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Korte J, Klopp ES, Berg P. Multi-Dimensional Modeling of Cerebral Hemodynamics: A Systematic Review. Bioengineering (Basel) 2024; 11:72. [PMID: 38247949 PMCID: PMC10813503 DOI: 10.3390/bioengineering11010072] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2023] [Revised: 12/23/2023] [Accepted: 01/06/2024] [Indexed: 01/23/2024] Open
Abstract
The Circle of Willis (CoW) describes the arterial system in the human brain enabling the neurovascular blood supply. Neurovascular diseases like intracranial aneurysms (IAs) can occur within the CoW and carry the risk of rupture, which can lead to subarachnoid hemorrhage. The assessment of hemodynamic information in these pathologies is crucial for their understanding regarding detection, diagnosis and treatment. Multi-dimensional in silico approaches exist to evaluate these hemodynamics based on patient-specific input data. The approaches comprise low-scale (zero-dimensional, one-dimensional) and high-scale (three-dimensional) models as well as multi-scale coupled models. The input data can be derived from medical imaging, numerical models, literature-based assumptions or from measurements within healthy subjects. Thus, the most realistic description of neurovascular hemodynamics is still controversial. Within this systematic review, first, the models of the three scales (0D, 1D, 3D) and second, the multi-scale models, which are coupled versions of the three scales, were discussed. Current best practices in describing neurovascular hemodynamics most realistically and their clinical applicablility were elucidated. The performance of 3D simulation entails high computational expenses, which could be reduced by analyzing solely the region of interest in detail. Medical imaging to establish patient-specific boundary conditions is usually rare, and thus, lower dimensional models provide a realistic mimicking of the surrounding hemodynamics. Multi-scale coupling, however, is computationally expensive as well, especially when taking all dimensions into account. In conclusion, the 0D-1D-3D multi-scale approach provides the most realistic outcome; nevertheless, it is least applicable. A 1D-3D multi-scale model can be considered regarding a beneficial trade-off between realistic results and applicable performance.
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Affiliation(s)
- Jana Korte
- Research Campus STIMULATE, University of Magdeburg, 39106 Magdeburg, Germany
- Department of Fluid Dynamics and Technical Flows, University of Magdeburg, 39106 Magdeburg, Germany
| | - Ehlar Sophie Klopp
- Research Campus STIMULATE, University of Magdeburg, 39106 Magdeburg, Germany
- Department of Medical Engineering, University of Magdeburg, 39106 Magdeburg, Germany
| | - Philipp Berg
- Research Campus STIMULATE, University of Magdeburg, 39106 Magdeburg, Germany
- Department of Medical Engineering, University of Magdeburg, 39106 Magdeburg, Germany
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2
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Viola F, Del Corso G, De Paulis R, Verzicco R. GPU accelerated digital twins of the human heart open new routes for cardiovascular research. Sci Rep 2023; 13:8230. [PMID: 37217483 DOI: 10.1038/s41598-023-34098-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2022] [Accepted: 04/24/2023] [Indexed: 05/24/2023] Open
Abstract
The recruitment of patients for rare or complex cardiovascular diseases is a bottleneck for clinical trials and digital twins of the human heart have recently been proposed as a viable alternative. In this paper we present an unprecedented cardiovascular computer model which, relying on the latest GPU-acceleration technologies, replicates the full multi-physics dynamics of the human heart within a few hours per heartbeat. This opens the way to extensive simulation campaigns to study the response of synthetic cohorts of patients to cardiovascular disorders, novel prosthetic devices or surgical procedures. As a proof-of-concept we show the results obtained for left bundle branch block disorder and the subsequent cardiac resynchronization obtained by pacemaker implantation. The in-silico results closely match those obtained in clinical practice, confirming the reliability of the method. This innovative approach makes possible a systematic use of digital twins in cardiovascular research, thus reducing the need of real patients with their economical and ethical implications. This study is a major step towards in-silico clinical trials in the era of digital medicine.
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Affiliation(s)
- Francesco Viola
- Gran Sasso Science Institute (GSSI), L'Aquila, Italy
- INFN-Laboratori Nazionali del Gran Sasso, Assergi (AQ), Italy
| | - Giulio Del Corso
- Gran Sasso Science Institute (GSSI), L'Aquila, Italy
- Institute of Information Science and Technologies A. Faedo, CNR, Pisa, Italy
| | - Ruggero De Paulis
- European Hospital, Rome, Italy
- UniCamillus International University of Health Sciences, Rome, Italy
| | - Roberto Verzicco
- Gran Sasso Science Institute (GSSI), L'Aquila, Italy.
- University of Rome Tor Vergata, Rome, Italy.
- POF Group, University of Twente, Enschede, The Netherlands.
