 bpm-in sinus rhythm and AF, exploiting MRI data from a healthy young male and internal carotid artery data from validated 0D cardiovascular-cerebral modeling as inflow condition. Our results reveal that AF induces a marked reduction of wall shear stress and flow velocity fields. This study suggests that AF at higher HR leads to a more hazardous hemodynamic scenario by increasing the atheromatosis and thrombogenesis risks in the LSAs region.
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Affiliation(s)
- S. Scarsoglio
- Department of Mechanical and Aerospace Engineering, Politecnico di Torino, Torino, Italy
| | - A. Saglietto
- Division of Cardiology, “Città della Salute e della Scienza di Torino” Hospital, Università di Torino, Torino, Italy
| | - F. Tripoli
- Department of Mechanical and Aerospace Engineering, Politecnico di Torino, Torino, Italy
| | - J. J. M. Zwanenburg
- Department of Radiology, University Medical Center Utrecht, Utrecht, The Netherlands
| | - G. J. Biessels
- Department of Neurology UMC Brain Center, University Medical Centre Utrecht, Utrecht, The Netherlands
| | - G. M. De Ferrari
- Division of Cardiology, “Città della Salute e della Scienza di Torino” Hospital, Università di Torino, Torino, Italy
| | - M. Anselmino
- Division of Cardiology, “Città della Salute e della Scienza di Torino” Hospital, Università di Torino, Torino, Italy
| | - L. Ridolfi
- Department of Environment, Land and Infrastructure Engineering, Politecnico di Torino, Torino, Italy
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16
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Mazzi V, De Nisco G, Calò K, Chiastra C, Daemen J, Steinman DA, Wentzel JJ, Morbiducci U, Gallo D. Divergence of the normalized wall shear stress as an effective computational template of low-density lipoprotein polarization at the arterial blood-vessel wall interface. COMPUTER METHODS AND PROGRAMS IN BIOMEDICINE 2022; 226:107174. [PMID: 36223707 DOI: 10.1016/j.cmpb.2022.107174] [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: 08/17/2022] [Revised: 09/20/2022] [Accepted: 10/03/2022] [Indexed: 06/16/2023]
Abstract
BACKGROUND AND OBJECTIVE Near-wall transport of low-density lipoproteins (LDL) in arteries plays a relevant role in the initiation of atherosclerosis. Although it can be modelled in silico by coupling the Navier-Stokes equations with the 3D advection-diffusion (AD) equation, the associated computational cost is high. As wall shear stress (WSS) represents a first-order approximation of the near-wall velocity in arteries, we aimed at identifying computationally convenient WSS-based quantities to infer LDL near-wall transport based on the underlying near-wall hemodynamics in five models of three human arterial districts (aorta, carotid bifurcations, coronary arteries). The simulated LDL transport and its WSS-based surrogates were qualitatively compared with in vivo longitudinal measurements of wall thickness growth on the coronary artery models. METHODS Numerical simulations of blood flow coupled with AD equations for LDL transport and blood-wall transfer were performed. The co-localization of the simulated LDL concentration polarization patterns with luminal surface areas characterized by low cycle-average WSS, near-wall flow stagnation and WSS attracting patterns was quantitatively assessed by the similarity index (SI). In detail, the latter two represent features of the WSS topological skeleton, obtained respectively through the Lagrangian tracking of surface-born particles, and the Eulerian analysis of the divergence of the normalized cycle-average WSS vector field. RESULTS Convergence of the solution of the AD problem required the simulation of 3 (coronary artery) to 10 (aorta) additional cardiac cycles with respect to the Navier-Stokes problem. Co-localization results underlined that WSS topological skeleton features indicating near-wall flow stagnation and WSS attracting patterns identified LDL concentration polarization profiles more effectively than low WSS, as indicated by higher SI values (SI range: 0.17-0.50 for low WSS; 0.24-0.57 for WSS topological skeleton features). Moreover, the correspondence between the simulated LDL uptake and WSS-based quantities profiles with the in vivo measured wall thickness growth in coronary arteries appears promising. CONCLUSIONS The recently introduced Eulerian approach for identifying WSS attracting patterns from the divergence of normalized WSS provides a computationally affordable template of the LDL polarization at the arterial blood-wall interface without simulating the AD problem. It thus candidates as an effective biomechanical tool for elucidating the mechanistic link amongst LDL transfer at the arterial blood-wall interface, WSS and atherogenesis.
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Affiliation(s)
- Valentina Mazzi
- PoliTo(BIO)Med Lab, Department of Mechanical and Aerospace Engineering, Politecnico di Torino, Turin, Italy
| | - Giuseppe De Nisco
- PoliTo(BIO)Med Lab, Department of Mechanical and Aerospace Engineering, Politecnico di Torino, Turin, Italy
| | - Karol Calò
- PoliTo(BIO)Med Lab, Department of Mechanical and Aerospace Engineering, Politecnico di Torino, Turin, Italy
| | - Claudio Chiastra
- PoliTo(BIO)Med Lab, Department of Mechanical and Aerospace Engineering, Politecnico di Torino, Turin, Italy
| | - Joost Daemen
- Department of Cardiology, Biomedical Engineering, Erasmus MC, 3000 CA Rotterdam, the Netherlands
| | - David A Steinman
- Biomedical Simulation Lab, Department of Mechanical and Industrial Engineering, University of Toronto, Toronto, Ontario, Canada
| | - Jolanda J Wentzel
- Department of Cardiology, Biomedical Engineering, Erasmus MC, 3000 CA Rotterdam, the Netherlands
| | - Umberto Morbiducci
- PoliTo(BIO)Med Lab, Department of Mechanical and Aerospace Engineering, Politecnico di Torino, Turin, Italy
| | - Diego Gallo
- PoliTo(BIO)Med Lab, Department of Mechanical and Aerospace Engineering, Politecnico di Torino, Turin, Italy.
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Dong L, Li H, Xu X, Ren M, Yu W, Bai W, Sun D, Tian J. Analysis of diastolic left ventricular wall shear stress in normal people of different age groups. Front Cardiovasc Med 2022; 9:953384. [PMID: 36211550 PMCID: PMC9537585 DOI: 10.3389/fcvm.2022.953384] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2022] [Accepted: 09/02/2022] [Indexed: 11/13/2022] Open
Abstract
Background Diastolic wall shear stress (WSS), assessed by using vector flow mapping (VFM), is the result of the interaction between the blood flow and the ventricular wall. This study aimed to evaluate the trend of left ventricular (LV) WSS in normal subjects. Methods and results A total of 371 healthy volunteers were recruited and divided into four age groups (group I: 18–30 years; group II: 31–43 years; group III: 44–56 years; group IV: 57–70 years). LV WSS of different age groups was measured at each diastolic phase (P1: isovolumic diastolic period, P2: rapid filling period, P3: slow filling period, and P4:atrial contraction period) to evaluate the change trend of LV WSS. In each age group, LV WSS coincided with a trend of increasing-decreasing-increasing during P1–P4 (P < 0.05). Besides, among groups I, II, III, and IV, WSS of anterolateral, inferoseptal, and anteroseptal in P1 and WSS of inferolateral, inferoseptal, and anteroseptal in P4 all showed an increasing trend with age (P < 0.05). Regarding sex differences, women had greater diastolic WSS compared to men (P < 0.05). Conclusion LV WSS showed a regular variation and had specific age- and sex-related patterns in different diastolic phases.
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Affiliation(s)
- Liping Dong
- Department of Ultrasound Medicine, The Second Affiliated Hospital of Harbin Medical University, Harbin Medical University, Harbin, China
| | - Hairu Li
- Department of Ultrasound Medicine, The Second Affiliated Hospital of Harbin Medical University, Harbin Medical University, Harbin, China
| | - Xiangli Xu
- Department of Ultrasound Medicine, The Second Hospital of Harbin, Harbin, China
| | - Min Ren
- Department of Ultrasound Medicine, Shanghai First Maternity and Infant Hospital, Tongji University School of Medicine, Shanghai, China
| | - Weidong Yu
- Department of Ultrasound Medicine, The Second Affiliated Hospital of Harbin Medical University, Harbin Medical University, Harbin, China
| | - Wenkun Bai
- Department of Ultrasound Medicine, Shanghai Sixth People’s Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Di Sun
- Department of Ultrasound Medicine, Shanghai Sixth People’s Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Jiawei Tian
- Department of Ultrasound Medicine, The Second Affiliated Hospital of Harbin Medical University, Harbin Medical University, Harbin, China
- *Correspondence: Jiawei Tian,
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Li X, Liu X, Deng X, Fan Y. Interplay between Artificial Intelligence and Biomechanics Modeling in the Cardiovascular Disease Prediction. Biomedicines 2022; 10:2157. [PMID: 36140258 PMCID: PMC9495955 DOI: 10.3390/biomedicines10092157] [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: 07/13/2022] [Revised: 08/26/2022] [Accepted: 08/28/2022] [Indexed: 11/16/2022] Open
Abstract
Cardiovascular disease (CVD) is the most common cause of morbidity and mortality worldwide, and early accurate diagnosis is the key point for improving and optimizing the prognosis of CVD. Recent progress in artificial intelligence (AI), especially machine learning (ML) technology, makes it possible to predict CVD. In this review, we first briefly introduced the overview development of artificial intelligence. Then we summarized some ML applications in cardiovascular diseases, including ML-based models to directly predict CVD based on risk factors or medical imaging findings and the ML-based hemodynamics with vascular geometries, equations, and methods for indirect assessment of CVD. We also discussed case studies where ML could be used as the surrogate for computational fluid dynamics in data-driven models and physics-driven models. ML models could be a surrogate for computational fluid dynamics, accelerate the process of disease prediction, and reduce manual intervention. Lastly, we briefly summarized the research difficulties and prospected the future development of AI technology in cardiovascular diseases.