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3
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Dubs L, Charitatos V, Buoso S, Wegener S, Winklhofer S, Alkadhi H, Kurtcuoglu V. Assessment of extracranial carotid artery disease using digital twins - A pilot study. Neuroimage Clin 2023; 38:103435. [PMID: 37245493 PMCID: PMC10238877 DOI: 10.1016/j.nicl.2023.103435] [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: 01/19/2023] [Revised: 05/05/2023] [Accepted: 05/12/2023] [Indexed: 05/30/2023]
Abstract
To improve risk stratification in extracranial internal carotid artery disease (CAD), patients who would benefit maximally from revascularization must be identified. In cardiology, the fractional flow reserve (FFR) has become a reference standard for evaluating the functional severity of coronary artery stenosis, and noninvasive surrogates thereof relying on computational fluid dynamics (CFD) have been developed. Here, we present a CFD-based workflow using digital twins of patients' carotid bifurcations derived from computed tomography angiography for the noninvasive functional assessment of CAD. We reconstructed patient-specific digital twins of 37 carotid bifurcations. We implemented a CFD model using common carotid artery peak systolic velocity (PSV) acquired with Doppler ultrasound (DUS) as inlet boundary condition and a two-element Windkessel model as oulet boundary condition. The agreement between CFD and DUS on the PSV in the internal carotid artery (ICA) was then compared. The relative error for the agreement between DUS and CFD was 9% ± 20% and the intraclass correlation coefficient was 0.88. Furthermore, hyperemic simulations in a physiological range were feasible and unmasked markedly different pressure drops along two ICA stenoses with similar degree of narrowing under comparable ICA blood flow. Hereby, we lay the foundation for prospective studies on noninvasive CFD-based derivation of metrics similar to the FFR for the assessment of CAD.
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Affiliation(s)
- Linus Dubs
- University of Zurich, Institute of Physiology, The Interface Group, Winterthurerstrasse 190, 8057 Zürich, Switzerland.
| | - Vasileios Charitatos
- University of Zurich, Institute of Physiology, The Interface Group, Winterthurerstrasse 190, 8057 Zürich, Switzerland; University Hospital Zurich, University of Zurich, Institute of Diagnostic and Interventional Radiology, Rämistrasse 100, 8091 Zürich, Switzerland.
| | - Stefano Buoso
- University of Zurich, Institute of Physiology, The Interface Group, Winterthurerstrasse 190, 8057 Zürich, Switzerland; ETH Zurich, Institute for Biomedical Engineering, Gloriastrasse 35, 8092 Zürich, Switzerland.
| | - Susanne Wegener
- University Hospital Zurich, University of Zurich, Clinical Neuroscience Center, Department of Neurology, Frauenklinikstrasse 10, 8091 Zürich, Switzerland.
| | - Sebastian Winklhofer
- University Hospital Zurich, University of Zurich, Clinical Neuroscience Center, Department of Neuroradiology, Frauenklinikstrasse 10, 8091 Zürich, Switzerland.
| | - Hatem Alkadhi
- University Hospital Zurich, University of Zurich, Institute of Diagnostic and Interventional Radiology, Rämistrasse 100, 8091 Zürich, Switzerland.
| | - Vartan Kurtcuoglu
- University of Zurich, Institute of Physiology, The Interface Group, Winterthurerstrasse 190, 8057 Zürich, Switzerland.
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Belkacemi D, Tahar Abbes M, Al-Rawi M, Al-Jumaily AM, Bachene S, Laribi B. Intraluminal Thrombus Characteristics in AAA Patients: Non-Invasive Diagnosis Using CFD. Bioengineering (Basel) 2023; 10:bioengineering10050540. [PMID: 37237609 DOI: 10.3390/bioengineering10050540] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2023] [Revised: 04/24/2023] [Accepted: 04/25/2023] [Indexed: 05/28/2023] Open
Abstract
Abdominal aortic aneurysms (AAA) continue to pose a high mortality risk despite advances in medical imaging and surgery. Intraluminal thrombus (ILT) is detected in most AAAs and may critically impact their development. Therefore, understanding ILT deposition and growth is of practical importance. To assist in managing these patients, the scientific community has been researching the relationship between intraluminal thrombus (ILT) and hemodynamic parameters wall shear stress (WSS) derivatives. This study analyzed three patient-specific AAA models reconstructed from CT scans using computational fluid dynamics (CFD) simulations and a pulsatile non-Newtonian blood flow model. The co-localization and relationship between WSS-based hemodynamic parameters and ILT deposition were examined. The results show that ILT tends to occur in regions of low velocity and time-averaged WSS (TAWSS) and high oscillation shear index (OSI), endothelial cell activation potential (ECAP), and relative residence time (RRT) values. ILT deposition areas were found in regions of low TAWSS and high OSI independently of the nature of flow near the wall characterized by transversal WSS (TransWSS). A new approach is suggested which is based on the estimation of CFD-based WSS indices specifically in the thinnest and thickest ILT areas of AAA patients; this approach is promising and supports the effectiveness of CFD as a decision-making tool for clinicians. Further research with a larger patient cohort and follow-up data are needed to confirm these findings.
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Affiliation(s)
- Djelloul Belkacemi
- Mechanics and Energetics Laboratory, Hassiba Ben Bouali University, Chlef 02000, Algeria
- Unité de Développement des Equipements Solaires UDES, CDER, Bousmail, Tipaza 42415, Algeria
| | - Miloud Tahar Abbes
- Mechanics and Energetics Laboratory, Hassiba Ben Bouali University, Chlef 02000, Algeria
| | - Mohammad Al-Rawi
- Center for Engineering and Industrial Design, Waikato Institute of Technology, Hamilton 3240, New Zealand
| | - Ahmed M Al-Jumaily
- Institute of Biomedical Technologies, Auckland University of Technology, Auckland 1010, New Zealand
| | - Sofiane Bachene
- Radiologie, Centre d'Imagerie Médicale, Cheraga, Algiers 16000, Algeria
| | - Boualem Laribi
- FIMA Laboratory, Department of Technology, Djilali Bounaama University, Khemis Miliana 44225, Algeria
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Krzesiński P, Marczyk J, Wolszczak B, Gielerak GG, Accardi F. Quantitative Complexity Theory (QCT) in Integrative Analysis of Cardiovascular Hemodynamic Response to Posture Change. Life (Basel) 2023; 13:life13030632. [PMID: 36983787 PMCID: PMC10052206 DOI: 10.3390/life13030632] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2023] [Revised: 02/19/2023] [Accepted: 02/22/2023] [Indexed: 03/30/2023] Open
Abstract
The explanation of physiological mechanisms involved in adaptation of the cardiovascular system to intrinsic and environmental demands is crucial for both basic science and clinical research. Computational algorithms integrating multivariable data that comprehensively depict complex mechanisms of cardiovascular reactivity are currently being intensively researched. Quantitative Complexity Theory (QCT) provides quantitative and holistic information on the state of multi-functional dynamic systems. The present paper aimed to describe the application of QCT in an integrative analysis of the cardiovascular hemodynamic response to posture change. Three subjects that underwent head-up tilt testing under beat-by-beat hemodynamic monitoring (impedance cardiography) were discussed in relation to the complexity trends calculated using QCT software. Complexity has been shown to be a sensitive marker of a cardiovascular hemodynamic response to orthostatic stress and vasodilator administration, and its increase has preceded changes in standard cardiovascular parameters. Complexity profiling has provided a detailed assessment of individual hemodynamic patterns of syncope. Different stimuli and complexity settings produce results of different clinical usability.
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Affiliation(s)
- Paweł Krzesiński
- Departament of Cardiology and Internal Diseases, Military Institute of Medicine, 04-141 Warsaw, Poland
| | | | | | - Grzegorz Gerard Gielerak
- Departament of Cardiology and Internal Diseases, Military Institute of Medicine, 04-141 Warsaw, Poland
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Tricarico R, Berceli SA, Tran-Son-Tay R, He Y. Non-invasive estimation of the parameters of a three-element windkessel model of aortic arch arteries in patients undergoing thoracic endovascular aortic repair. Front Bioeng Biotechnol 2023; 11:1127855. [PMID: 36926690 PMCID: PMC10011467 DOI: 10.3389/fbioe.2023.1127855] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2022] [Accepted: 02/17/2023] [Indexed: 03/08/2023] Open
Abstract
Background: Image-based computational hemodynamic modeling and simulations are important for personalized diagnosis and treatment of cardiovascular diseases. However, the required patient-specific boundary conditions are often not available and need to be estimated. Methods: We propose a pipeline for estimating the parameters of the popular three-element Windkessel (WK3) models (a proximal resistor in series with a parallel combination of a distal resistor and a capacitor) of the aortic arch arteries in patients receiving thoracic endovascular aortic repair of aneurysms. Pre-operative and post-operative 1-week duplex ultrasound scans were performed to obtain blood flow rates, and intra-operative pressure measurements were also performed invasively using a pressure transducer pre- and post-stent graft deployment in arch arteries. The patient-specific WK3 model parameters were derived from the flow rate and pressure waveforms using an optimization algorithm reducing the error between simulated and measured pressure data. The resistors were normalized by total resistance, and the capacitor was normalized by total resistance and heart rate. The normalized WK3 parameters can be combined with readily available vessel diameter, brachial blood pressure, and heart rate data to estimate WK3 parameters of other patients non-invasively. Results: Ten patients were studied. The medians (interquartile range) of the normalized proximal resistor, distal resistor, and capacitor parameters are 0.10 (0.07-0.15), 0.90 (0.84-0.93), and 0.46 (0.33-0.58), respectively, for common carotid artery; 0.03 (0.02-0.04), 0.97 (0.96-0.98), and 1.91 (1.63-2.26) for subclavian artery; 0.18 (0.08-0.41), 0.82 (0.59-0.92), and 0.47 (0.32-0.85) for vertebral artery. The estimated pressure showed fairly high tolerance to patient-specific inlet flow rate waveforms using the WK3 parameters estimated from the medians of the normalized parameters. Conclusion: When patient-specific outflow boundary conditions are not available, our proposed pipeline can be used to estimate the WK3 parameters of arch arteries.