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Affiliation(s)
- Xiaoyin Li
- Beijing Advanced Innovation Centre for Biomedical Engineering, Key Laboratory for Biomechanics and Mechanobiology of Chinese Education Ministry, School of Biological Science and Medical Engineering, Beihang University, Beijing 100083, China
| | - Xiao Liu
- Beijing Advanced Innovation Centre for Biomedical Engineering, Key Laboratory for Biomechanics and Mechanobiology of Chinese Education Ministry, School of Biological Science and Medical Engineering, Beihang University, Beijing 100083, China
| | - Xiaoyan Deng
- Beijing Advanced Innovation Centre for Biomedical Engineering, Key Laboratory for Biomechanics and Mechanobiology of Chinese Education Ministry, School of Biological Science and Medical Engineering, Beihang University, Beijing 100083, China
| | - Yubo Fan
- Beijing Advanced Innovation Centre for Biomedical Engineering, Key Laboratory for Biomechanics and Mechanobiology of Chinese Education Ministry, School of Biological Science and Medical Engineering, Beihang University, Beijing 100083, China
- School of Engineering Medicine, Beihang University, Beijing 100083, China
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Shar JA, Keswani SG, Grande-Allen KJ, Sucosky P. Significance of aortoseptal angle anomalies to left ventricular hemodynamics and subaortic stenosis: A numerical study. Comput Biol Med 2022; 146:105613. [PMID: 35751200 PMCID: PMC10570849 DOI: 10.1016/j.compbiomed.2022.105613] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2022] [Revised: 05/02/2022] [Accepted: 05/10/2022] [Indexed: 11/03/2022]
Abstract
PURPOSE Discrete subaortic stenosis (DSS) is an obstructive cardiac disease caused by a membranous lesion in the left ventricular (LV) outflow tract (LVOT). Although its etiology is unknown, the higher prevalence of DSS in LVOT anatomies featuring a steep aortoseptal angle (AoSA) suggests a potential role for hemodynamics. Therefore, the objective of this study was to quantify the impact of AoSA steepening on the LV three-dimensional (3D) hemodynamic stress environment. METHODS A 3D LV model reconstructed from cardiac cine-magnetic resonance imaging was connected to four LVOT geometrical variations spanning the clinical AoSA range (115°-160°). LV hemodynamic stresses were characterized in terms of cycle-averaged pressure, temporal shear magnitude (TSM), and oscillatory shear index. The wall shear stress (WSS) topological skeleton was further analyzed by computing the scaled divergence of the WSS vector field. RESULTS AoSA steepening caused an increasingly perturbed subaortic flow marked by LVOT flow skewness and complex 3D secondary flow patterns. These disturbances generated WSS overloads (>45% increase in TSM vs. 160° model) on the inferior LVOT wall, and increased WSS contraction (>66% decrease in WSS divergence vs. 160° model) in regions prone to DSS membrane formation. CONCLUSIONS AoSA steepening generated substantial hemodynamic stress abnormalities in LVOT regions prone to DSS formation. Further studies are needed to assess the possible impact of such mechanical abnormalities on the tissue and cellular responses.
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Affiliation(s)
- Jason A Shar
- Department of Mechanical Engineering, Kennesaw State University, 840 Polytechnic Lane, Marietta, GA, 30060, USA.
| | - Sundeep G Keswani
- Division of Pediatric Surgery, Texas Children's Hospital, Department of Surgery, Baylor College of Medicine, USA.
| | | | - Philippe Sucosky
- Department of Mechanical Engineering, Kennesaw State University, 840 Polytechnic Lane, Marietta, GA, 30060, USA.
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Li X, Liu X, Liang Y, Deng X, Fan Y. Spatiotemporal changes of local hemodynamics and plaque components during atherosclerotic progression in rabbit. COMPUTER METHODS AND PROGRAMS IN BIOMEDICINE 2022; 220:106814. [PMID: 35523025 DOI: 10.1016/j.cmpb.2022.106814] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Revised: 02/22/2022] [Accepted: 04/11/2022] [Indexed: 06/14/2023]
Abstract
BACKGROUND AND OBJECTIVE Recent evidence demonstrates that the atherogenic process is discontinuous. Our goal is to study changes of plaque components and local hemodynamics during atherosclerotic progression. METHODS The histological and immunohistochemical staining of high-fat diet rabbit aorta were evaluated at 0, 8, 10 and 12 weeks, respectively. In addition, the blood flow and LDL transport were simulated at the above four time points. RESULTS The plaque thickness at different characteristic regions increased at different rates. The collagen continued to increase, while the elastin, fibronectin, macrophages and smooth muscle cells increased first and then decreased. The relative surface LDL concentration decreased at 8 weeks, and then it increased first and decreased slightly. Meanwhile, the hemodynamic environment became better firstly at 8 weeks, then got slightly worse and lastly improved again. CONCLUSIONS The local hemodynamics and plaque components vary nonlinearly during atherosclerotic progression in rabbit aorta.
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Affiliation(s)
- Xiaoyin Li
- Beijing Advanced Innovation Centre for Biomedical Engineering, Key Laboratory for Biomechanics and Mechanobiology of Chinese Education Ministry, School of Biological Science and Medical Engineering, Beihang University, Beijing 100191, China
| | - Xiao Liu
- Beijing Advanced Innovation Centre for Biomedical Engineering, Key Laboratory for Biomechanics and Mechanobiology of Chinese Education Ministry, School of Biological Science and Medical Engineering, Beihang University, Beijing 100191, China.
| | - Ye Liang
- State Key Laboratory of Membrane Biology, School of Life Sciences, Peking University, Beijing, China
| | - Xiaoyan Deng
- Beijing Advanced Innovation Centre for Biomedical Engineering, Key Laboratory for Biomechanics and Mechanobiology of Chinese Education Ministry, School of Biological Science and Medical Engineering, Beihang University, Beijing 100191, China
| | - Yubo Fan
- Beijing Advanced Innovation Centre for Biomedical Engineering, Key Laboratory for Biomechanics and Mechanobiology of Chinese Education Ministry, School of Biological Science and Medical Engineering, Beihang University, Beijing 100191, China; School of Engineering Medicine, Beihang University, Beijing, China.
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21
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Mahmoudi M, Jennings C, Pereira K, Hall AF, Arzani A. Guiding the prostatic artery embolization procedure with computational uid dynamics. J Biomech Eng 2022; 144:1140781. [DOI: 10.1115/1.4054515] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2021] [Indexed: 11/08/2022]
Abstract
Abstract
Benign prostatic hyperplasia (BPH) is a common disease associated with lower urinary tract symptoms and the most frequent benign tumor in men. To reduce BPH therapy complications, prostatic artery embolization (PAE) was developed to replace the surgical options. PAE is a minimally invasive technique in which emboli are injected into the prostate arteries (PA), obstructing the blood flow in the hypervascular nodules. In this work, a personalized PAE treatment strategy was proposed using patient-specific computational fluid dynamics (CFD). First, the hemodynamics environment in the iliac arterial tree considering a large network of bifurcations was studied. The results showed complex blood flow patterns in the iliac arterial network. Subsequently, the transport of embolic particulates during PAE for the standard horizontal and a hypothetical vertical patient positioning was simulated using Lagrangian particle tracking. Emboli with different sizes were released at various locations across the iliac arterial tree. The emboli entering the PA were mapped back to their initial location to create emboli release maps (ERMs). The obtained ERMs during the standard patient positioning for smaller emboli at certain release locations showed distinct regions in which if the emboli were released within these regions, all of them would reach the PA without non-target embolization. During the hypothetical vertical patient positioning, the larger emboli formed a larger coherent region in the ERMs. Our patient-specific model can be used to find the best spatial location for emboli injection and perform the embolization procedure with minimal off-target delivery.
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Affiliation(s)
- Mostafa Mahmoudi
- Department of Mechanical Engineering, Northern Arizona University, Flagstaff, AZ, United States
| | - Chadrick Jennings
- Department of Mechanical Engineering, Northern Arizona University, Flagstaff, AZ, United States
| | - Keith Pereira
- Department of Radiology, Saint Louis University, St Louis, MO, United States
| | - Andrew F. Hall
- Department of Biomedical Engineering, Saint Louis University, St Louis, MO, United States
| | - Amirhossein Arzani
- Department of Mechanical Engineering, Northern Arizona University, Flagstaff, AZ, United States
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22
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He Y, Northrup H, Le H, Cheung AK, Berceli SA, Shiu YT. Medical Image-Based Computational Fluid Dynamics and Fluid-Structure Interaction Analysis in Vascular Diseases. Front Bioeng Biotechnol 2022; 10:855791. [PMID: 35573253 PMCID: PMC9091352 DOI: 10.3389/fbioe.2022.855791] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2022] [Accepted: 04/08/2022] [Indexed: 01/17/2023] Open
Abstract
Hemodynamic factors, induced by pulsatile blood flow, play a crucial role in vascular health and diseases, such as the initiation and progression of atherosclerosis. Computational fluid dynamics, finite element analysis, and fluid-structure interaction simulations have been widely used to quantify detailed hemodynamic forces based on vascular images commonly obtained from computed tomography angiography, magnetic resonance imaging, ultrasound, and optical coherence tomography. In this review, we focus on methods for obtaining accurate hemodynamic factors that regulate the structure and function of vascular endothelial and smooth muscle cells. We describe the multiple steps and recent advances in a typical patient-specific simulation pipeline, including medical imaging, image processing, spatial discretization to generate computational mesh, setting up boundary conditions and solver parameters, visualization and extraction of hemodynamic factors, and statistical analysis. These steps have not been standardized and thus have unavoidable uncertainties that should be thoroughly evaluated. We also discuss the recent development of combining patient-specific models with machine-learning methods to obtain hemodynamic factors faster and cheaper than conventional methods. These critical advances widen the use of biomechanical simulation tools in the research and potential personalized care of vascular diseases.
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Affiliation(s)
- Yong He
- Division of Vascular Surgery and Endovascular Therapy, University of Florida, Gainesville, FL, United States
| | - Hannah Northrup
- Department of Biomedical Engineering, University of Utah, Salt Lake City, UT, United States
- Division of Nephrology and Hypertension, Department of Internal Medicine, University of Utah, Salt Lake City, UT, United States
| | - Ha Le
- Division of Nephrology and Hypertension, Department of Internal Medicine, University of Utah, Salt Lake City, UT, United States
| | - Alfred K. Cheung
- Division of Nephrology and Hypertension, Department of Internal Medicine, University of Utah, Salt Lake City, UT, United States
- Veterans Affairs Salt Lake City Healthcare System, Salt Lake City, UT, United States
| | - Scott A. Berceli
- Division of Vascular Surgery and Endovascular Therapy, University of Florida, Gainesville, FL, United States
- Vascular Surgery Section, Malcom Randall Veterans Affairs Medical Center, Gainesville, FL, United States
| | - Yan Tin Shiu
- Division of Nephrology and Hypertension, Department of Internal Medicine, University of Utah, Salt Lake City, UT, United States
- Veterans Affairs Salt Lake City Healthcare System, Salt Lake City, UT, United States
- *Correspondence: Yan Tin Shiu,
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Obrist D, von Tengg-Kobligk H. Computational Fluid Dynamics (CFD) For Predicting Pathological Changes In The Aorta: Is It Ready For Clinical Use? Arq Bras Cardiol 2022; 118:461-462. [PMID: 35262581 PMCID: PMC8856675 DOI: 10.36660/abc.20220040] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Affiliation(s)
- Dominik Obrist
- ARTORG Center for Biomedical Engineering ResearchUniversity of BernBernSuíçaARTORG Center for Biomedical Engineering Research, University of Bern, Bern – Suíça
| | - Hendrik von Tengg-Kobligk
- Institute for Diagnostic, Interventional and Pediatric RadiologyUniversity of BernBernSuíçaInstitute for Diagnostic, Interventional and Pediatric Radiology (DIPR), University of Bern, Bern – Suíça
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24
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Volumetric lattice Boltzmann method for wall stresses of image-based pulsatile flows. Sci Rep 2022; 12:1697. [PMID: 35105911 PMCID: PMC8807599 DOI: 10.1038/s41598-022-05269-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2021] [Accepted: 12/23/2021] [Indexed: 11/18/2022] Open
Abstract
Image-based computational fluid dynamics (CFD) has become a new capability for determining wall stresses of pulsatile flows. However, a computational platform that directly connects image information to pulsatile wall stresses is lacking. Prevailing methods rely on manual crafting of a hodgepodge of multidisciplinary software packages, which is usually laborious and error-prone. We present a new computational platform, to compute wall stresses in image-based pulsatile flows using the volumetric lattice Boltzmann method (VLBM). The novelty includes: (1) a unique image processing to extract flow domain and local wall normality, (2) a seamless connection between image extraction and VLBM, (3) an en-route calculation of strain-rate tensor, and (4) GPU acceleration (not included here). We first generalize the streaming operation in the VLBM and then conduct application studies to demonstrate its reliability and applicability. A benchmark study is for laminar and turbulent pulsatile flows in an image-based pipe (Reynolds number: 10 to 5000). The computed pulsatile velocity and shear stress are in good agreements with Womersley's analytical solutions for laminar pulsatile flows and concurrent laboratory measurements for turbulent pulsatile flows. An application study is to quantify the pulsatile hemodynamics in image-based human vertebral and carotid arteries including velocity vector, pressure, and wall-shear stress. The computed velocity vector fields are in reasonably well agreement with MRA (magnetic resonance angiography) measured ones. This computational platform is good for image-based CFD with medical applications and pore-scale porous media flows in various natural and engineering systems.
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Chiastra C, Mazzi V, Lodi Rizzini M, Calò K, Corti A, Acquasanta A, De Nisco G, Belliggiano D, Cerrato E, Gallo D, Morbiducci U. Coronary Artery Stenting Affects Wall Shear Stress Topological Skeleton. J Biomech Eng 2022; 144:1131202. [PMID: 35015058 DOI: 10.1115/1.4053503] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2021] [Indexed: 01/09/2023]
Abstract
Despite the important advancements in the stent technology for the treatment of diseased coronary arteries, major complications still affect the post-operative long-term outcome. The stent-induced flow disturbances, and especially the altered wall shear stress (WSS) profile at the strut level, play an important role in the pathophysiological mechanisms leading to stent thrombosis (ST) and in-stent restenosis (ISR). In this context, the analysis of the WSS topological skeleton is gaining more and more interest by extending the current understanding of the association between local hemodynamics and vascular diseases. The present study aims to analyze the impact that a deployed coronary stent has on the WSS topological skeleton. Computational fluid dynamics simulations were performed in three stented human coronary artery geometries reconstructed from clinical images. The selected cases presented stents with different designs (i.e., two contemporary drug eluting stents and one bioresorbable scaffold) and included regions with stent malapposition or overlapping. A recently proposed Eulerian-based approach was applied to analyze the WSS topological skeleton features. The results highlighted that the presence of single or multiple stents within a coronary artery markedly impacts the WSS topological skeleton. In particular, repetitive patterns of WSS divergence were observed at the luminal surface, highlighting a WSS contraction action proximal to the struts and a WSS expansion action distal to the struts. This WSS action pattern was independent from the stent design. In conclusions, these findings could contribute to a deeper understanding of the hemodynamic-driven processes underlying ST and ISR.
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Affiliation(s)
- Claudio Chiastra
- PoliToBIOMed Lab, Department of Mechanical and Aerospace Engineering, Politecnico di Torino, Turin, Italy
| | - Valentina Mazzi
- PoliToBIOMed Lab, Department of Mechanical and Aerospace Engineering, Politecnico di Torino, Turin, Italy
| | - Maurizio Lodi Rizzini
- PoliToBIOMed Lab, Department of Mechanical and Aerospace Engineering, Politecnico di Torino, Turin, Italy
| | - Karol Calò
- PoliToBIOMed Lab, Department of Mechanical and Aerospace Engineering, Politecnico di Torino, Turin, Italy
| | - Anna Corti
- Laboratory of Biological Structure Mechanics (LaBS), Department of Chemistry, Materials and Chemical Engineering "Giulio Natta", Politecnico di Milano, Milan, Italy
| | - Alessandro Acquasanta
- PoliToBIOMed Lab, Department of Mechanical and Aerospace Engineering, Politecnico di Torino, Turin, Italy
| | - Giuseppe De Nisco
- PoliToBIOMed Lab, Department of Mechanical and Aerospace Engineering, Politecnico di Torino, Turin, Italy
| | - Davide Belliggiano
- Cardiology Division, San Luigi Gonzaga University Hospital, Orbassano, Turin, Italy
| | - Enrico Cerrato
- Interventional Cardiology Unit, San Luigi Gonzaga University Hospital, Orbassano, and Rivoli Infermi Hospital, Rivoli, Turin, Italy
| | - Diego Gallo
- PoliToBIOMed Lab, Department of Mechanical and Aerospace Engineering, Politecnico di Torino, Turin, Italy
| | - Umberto Morbiducci
- PoliToBIOMed Lab, Department of Mechanical and Aerospace Engineering, Politecnico di Torino, Turin, Italy
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Mazzi V, De Nisco G, Hoogendoorn A, Calò K, Chiastra C, Gallo D, Steinman DA, Wentzel JJ, Morbiducci U. Early Atherosclerotic Changes in Coronary Arteries are Associated with Endothelium Shear Stress Contraction/Expansion Variability. Ann Biomed Eng 2021; 49:2606-2621. [PMID: 34324092 PMCID: PMC8455396 DOI: 10.1007/s10439-021-02829-5] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Although unphysiological wall shear stress (WSS) has become the consensus hemodynamic mechanism for coronary atherosclerosis, the complex biomechanical stimulus affecting atherosclerosis evolution is still undetermined. This has motivated the interest on the contraction/expansion action exerted by WSS on the endothelium, obtained through the WSS topological skeleton analysis. This study tests the ability of this WSS feature, alone or combined with WSS magnitude, to predict coronary wall thickness (WT) longitudinal changes. Nine coronary arteries of hypercholesterolemic minipigs underwent imaging with local WT measurement at three time points: baseline (T1), after 5.6 ± 0.9 (T2), and 7.6 ± 2.5 (T3) months. Individualized computational hemodynamic simulations were performed at T1 and T2. The variability of the WSS contraction/expansion action along the cardiac cycle was quantified using the WSS topological shear variation index (TSVI). Alone or combined, high TSVI and low WSS significantly co-localized with high WT at the same time points and were significant predictors of thickening at later time points. TSVI and WSS magnitude values in a physiological range appeared to play an atheroprotective role. Both the variability of the WSS contraction/expansion action and WSS magnitude, accounting for different hemodynamic effects on the endothelium, (1) are linked to WT changes and (2) concur to identify WSS features leading to coronary atherosclerosis.
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Affiliation(s)
- Valentina Mazzi
- PoliToBIOMed Lab, Department of Mechanical and Aerospace Engineering, Politecnico di Torino, Corso Duca degli Abruzzi, 24, 10129, Turin, Italy
| | - Giuseppe De Nisco
- PoliToBIOMed Lab, Department of Mechanical and Aerospace Engineering, Politecnico di Torino, Corso Duca degli Abruzzi, 24, 10129, Turin, Italy
| | - Ayla Hoogendoorn
- Department of Cardiology, Biomedical Engineering, Erasmus MC, 3000 CA, Rotterdam, The Netherlands
| | - Karol Calò
- PoliToBIOMed Lab, Department of Mechanical and Aerospace Engineering, Politecnico di Torino, Corso Duca degli Abruzzi, 24, 10129, Turin, Italy
| | - Claudio Chiastra
- PoliToBIOMed Lab, Department of Mechanical and Aerospace Engineering, Politecnico di Torino, Corso Duca degli Abruzzi, 24, 10129, Turin, Italy
| | - Diego Gallo
- PoliToBIOMed Lab, Department of Mechanical and Aerospace Engineering, Politecnico di Torino, Corso Duca degli Abruzzi, 24, 10129, Turin, Italy
| | - David A Steinman
- Biomedical Simulation Laboratory, Department of Mechanical & Industrial Engineering, University of Toronto, Toronto, Canada
| | - Jolanda J Wentzel
- Department of Cardiology, Biomedical Engineering, Erasmus MC, 3000 CA, Rotterdam, The Netherlands
| | - Umberto Morbiducci
- PoliToBIOMed Lab, Department of Mechanical and Aerospace Engineering, Politecnico di Torino, Corso Duca degli Abruzzi, 24, 10129, Turin, Italy.
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Integrating multi-fidelity blood flow data with reduced-order data assimilation. Comput Biol Med 2021; 135:104566. [PMID: 34157468 DOI: 10.1016/j.compbiomed.2021.104566] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2021] [Revised: 05/30/2021] [Accepted: 06/08/2021] [Indexed: 11/20/2022]
Abstract
High-fidelity patient-specific modeling of cardiovascular flows and hemodynamics is challenging. Direct blood flow measurement inside the body with in-vivo measurement modalities such as 4D flow magnetic resonance imaging (4D flow MRI) suffer from low resolution and acquisition noise. In-vitro experimental modeling and patient-specific computational fluid dynamics (CFD) models are subject to uncertainty in patient-specific boundary conditions and model parameters. Furthermore, collecting blood flow data in the near-wall region (e.g., wall shear stress) with experimental measurement modalities poses additional challenges. In this study, a computationally efficient data assimilation method called reduced-order modeling Kalman filter (ROM-KF) was proposed, which combined a sequential Kalman filter with reduced-order modeling using a linear model provided by dynamic mode decomposition (DMD). The goal of ROM-KF was to overcome low resolution and noise in experimental and uncertainty in CFD modeling of cardiovascular flows. The accuracy of the method was assessed with 1D Womersley flow, 2D idealized aneurysm, and 3D patient-specific cerebral aneurysm models. Synthetic experimental data were used to enable direct quantification of errors using benchmark datasets. The accuracy of ROM-KF in reconstructing near-wall hemodynamics was assessed by applying the method to problems where near-wall blood flow data were missing in the experimental dataset. The ROM-KF method provided blood flow data that were more accurate than the computational and synthetic experimental datasets and improved near-wall hemodynamics quantification.
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28
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Choudhury S, Anupindi K, Patnaik BSV. A study on the transport and interaction between blood flow and low-density-lipoprotein in near-wall regions of blood vessels. Comput Methods Biomech Biomed Engin 2021; 24:1473-1487. [PMID: 33966566 DOI: 10.1080/10255842.2021.1893311] [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: 10/21/2022]
Abstract
Differences in the dynamics and transport of blood make certain regions of the arterial network the preferred sites for initiation and formation of arterial diseases like stenosis and aneurysms. Understanding of such arterial diseases is directly linked to critical hemodynamic parameters such as the wall shear stress (WSS). The present work generalises the influence of WSS on the concentration of LDL that was observed in an earlier study. To this end, a wide variety of simplified flow domain, inspired by the near-wall regions of aneurysms and stenosis, are constructed and analyzed. The effects of pulsatile inflow condition, rheology of blood and curvature of the wall on the correlation between WSS and LDL concentration are investigated. It is demonstrated that the time-scale of variation of lumen-surface-concentration (LSC) of LDL is larger than a single cardiac cycle. As a consequence, the time-average values of WSS are sufficient to locate the regions of higher LSC. This idea is strengthened by making use of simplified flow domain that generates moving stagnation point. Further, it was observed that the rheology of the blood and curvature of the wall does not affect the observed correlation between the WSS and LDL concentration.
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Affiliation(s)
- Satyajit Choudhury
- Department of Applied Mechanics, Indian Institute of Technology Madras, Chennai, India
| | - Kameswararao Anupindi
- Department of Mechanical Engineering, Indian Institute of Technology Madras, Chennai, India
| | - B S V Patnaik
- Department of Applied Mechanics, Indian Institute of Technology Madras, Chennai, India
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29
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Mahmoudi M, Farghadan A, McConnell DR, Barker AJ, Wentzel JJ, Budoff MJ, Arzani A. The Story of Wall Shear Stress in Coronary Artery Atherosclerosis: Biochemical Transport and Mechanotransduction. J Biomech Eng 2021; 143:041002. [PMID: 33156343 DOI: 10.1115/1.4049026] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Indexed: 12/20/2022]
Abstract
Coronary artery atherosclerosis is a local, multifactorial, complex disease, and the leading cause of death in the US. Complex interactions between biochemical transport and biomechanical forces influence disease growth. Wall shear stress (WSS) affects coronary artery atherosclerosis by inducing endothelial cell mechanotransduction and by controlling the near-wall transport processes involved in atherosclerosis. Each of these processes is controlled by WSS differently and therefore has complicated the interpretation of WSS in atherosclerosis. In this paper, we present a comprehensive theory for WSS in atherosclerosis. First, a short review of shear stress-mediated mechanotransduction in atherosclerosis was presented. Next, subject-specific computational fluid dynamics (CFD) simulations were performed in ten coronary artery models of diseased and healthy subjects. Biochemical-specific mass transport models were developed to study low-density lipoprotein, nitric oxide, adenosine triphosphate, oxygen, monocyte chemoattractant protein-1, and monocyte transport. The transport results were compared with WSS vectors and WSS Lagrangian coherent structures (WSS LCS). High WSS magnitude protected against atherosclerosis by increasing the production or flux of atheroprotective biochemicals and decreasing the near-wall localization of atherogenic biochemicals. Low WSS magnitude promoted atherosclerosis by increasing atherogenic biochemical localization. Finally, the attracting WSS LCS's role was more complex where it promoted or prevented atherosclerosis based on different biochemicals. We present a summary of the different pathways by which WSS influences coronary artery atherosclerosis and compare different mechanotransduction and biotransport mechanisms.
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Affiliation(s)
- Mostafa Mahmoudi
- Department of Mechanical Engineering, Northern Arizona University, Flagstaff, AZ 86011
| | - Ali Farghadan
- Department of Mechanical Engineering, Northern Arizona University, Flagstaff, AZ 86011
| | - Daniel R McConnell
- Department of Mechanical Engineering, Northern Arizona University, Flagstaff, AZ 86011
| | - Alex J Barker
- Department of Pediatric Radiology, University of Colorado Denver Anschutz Medical Campus, Aurora, CO 80045
| | - Jolanda J Wentzel
- Department of Cardiology, Biomedical Engineering, Erasmus MC, Rotterdam, The Netherlands
| | | | - Amirhossein Arzani
- Department of Mechanical Engineering, Northern Arizona University, Flagstaff, AZ 86011
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30
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Wall Shear Stress Topological Skeleton Analysis in Cardiovascular Flows: Methods and Applications. MATHEMATICS 2021. [DOI: 10.3390/math9070720] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
A marked interest has recently emerged regarding the analysis of the wall shear stress (WSS) vector field topological skeleton in cardiovascular flows. Based on dynamical system theory, the WSS topological skeleton is composed of fixed points, i.e., focal points where WSS locally vanishes, and unstable/stable manifolds, consisting of contraction/expansion regions linking fixed points. Such an interest arises from its ability to reflect the presence of near-wall hemodynamic features associated with the onset and progression of vascular diseases. Over the years, Lagrangian-based and Eulerian-based post-processing techniques have been proposed aiming at identifying the topological skeleton features of the WSS. Here, the theoretical and methodological bases supporting the Lagrangian- and Eulerian-based methods currently used in the literature are reported and discussed, highlighting their application to cardiovascular flows. The final aim is to promote the use of WSS topological skeleton analysis in hemodynamic applications and to encourage its application in future mechanobiology studies in order to increase the chance of elucidating the mechanistic links between blood flow disturbances, vascular disease, and clinical observations.
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31
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Santos GB, Oliveira I, Gasche JL, Militzer J, Baccin CE. Stent-Induced Vascular Remodeling in Two-Step Stent-Assisted Coiling Treatment of Brain Aneurysms: A Closer Look Into the Hemodynamic Changes During the Stent Healing Period. J Biomech Eng 2021; 143:031009. [PMID: 33006371 DOI: 10.1115/1.4048645] [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: 05/26/2020] [Indexed: 11/08/2022]
Abstract
Stenting has become an important adjunctive tool for assisting coil embolization in complex-shaped intracranial aneurysms. However, as a secondary effect, stent deployment has been related to both immediate and delayed remodeling of the local vasculature. Recent studies have demonstrated that this phenomenon may assume different roles depending on the treatment stage. However, the extent of such event on the intra-aneurysmal hemodynamics is still unclear; especially when performing two-step stent-assisted coiling (SAC). Therefore, we performed computational fluid dynamics (CFD) analysis of the blood flow in four bifurcation aneurysms focusing on the stent healing period found in SAC as a two-step maneuver. Our results show that by changing the local vasculature, the intra-aneurysmal hemodynamics changes considerably. However, even though changes do occur, they were not consistent among the cases. Furthermore, by changing the local vasculature not only the shear levels change but also the shear distribution on the aneurysm surface. Additionally, a geometric analysis alone can mislead the estimation of the novel hemodynamic environment after vascular remodeling, especially in the presence of mixing streams. Therefore, although the novel local vasculature might induce an improved hemodynamic environment, it is also plausible to expect that adverse hemodynamic conditions might occur. This could pose a particularly delicate condition since the aneurysm surface remains completely exposed to the novel hemodynamic environment during the stent healing period. Finally, our study emphasizes that vascular remodeling should be considered when assessing the hemodynamics in aneurysms treated with stents, especially when evaluating the earlier stages of the treatment process.
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Affiliation(s)
- Gabriel B Santos
- Department of Mechanical Engineering, School of Engineering, São Paulo State University (UNESP), Ilha Solteira, São Paulo 15385-000, Brazil
| | - Iago Oliveira
- Department of Mechanical Engineering, School of Engineering, São Paulo State University (UNESP), Ilha Solteira, São Paulo 15385-000, Brazil
| | - José L Gasche
- Department of Mechanical Engineering, School of Engineering, São Paulo State University (UNESP), Ilha Solteira, São Paulo 15385-000, Brazil
| | - Julio Militzer
- Department of Mechanical Engineering, Faculty of Engineering, Dalhousie University, Halifax, NS B3H 4R2, Canada
| | - Carlos E Baccin
- Interventional Neuroradiology, Hospital Israelita Albert Einstein, São Paulo, São Paulo 05652-900, Brazil
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Ahmadpour-B M, Nooraeen A, Tafazzoli-Shadpour M, Taghizadeh H. Contribution of atherosclerotic plaque location and severity to the near-wall hemodynamics of the carotid bifurcation: an experimental study and FSI modeling. Biomech Model Mechanobiol 2021; 20:1069-1085. [PMID: 33609192 DOI: 10.1007/s10237-021-01431-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Accepted: 02/03/2021] [Indexed: 01/22/2023]
Abstract
Atherosclerosis is initiated by endothelial injury that is related to abnormal values of hemodynamic parameters such as wall shear stress (WSS), oscillatory shear index (OSI) and stress phase angle (SPA), which are more common in arterial bifurcations due to the complex structure. An experimental model of human carotid bifurcation with accurate geometrical and mechanical features was set up, and using realistic pulsatile flow rates, the inlet and outlet pressure pulses were measured for normal and stenosed models with 40% and 80% severities at common carotid (CCA), internal carotid (ICA) and external carotid (ECA) arteries. Based on the obtained experimental data, fluid-structure models were developed to obtain WSS, OSI, and SPA and evaluate pathological consequences at different locations. Mild severity had minor impact, however, inducing severe 80% stenosis in each branch led to considerable localized changes of hemodynamic parameters both in the stenosis site and other locations. This included sharp increases in WSS values accompanied by very low values close to zero before and after the peaks. Severe stenosis not only caused significant changes in the local artery, but also in other branches. OSI and SPA were less sensitive to stenosis, although high peaks were observed on bifurcation site for the stenosis at ECA. The interconnection of arteries at carotid bifurcation results in altered pressure/flow patterns in all branches when a stenosis is applied in any site. Such effect confirms pathological findings that atherosclerotic plaques are observed simultaneously in different carotid branches, although with different degrees of plaque growth and severity.
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Affiliation(s)
- Mahyar Ahmadpour-B
- Cardiovascular Engineering Lab, Faculty of Biomedical Engineering, Amirkabir University of Technology, Tehran, Iran
| | - Ahmad Nooraeen
- Tissue Mechanics Lab, Faculty of Biomedical Engineering, Sahand University of Technology, Tabriz, Iran
| | - Mohammad Tafazzoli-Shadpour
- Cardiovascular Engineering Lab, Faculty of Biomedical Engineering, Amirkabir University of Technology, Tehran, Iran.
| | - Hadi Taghizadeh
- Tissue Mechanics Lab, Faculty of Biomedical Engineering, Sahand University of Technology, Tabriz, Iran.
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Wajihah S A, Sankar DS. Effects of porosity in four-layered non-linear blood rheology in constricted narrow arteries with clinical applications. COMPUTER METHODS AND PROGRAMS IN BIOMEDICINE 2021; 199:105907. [PMID: 33412286 DOI: 10.1016/j.cmpb.2020.105907] [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: 09/11/2020] [Accepted: 12/09/2020] [Indexed: 06/12/2023]
Abstract
BACKGROUND AND OBJECTIVE This study aims to investigate the haemodynamical factors with the motive to spell out some useful information for better interpretation and treatment of cardiovascular diseases. Numerous researchers theoretically investigated the movement of blood in the vascular system, treating blood as either single-layered or two-layered fluid representation. In this contemporary study, a four-layered fluid model is developed to analyse the rheological elements of blood when it flows via constricted arteries with slight constriction and the arterial wall is considered as porous medium. METHODS The momentum and constitutive equations are solved together with the suitable boundary conditions in an attempt to get the results on the distribution of velocity, volumetric flow rate, pressure gradient, shear stresses at the wall and resistive impedance to flow in which methods of integration and perturbation are utilized. The analytical/numerical solutions and graphical results are obtained by the extensive use of MATLAB software. RESULTS It is of importance to state that the magnitude of the shear stresses on the wall reduces with the rise of Darcy number, Weissenberg number and power law index. Velocity of blood however, rises with the upsurge in Darcy slip parameter, Weissenberg number and power law index. It is pertinent to record that when the stenosis depth rises from 0 to 0.15, the ratio of increase in the mean velocity of healthy, anemic and diabetic subjects are recorded as 4.58, 2.62 and 22.44 respectively. It is also found that the ratio of increase in the wall shear stress in the aforementioned states of blood are found to be 4.7, 4.27 and 3.62 respectively when the stenosis depth rises from 0 to 0.15. CONCLUSION The nature of increased flow resistance in all three different situations such as anemic, healthy, and diabetic shows that the larger the constriction in the artery, the less amount of blood is transported to crucial organs which results in the sudden death of subjects. It is hoped that the outcomes of this study would be useful to medical practitioners and bio-medical engineers in predicting the behavior of blood flow in narrowed blood vessels for a more probable treatment modalities.
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Affiliation(s)
- Afiqah Wajihah S
- Applied Mathematics and Economics Programme Area, School of Applied Sciences and Mathematics, Universiti Teknologi Brunei, Jalan Tungku Link, Gadong BE1410 Bandar Seri Begawan, Brunei Darussalam.
| | - D S Sankar
- Applied Mathematics and Economics Programme Area, School of Applied Sciences and Mathematics, Universiti Teknologi Brunei, Jalan Tungku Link, Gadong BE1410 Bandar Seri Begawan, Brunei Darussalam.
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Soltany Sadrabadi M, Hedayat M, Borazjani I, Arzani A. Fluid-structure coupled biotransport processes in aortic valve disease. J Biomech 2021; 117:110239. [PMID: 33515904 DOI: 10.1016/j.jbiomech.2021.110239] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2020] [Revised: 10/22/2020] [Accepted: 01/04/2021] [Indexed: 12/28/2022]
Abstract
Biological transport processes near the aortic valve play a crucial role in calcific aortic valve disease initiation and bioprosthetic aortic valve thrombosis. Hemodynamics coupled with the dynamics of the leaflets regulate these transport patterns. Herein, two-way coupled fluid-structure interaction (FSI) simulations of a 2D bicuspid aortic valve and a 3D mechanical heart valve were performed and coupled with various convective mass transport models that represent some of the transport processes in calcification and thrombosis. Namely, five different continuum transport models were developed to study biochemicals that originate from the blood and the leaflets, as well as residence-time and flow stagnation. Low-density lipoprotein (LDL) and platelet activation were studied for their role in calcification and thrombosis, respectively. Coherent structures were identified using vorticity and Lagrangian coherent structures (LCS) for the 2D and 3D models, respectively. A very close connection between vortex structures and biochemical concentration patterns was shown where different vortices controlled the concentration patterns depending on the transport mechanism. Additionally, the relationship between leaflet concentration and wall shear stress was revealed. Our work shows that blood flow physics and coherent structures regulate the flow-mediated biological processes that are involved in aortic valve calcification and thrombosis, and therefore could be used in the design process to optimize heart valve replacement durability.
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Affiliation(s)
| | - Mohammadali Hedayat
- J. Mike Walker '66 Department of Mechanical Engineering, Texas A&M University, College Station, TX, USA
| | - Iman Borazjani
- J. Mike Walker '66 Department of Mechanical Engineering, Texas A&M University, College Station, TX, USA
| | - Amirhossein Arzani
- Department of Mechanical Engineering, Northern Arizona University, Flagstaff, AZ, USA.
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Bruecker C, Li Q. Possible Early Generation of Physiological Helical Flow Could Benefit the Triflo Trileaflet Heart Valve Prosthesis Compared to Bileaflet Valves. Bioengineering (Basel) 2020; 7:bioengineering7040158. [PMID: 33302564 PMCID: PMC7763138 DOI: 10.3390/bioengineering7040158] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2020] [Revised: 11/17/2020] [Accepted: 12/07/2020] [Indexed: 11/16/2022] Open
Abstract
Background—Physiological helical flow in the ascending aorta has been well documented in the last two decades, accompanied by discussions on possible physiological benefits of such axial swirl. Recent 4D-MRI studies on healthy volunteers have found indications of early generation of helical flow, early in the systole and close to the valve plane. Objectives—Firstly, the aim of the study is to investigate the hypothesis of premature swirl existence in the ventricular outflow tract leading to helical flow in the valve plane, and second to investigate the possible impact of two different mechanical valve designs on the preservation of this early helical flow and its subsequent hemodynamic consequences. Methods—We use a pulse duplicator with an aortic arch and High-Speed Particle Image Velocimetry to document the flow evolution in the systolic cycle. The pulse-duplicator is modified with a swirl-generating insert to generate early helical flow in the valve plane. Special focus is paid to the interaction of such helical flow with different designs of mechanical prosthetic heart valves, comparing a classical bileaflet mechanical heart valve, the St. Jude Medical Regent valve (SJM Regent BMHV), with the Triflo trileaflet mechanical heart valve T2B version (Triflo TMHV). Results—When the swirl-generator is inserted, a vortex is generated in the core flow, demonstrating early helical flow in the valve plane, similar to the observations reported in the recent 4D-MRI study taken for comparison. For the Triflo trileaflet valve, the early helical flow is not obstructed in the central orifice, similar as in the case of the natural valve. Conservation of angular momentum leads to radial expansion of the core flow and flattening of the axial flow profile downstream in the arch. Furthermore, the early helical flow helps to overcome separation at the outer and inner curvature. In contrast, the two parallel leaflets for the bileaflet valve impose a flow straightener effect, annihilating the angular momentum, which has a negative impact on kinetic energy of the flow. Conclusion—The results imply better hemodynamics for the Triflo trileaflet valve based on hydrodynamic arguments under the discussed hypothesis. In addition, it makes the Triflo valve a better candidate for valve replacements in patients with a pathological generation of nonaxial velocity in the ventricle outflow tract.
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Mirramezani M, Shadden SC. A Distributed Lumped Parameter Model of Blood Flow. Ann Biomed Eng 2020; 48:2870-2886. [PMID: 32613457 PMCID: PMC7725998 DOI: 10.1007/s10439-020-02545-6] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2020] [Accepted: 06/03/2020] [Indexed: 01/02/2023]
Abstract
We propose a distributed lumped parameter (DLP) modeling framework to efficiently compute blood flow and pressure in vascular domains. This is achieved by developing analytical expressions describing expected energy losses along vascular segments, including from viscous dissipation, unsteadiness, flow separation, vessel curvature and vessel bifurcations. We apply this methodology to solve for unsteady blood flow and pressure in a variety of complex 3D image-based vascular geometries, which are typically approached using computational fluid dynamics (CFD) simulations. The proposed DLP framework demonstrated consistent agreement with CFD simulations in terms of flow rate and pressure distribution, with mean errors less than 7% over a broad range of hemodynamic conditions and vascular geometries. The computational cost of the DLP framework is orders of magnitude lower than the computational cost of CFD, which opens new possibilities for hemodynamics modeling in timely decision support scenarios, and a multitude of applications of imaged-based modeling that require ensembles of numerical simulations.
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Affiliation(s)
- Mehran Mirramezani
- Mechanical Engineering, University of California, Berkeley, CA, 94720, USA
- Mathematics, University of California, Berkeley, CA, 94720, USA
| | - Shawn C Shadden
- Mechanical Engineering, University of California, Berkeley, CA, 94720, USA.
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Plitman Mayo R, Yaakobovich H, Finkelstein A, Shadden SC, Marom G. Numerical models for assessing the risk of leaflet thrombosis post-transcatheter aortic valve-in-valve implantation. ROYAL SOCIETY OPEN SCIENCE 2020; 7:201838. [PMID: 33489295 PMCID: PMC7813235 DOI: 10.1098/rsos.201838] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/18/2020] [Accepted: 11/20/2020] [Indexed: 05/04/2023]
Abstract
Leaflet thrombosis has been suggested as the reason for the reduced leaflet motion in cases of hypoattenuated leaflet thickening of bioprosthetic aortic valves. This work aimed to estimate the risk of leaflet thrombosis in two post-valve-in-valve (ViV) configurations, using five different numerical approaches. Realistic ViV configurations were calculated by modelling the deployments of the latest version of transcatheter aortic valve devices (Medtronic Evolut PRO, Edwards SAPIEN 3) in the surgical Sorin Mitroflow. Computational fluid dynamics simulations of blood flow followed the dry models. Lagrangian and Eulerian measures of near-wall stagnation were implemented by particle and concentration tracking, respectively, to estimate the thrombogenicity and to predict the risk locations. Most of the numerical approaches indicate a higher leaflet thrombosis risk in the Edwards SAPIEN 3 device because of its intra-annular implantation. The Eulerian approaches estimated high-risk locations in agreement with the wall sheer stress (WSS) separation points. On the other hand, the Lagrangian approaches predicted high-risk locations at the proximal regions of the leaflets matching the low WSS magnitude regions of both transcatheter aortic valve implantation models and reported clinical and experimental data. The proposed methods can help optimizing future designs of transcatheter aortic valves with minimal thrombotic risks.
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Affiliation(s)
- Romina Plitman Mayo
- School of Mechanical Engineering, Tel Aviv University, Tel Aviv, Israel
- Department of Biological Regulation, Weizmann Institute of Science, Herzl Street 234, Rehovot, Israel
| | - Halit Yaakobovich
- Department of Biomedical Engineering, Tel Aviv University, Tel Aviv, Israel
| | | | - Shawn C. Shadden
- Department of Mechanical Engineering, University of California, Berkeley, CA, USA
| | - Gil Marom
- School of Mechanical Engineering, Tel Aviv University, Tel Aviv, Israel
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Sonmez UM, Cheng YW, Watkins SC, Roman BL, Davidson LA. Endothelial cell polarization and orientation to flow in a novel microfluidic multimodal shear stress generator. LAB ON A CHIP 2020; 20:4373-4390. [PMID: 33099594 PMCID: PMC7686155 DOI: 10.1039/d0lc00738b] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Endothelial cells (EC) respond to shear stress to maintain vascular homeostasis, and a disrupted response is associated with cardiovascular diseases. To understand how different shear stress modalities affect EC morphology and behavior, we developed a microfluidic device that concurrently generates three different levels of uniform wall shear stress (WSS) and six different WSS gradients (WSSG). In this device, human umbilical vein endothelial cells (HUVECs) exhibited a rapid and robust response to WSS, with the relative positioning of the Golgi and nucleus transitioning from a non-polarized to polarized state in a WSS magnitude- and gradient-dependent manner. By contrast, polarized HUVECs oriented their Golgi and nucleus polarity to the flow vector in a WSS magnitude-dependent manner, with positive WSSG inhibiting and negative WSSG promoting upstream orientation. Having validated this device, this chip can now be used to dissect the mechanisms underlying EC responses to different WSS modalities, including shear stress gradients, and to investigate the influence of flow on a diverse range of cells during development, homeostasis and disease.
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Affiliation(s)
- Utku M. Sonmez
- Department of Mechanical Engineering, Carnegie Mellon University, Pittsburgh, PA 15213, USA; Department of Human Genetics, Graduate School of Public Health, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - Ya-Wen Cheng
- Department of Bioengineering, Swanson School of Engineering, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - Simon C. Watkins
- Department of Cellular Biology, Center for Biologic Imaging, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - Beth L. Roman
- Department of Human Genetics, Graduate School of Public Health, University of Pittsburgh, Pittsburgh, PA 15261, USA; Vascular Medicine Institute, University of Pittsburgh School of Medicine, University of Pittsburgh, Pittsburgh, PA, 15261, USA
| | - Lance A. Davidson
- Department of Bioengineering, Swanson School of Engineering, University of Pittsburgh, Pittsburgh, PA 15261, USA; Department of Developmental Biology, University of Pittsburgh School of Medicine, University of Pittsburgh, Pittsburgh, PA 15261, USA; Department of Computational and Systems Biology, University of Pittsburgh School of Medicine, University of Pittsburgh, Pittsburgh, PA 15261, USA
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Michel JB. Phylogenic Determinants of Cardiovascular Frailty, Focus on Hemodynamics and Arterial Smooth Muscle Cells. Physiol Rev 2020; 100:1779-1837. [DOI: 10.1152/physrev.00022.2019] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
The evolution of the circulatory system from invertebrates to mammals has involved the passage from an open system to a closed in-parallel system via a closed in-series system, accompanying the increasing complexity and efficiency of life’s biological functions. The archaic heart enables pulsatile motion waves of hemolymph in invertebrates, and the in-series circulation in fish occurs with only an endothelium, whereas mural smooth muscle cells appear later. The present review focuses on evolution of the circulatory system. In particular, we address how and why this evolution took place from a closed, flowing, longitudinal conductance at low pressure to a flowing, highly pressurized and bifurcating arterial compartment. However, although arterial pressure was the latest acquired hemodynamic variable, the general teleonomy of the evolution of species is the differentiation of individual organ function, supported by specific fueling allowing and favoring partial metabolic autonomy. This was achieved via the establishment of an active contractile tone in resistance arteries, which permitted the regulation of blood supply to specific organ activities via its localized function-dependent inhibition (active vasodilation). The global resistance to viscous blood flow is the peripheral increase in frictional forces caused by the tonic change in arterial and arteriolar radius, which backscatter as systemic arterial blood pressure. Consequently, the arterial pressure gradient from circulating blood to the adventitial interstitium generates the unidirectional outward radial advective conductance of plasma solutes across the wall of conductance arteries. This hemodynamic evolution was accompanied by important changes in arterial wall structure, supported by smooth muscle cell functional plasticity, including contractility, matrix synthesis and proliferation, endocytosis and phagocytosis, etc. These adaptive phenotypic shifts are due to epigenetic regulation, mainly related to mechanotransduction. These paradigms actively participate in cardio-arterial pathologies such as atheroma, valve disease, heart failure, aneurysms, hypertension, and physiological aging.
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Morbiducci U, Mazzi V, Domanin M, De Nisco G, Vergara C, Steinman DA, Gallo D. Wall Shear Stress Topological Skeleton Independently Predicts Long-Term Restenosis After Carotid Bifurcation Endarterectomy. Ann Biomed Eng 2020; 48:2936-2949. [PMID: 32929560 PMCID: PMC7723943 DOI: 10.1007/s10439-020-02607-9] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2020] [Accepted: 09/02/2020] [Indexed: 12/26/2022]
Abstract
Wall Shear Stress (WSS) topological skeleton, composed by fixed points and the manifolds linking them, reflects the presence of blood flow features associated to adverse vascular response. However, the influence of WSS topological skeleton on vascular pathophysiology is still underexplored. This study aimed to identify direct associations between the WSS topological skeleton and markers of vascular disease from real-world clinical longitudinal data of long-term restenosis after carotid endarterectomy (CEA). Personalized computational hemodynamic simulations were performed on a cohort of 13 carotid models pre-CEA and at 1 month after CEA. At 60 months after CEA, intima-media thickness (IMT) was measured to detect long-term restenosis. The analysis of the WSS topological skeleton was carried out by applying a Eulerian method based on the WSS vector field divergence. To provide objective thresholds for WSS topological skeleton quantitative analysis, a computational hemodynamic dataset of 46 ostensibly healthy carotid bifurcation models was considered. CEA interventions did not completely restore physiological WSS topological skeleton features. Significant associations emerged between IMT at 60 months follow-up and the exposure to (1) high temporal variation of WSS contraction/expansion (R2 = 0.51, p < 0.05), and (2) high fixed point residence times, weighted by WSS contraction/expansion strength (R2 = 0.53, p < 0.05). These WSS topological skeleton features were statistically independent from the exposure to low WSS, a previously reported predictor of long-term restenosis, therefore representing different hemodynamic stimuli and potentially impacting differently the vascular response. This study confirms the direct association between WSS topological skeleton and markers of vascular disease, contributing to elucidate the mechanistic link between flow disturbances and clinical observations of vascular lesions.
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Affiliation(s)
- Umberto Morbiducci
- PolitoBIOMed Lab, Department of Mechanical and Aerospace Engineering, Politecnico di Torino, Corso Duca degli Abruzzi, 24, 10129, Turin, Italy
| | - Valentina Mazzi
- PolitoBIOMed Lab, Department of Mechanical and Aerospace Engineering, Politecnico di Torino, Corso Duca degli Abruzzi, 24, 10129, Turin, Italy
| | - Maurizio Domanin
- Department of Clinical Sciences and Community Health, Università di Milano, Milan, Italy.,Unità Operativa di Chirurgia Vascolare, Fondazione I.R.C.C.S. Cà Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - Giuseppe De Nisco
- PolitoBIOMed Lab, Department of Mechanical and Aerospace Engineering, Politecnico di Torino, Corso Duca degli Abruzzi, 24, 10129, Turin, Italy
| | - Christian Vergara
- Laboratory of Biological Structure Mechanics (LaBS), Dipartimento di Chimica, Materiali e Ingegneria Chimica ''Giulio Natta'', Politecnico di Milano, Milan, Italy
| | - David A Steinman
- Biomedical Simulation Laboratory, Department of Mechanical & Industrial Engineering, University of Toronto, Toronto, ON, Canada
| | - Diego Gallo
- PolitoBIOMed Lab, Department of Mechanical and Aerospace Engineering, Politecnico di Torino, Corso Duca degli Abruzzi, 24, 10129, Turin, Italy.
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Sheng X, Sheng Y, Gao S, Fan F, Wang J. Low fluid shear stress promoted ciliogenesis via Dvl2 in hUVECs. Histochem Cell Biol 2020; 154:639-654. [PMID: 32776193 DOI: 10.1007/s00418-020-01908-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/29/2020] [Indexed: 01/30/2023]
Abstract
This study aims to explore the mechanism of fluid shear stress in regulating the primary cilia assembly or disassembly in human umbilical vein endothelial cells (hUVECs) using microfluidic chamber experiments. Immunofluorescence analysis showed that primary cilia assembled under disturbed fluid shear stress (DF) of 1 dyne/cm2, while disassembled under unidirectional shear stress (USS) of 15 dynes/cm2. Disheveled (Dvl2) in Wnt signaling pathway was effectively co-immunoprecipitated with Bardet-Biedl syndrome proteins 8 (Bbs8) and γ-tubulin. Compared with those in the control group, the percentages of ciliated cells with Dvl2 overexpression were found to be 67% and 59.667%, respectively, under USS and DF (an increment of 21-38.7%); while, those with Dvl2 silencing were 16% and 32.667%, respectively, under USS and DF (a decrement of 23-30%). Further, the expression of Bbs8 and γ-tubulin was decreased by RNA interference of Dvl2 but increased with Dvl2 overexpression. The results indicated that Dvl2 played a pivotal role during DF-induced primary cilia assembly, and was important for apical docking of basal bodies through Bbs8 and γ-tubulin.
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Affiliation(s)
- Xin Sheng
- Department of Biochemistry, Zunyi Medical University, Zunyi, 563000, People's Republic of China.
| | - Yan Sheng
- Laboratory of Basic Medical Morphology, Zunyi Medical University, Zunyi, 563000, People's Republic of China
| | - Shuanglin Gao
- Department of Biochemistry, Zunyi Medical University, Zunyi, 563000, People's Republic of China
| | - Fang Fan
- Department of Biochemistry, Zunyi Medical University, Zunyi, 563000, People's Republic of China
| | - Junhua Wang
- Department of Biochemistry, Zunyi Medical University, Zunyi, 563000, People's Republic of China
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42
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Deciphering ascending thoracic aortic aneurysm hemodynamics in relation to biomechanical properties. Med Eng Phys 2020; 82:119-129. [DOI: 10.1016/j.medengphy.2020.07.003] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2020] [Revised: 06/19/2020] [Accepted: 07/09/2020] [Indexed: 12/20/2022]
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Salimi Ashkezari SF, Mut F, Chung BJ, Robertson AM, Cebral JR. Hemodynamic conditions that favor bleb formation in cerebral aneurysms. J Neurointerv Surg 2020; 13:231-236. [PMID: 32680874 PMCID: PMC8294198 DOI: 10.1136/neurintsurg-2020-016369] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2020] [Revised: 06/18/2020] [Accepted: 06/18/2020] [Indexed: 01/30/2023]
Abstract
BACKGROUND Although it is generally believed that blebs represent weaker spots in the walls of intracranial aneurysms (IAs), it is largely unknown which aneurysm characteristics favor their development. OBJECTIVE To investigate possible associations between aneurysm hemodynamic and geometric characteristics and the development of blebs in intracranial aneurysms. METHODS A total of 270 IAs in 199 patients selected for surgical clipping were studied. Blebs were visually identified and interactively marked on patient-specific vascular models constructed from presurgical images. Blebs were then deleted from the vascular reconstruction to approximate the aneurysm before bleb formation. Computational fluid dynamics studies were performed in these models and in cases without blebs. Hemodynamic and geometric characteristics of aneurysms with and without blebs were compared. RESULTS A total of 173 aneurysms had no blebs, while 97 aneurysms had a total of 122 blebs. Aneurysms favoring bleb formation had stronger (p<0.0001) and more concentrated inflow jets (p<0.0001), higher flow velocity (p=0.0061), more complex (p<0.0001) and unstable (p=0.0157) flow patterns, larger maximum wall shear stress (WSS; p<0.0001), more concentrated (p=0.0005) and oscillatory (p=0.0004) WSS distribution, and a more heterogeneous WSS field (p<0.0001), than aneurysms without blebs. They were also larger (p<0.0001), more elongated (p<0.0001), had wider necks (p=0.0002), and more distorted and irregular shapes (p<0.0001). CONCLUSIONS Strong and concentrated inflow jets, high-speed, complex, and unstable flow patterns, and concentrated, oscillatory, and heterogeneous WSS patterns favor the formation of blebs in IAs. Blebs are more likely to form in large, elongated, and irregularly shaped aneurysms. These adverse characteristics could be considered signs of aneurysm instability when evaluating aneurysms for conservative observation or treatment.
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Affiliation(s)
| | - Fernando Mut
- Department of Bioengineering, George Mason University, Fairfax, Virginia, USA
| | - Bong Jae Chung
- Department of Mathematical Sciences, Montclair State University, Montclair, New Jersey, USA
| | - Anne M Robertson
- Department of Mechanical Engineering and Material Science, University of Pittsburgh, Pittsburgh, Pennsylvania, USA.,Department of Bioengineering, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Juan R Cebral
- Department of Bioengineering, George Mason University, Fairfax, Virginia, USA.,Department of Mechanical Engineering, George Mason University, Fairfax, Virginia, USA
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Abstract
Dynamic mode decomposition (DMD) is a purely data-driven and equation-free technique for reduced-order modeling of dynamical systems and fluid flow. DMD finds a best fit linear reduced-order model that represents any given spatiotemporal data. In DMD, each mode evolves with a fixed frequency and therefore DMD modes represent physically meaningful structures that are ranked based on their dynamics. The application of DMD to patient-specific cardiovascular flow data is challenging. First, the input flow rate is unsteady and pulsatile. Second, the flow topology can change significantly in different phases of the cardiac cycle. Finally, blood flow in patient-specific diseased arteries is complex and often chaotic. The objective of this study was to overcome these challenges using our proposed multistage dynamic mode decomposition with control (mDMDc) method and use this technique to study patient-specific blood flow physics. The inlet flow rate was considered as the controller input to the systems. Blood flow data were divided into different stages based on the inlet flow waveform and DMD with control was applied to each stage. The system was augmented to consider both velocity and wall shear stress (WSS) vector data, and therefore study the interaction between the coherent structures in velocity and near-wall coherent structures in WSS. First, it was shown that DMD modes can exactly represent the analytical Womersley solution for incompressible pulsatile flow in tubes. Next, our method was applied to image-based coronary artery stenosis and cerebral aneurysm models where complex blood flow patterns are anticipated. The flow patterns were studied using the mDMDc modes and the reconstruction errors were reported. Our augmented mDMDc framework could capture coherent structures in velocity and WSS with a fewer number of modes compared to the traditional DMD approach and demonstrated a close connection between the velocity and WSS modes.
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Shear stress rosettes capture the complex flow physics in diseased arteries. J Biomech 2020; 104:109721. [PMID: 32151376 DOI: 10.1016/j.jbiomech.2020.109721] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2019] [Revised: 01/27/2020] [Accepted: 02/18/2020] [Indexed: 01/24/2023]
Abstract
Wall shear stress (WSS) is an important parameter in arterial mechanobiology. Various flow metrics, such as time averaged WSS (TAWSS), oscillatory shear index (OSI), and transWSS, have been used to characterize and relate possible WSS variations in arterial diseases like aneurysms and atherosclerosis. We use a graphical representation of WSS using shear rosettes to map temporal changes in the flow dynamics during a cardiac cycle at any spatial location on the vessel surface. The presence of secondary flows and flow reversals can be interpreted directly from the shape of the shear rosette. The mean WSS is given by the rosette centroid, the OSI by the splay around the rosette origin, and the transWSS by its width. We define a new metric, anisotropy ratio (AR), based on the ratio of the length to width of the shear rosette, to capture flow bi-directionality. We characterized the flow physics in controls and patient specific geometries of the ascending aorta (AA) and internal carotid artery (ICA) that have fundamentally different flow dynamics due to differences in the Reynolds and Womersley numbers. The differences in the flow dynamics are well reflected in the shapes of the WSS rosettes and the corresponding flow metrics.
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Particle transport and deposition correlation with near-wall flow characteristic under inspiratory airflow in lung airways. Comput Biol Med 2020; 120:103703. [PMID: 32217283 DOI: 10.1016/j.compbiomed.2020.103703] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2019] [Revised: 02/26/2020] [Accepted: 03/11/2020] [Indexed: 02/04/2023]
Abstract
Exposure of lung airways to detrimental suspended aerosols in the environment increases the vulnerability of the respiratory and cardiovascular systems. In addition, recent developments in therapeutic inhalation devices magnify the importance of particle transport. In this manuscript, particle transport and deposition patterns in the upper tracheobronchial (TB) tree were studied where the inertial forces are considerable for microparticles. Wall shear stress divergence (WSSdiv) is proposed as a wall-based parameter that can predict particle deposition patterns. WSSdiv is proportional to near-wall normal velocity and can quantify the strength of flow towards and away from the wall. Computational fluid dynamics (CFD) simulations were performed to quantify airflow velocity and WSS vectors for steady inhalation in one case-control and unsteady inhalation in six subject-specific airway trees. Turbulent flow simulation was performed for the steady case using large eddy simulation to study the effect of turbulence. Magnetic resonance velocimetry (MRV) measurements were used to validate the case-control CFD simulation. Inertial particle transport was modeled by solving the Maxey-Riley equation in a Lagrangian framework. Deposition percentage (DP) was quantified for the case-control model over five particle sizes. DP was found to be proportional to particle size in agreement with previous studies in the literature. A normalized deposition concentration (DC) was defined to characterize localized deposition. A relatively strong correlation (Pearson value > 0.7) was found between DC and positive WSSdiv for physiologically relevant Stokes (St) numbers. Additionally, a regional analysis was performed after dividing the lungs into smaller areas. A spatial integral of positive WSSdiv over each division was shown to maintain a very strong correlation (Pearson value > 0.9) with cumulative spatial DC or regional dosimetry. The conclusions were generalized to a larger population in which two healthy and four asthmatic patients were investigated. This study shows that WSSdiv could be used to predict the qualitative surface deposition and relative regional dosimetry without the need to solve a particle transport problem.
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Li Q, Hegner F, Bruecker CH. Comparative Study of Wall-Shear Stress at the Ascending Aorta for Different Mechanical Heart Valve Prostheses. J Biomech Eng 2020; 142:011006. [PMID: 30942828 DOI: 10.1115/1.4043357] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2018] [Indexed: 11/08/2022]
Abstract
An experimental study is reported which investigates the wall shear stress (WSS) distribution in a transparent model of the human aorta comparing an St. Jude Medical (SJM) Regent bileaflet mechanical heart valve (BMHV) with the Lapeyre-Triflo FURTIVA trileaflet mechanical heart valve (TMHV) in physiological pulsatile flow. Elastic microcantilever structures, calibrated as micropillar WSS sensors by microparticle-image-velocimetry measurements, are applied to the wall along the ascending aorta (AAo). The peak WSS values in the BMHV are observed to be almost twice that of the values seen in the TMHV. Flow field analysis illuminates that these peaks are linked to the jet-like flows generated in the valves interacting with the aortic wall. Not only the magnitude but also the impact regions are specific for different valve designs. The side-orifice jets generated by the BMHV travel along the aortic wall in the AAo, impacting the wall throughout the AAo. However, the jets generated by TMHV impact further downstream in the AAo and results in a reduced WSS.
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Affiliation(s)
- Qianhui Li
- School of Mathematics, Computer Science and Engineering, City, University of London, Northampton Square, London EC1V 0HB, UK
| | - Franziska Hegner
- Institute of Mechanics and Fluid Dynamics, Technical University Bergakademie Freiberg, Freiberg 09599, Germany
| | - Christoph H Bruecker
- School of Mathematics, Computer Science and Engineering, City, University of London, Northampton Square, London EC1V 0HB, UK
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Arzani A. Coronary artery plaque growth: A two-way coupled shear stress-driven model. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2020; 36:e3293. [PMID: 31820589 DOI: 10.1002/cnm.3293] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/29/2019] [Revised: 09/30/2019] [Accepted: 11/24/2019] [Indexed: 06/10/2023]
Abstract
Atherosclerosis in coronary arteries can lead to plaque growth, stenosis formation, and blockage of the blood flow supplying the heart tissue. Several studies have shown that hemodynamics play an important role in the growth of coronary artery plaques. Specifically, low wall shear stress (WSS) appears to be the leading hemodynamic parameter promoting atherosclerotic plaque growth, which in turn influences the blood flow and WSS distribution. Therefore, a two-way coupled interaction exists between WSS and atherosclerosis growth. In this work, a computational framework was developed to study the coupling between WSS and plaque growth in coronary arteries. Computational fluid dynamics (CFD) was used to quantify WSS distribution. Surface mesh nodes were moved in the inward normal direction according to a growth model based on WSS. After each growth stage, the geometry was updated and the CFD simulation repeated to find updated WSS values for the next growth stage. One hundred twenty growth stages were simulated in an idealized tube and an image-based left anterior descending artery. An automated framework was developed using open-source software to couple CFD simulations with growth. Changes in plaque morphology and hemodynamic patterns during different growth stages are presented. The results show larger plaque growth towards the downstream segment of the plaque, agreeing with the reported clinical observations. The developed framework could be used to establish hemodynamic-driven growth models and study the interaction between these processes.
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Affiliation(s)
- Amirhossein Arzani
- Department of Mechanical Engineering, Northern Arizona University, Flagstaff, Arizona
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Mazzi V, Gallo D, Calò K, Najafi M, Khan MO, De Nisco G, Steinman DA, Morbiducci U. A Eulerian method to analyze wall shear stress fixed points and manifolds in cardiovascular flows. Biomech Model Mechanobiol 2019; 19:1403-1423. [PMID: 31865482 DOI: 10.1007/s10237-019-01278-3] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2019] [Accepted: 12/08/2019] [Indexed: 12/12/2022]
Abstract
Based upon dynamical systems theory, a fixed point of a vector field such as the wall shear stress (WSS) at the luminal surface of a vessel is a point where the vector field vanishes. Unstable/stable manifolds identify contraction/expansion regions linking fixed points. The significance of such WSS topological features lies in their strong link with "disturbed" flow features like flow stagnation, separation and reversal, deemed responsible for vascular dysfunction initiation and progression. Here, we present a Eulerian method to analyze WSS topological skeleton through the identification and classification of WSS fixed points and manifolds in complex vascular geometries. The method rests on the volume contraction theory and analyzes the WSS topological skeleton through the WSS vector field divergence and Poincar[Formula: see text] index. The method is here applied to computational hemodynamics models of carotid bifurcation and intracranial aneurysm. An in-depth analysis of the time dependence of the WSS topological skeleton along the cardiac cycle is provided, enriching the information obtained from cycle-average WSS. Among the main findings, it emerges that on the carotid bifurcation, instantaneous WSS fixed points co-localize with cycle-average WSS fixed points for a fraction of the cardiac cycle ranging from 0 to [Formula: see text]; a persistent instantaneous WSS fixed point confined on the aneurysm dome does not co-localize with the cycle-average low-WSS region. In conclusion, the here presented approach shows the potential to speed up studies on the physiological significance of WSS topological skeleton in cardiovascular flows, ultimately increasing the chance of finding mechanistic explanations to clinical observations.
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Affiliation(s)
- Valentina Mazzi
- Department of Mechanical and Aerospace Engineering, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129, Turin, Italy
- PolitoBIOMed Lab, Politecnico di Torino, Turin, Italy
| | - Diego Gallo
- Department of Mechanical and Aerospace Engineering, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129, Turin, Italy
- PolitoBIOMed Lab, Politecnico di Torino, Turin, Italy
| | - Karol Calò
- Department of Mechanical and Aerospace Engineering, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129, Turin, Italy
- PolitoBIOMed Lab, Politecnico di Torino, Turin, Italy
| | - Mehdi Najafi
- Biomedical Simulation Laboratory, Department of Mechanical and Industrial Engineering, University of Toronto, Toronto, ON, Canada
| | | | - Giuseppe De Nisco
- Department of Mechanical and Aerospace Engineering, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129, Turin, Italy
- PolitoBIOMed Lab, Politecnico di Torino, Turin, Italy
| | - David A Steinman
- Biomedical Simulation Laboratory, Department of Mechanical and Industrial Engineering, University of Toronto, Toronto, ON, Canada
| | - Umberto Morbiducci
- Department of Mechanical and Aerospace Engineering, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129, Turin, Italy.
- PolitoBIOMed Lab, Politecnico di Torino, Turin, Italy.
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Simka M, Hobot J, Skuła M. Intraluminal thrombus in abdominal aortic aneurysm: a friend or a foe? INT ANGIOL 2019; 38:508-509. [PMID: 31782282 DOI: 10.23736/s0392-9590.19.04244-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Marian Simka
- Department of Anatomy, Institute of Medicine, University of Opole, Opole, Poland -
| | - Jacek Hobot
- Department of Anatomy, Institute of Medicine, University of Opole, Opole, Poland
| | - Marcin Skuła
- Department of Anatomy, Institute of Medicine, University of Opole, Opole, Poland
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