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Affiliation(s)
- Rosamaria Tricarico
- Department of Biomedical Engineering, University of Florida, Gainesville, FL, United States
| | - Scott A Berceli
- Division of Vascular Surgery and Endovascular Therapy, Department of Surgery, University of Florida, Gainesville, FL, United States.,North Florida/South Georgia Veterans Health System, Gainesville, FL, United States
| | - Roger Tran-Son-Tay
- Department of Biomedical Engineering, University of Florida, Gainesville, FL, United States.,Department of Mechanical and Aerospace Engineering, University of Florida, Gainesville, FL, United States
| | - Yong He
- Division of Vascular Surgery and Endovascular Therapy, Department of Surgery, University of Florida, Gainesville, FL, United States
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7
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Liu Y, Qing M, Zhao J, Huang B, Yang Y, Zheng T, Yuan D. Influence of severe neck angulation on hemodynamic and clinical outcomes following endovascular aneurysm repair: a hemodynamic analysis and a retrospective cohort study. Chin Med J (Engl) 2022; 135:2577-2584. [PMID: 36583921 PMCID: PMC9943978 DOI: 10.1097/cm9.0000000000002280] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2022] [Indexed: 12/31/2022] Open
Abstract
BACKGROUND For patients with severe neck angulation (SNA), hemodynamic and clinical outcomes following endovascular aneurysm repair (EVAR) are still unclear. This study aimed to explore the influence of SNA on hemodynamic and clinical outcomes following EVAR. METHODS This study included a hemodynamic analysis and a retrospective cohort study from West China Hospital of Sichuan University between January 2011 and December 2020. The Cox regression model, inverse probability of treatment weighting (IPTW) analysis, sensitivity analysis, and subgroup analysis were applied. Primary outcome was type IA endoleak (T1AEL). RESULTS In this hemodynamic analysis, nine non-severe neck angulation (nSNA) and 16 SNA idealized models were constructed. We found a significant difference in drag force between SNA and nSNA models (7.016 ± 2.579 N vs. 4.283 ± 1.460 N, P = 0.008), and proximal neck angles were significantly associated with the magnitude of drag force (F = 0.082 × α-0.006 × β + 2.818, α: 95% confidence interval [CI] 0.070-0.094; P = 0.001; β: 95% CI -0.019 to 0.007; P = 0.319). In our cohort study, 514 nSNA patients (71.5 ± 8.5 years; 459 males) and 208 SNA patients (72.5 ± 7.8 years; 135 males) were included, with a median follow-up duration of 34 months (16-63 months). All baseline characteristics were well balanced after IPTW matching. We found that SNA was associated with a significant risk of adverse limb event (hazard ratio [HR] 2.18, 95% CI 1.09-3.12), yet was not associated with T1AEL, overall survival, or reintervention. In patients without proximal or distal additional procedures (DAP), subgroup analyses suggested a significant risk of T1AEL (Proximal: HR 5.25, 95% CI 1.51-18.23; Distal: HR 5.07, 95% CI 1.60-16.07) and adverse limb event (Proximal: HR 2.27, 95% CI 1.01-5.07; Distal: HR 2.91, 95% CI 1.30-6.54) in SNA patients. However, no noticeable difference was observed in patients with proximal or DAP. CONCLUSIONS SNA has a critical influence on hemodynamic and clinical outcomes following EVAR. Appropriate additional procedures may be of great benefit to SNA patients.
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Affiliation(s)
- Yang Liu
- Department of Vascular Surgery, West China Hospital, Sichuan University, Chengdu, Sichuan 610041, China
| | - Ming Qing
- Department of Applied Mechanics, Sichuan University, Chengdu, Sichuan 610065, China
| | - Jichun Zhao
- Department of Vascular Surgery, West China Hospital, Sichuan University, Chengdu, Sichuan 610041, China
| | - Bin Huang
- Department of Vascular Surgery, West China Hospital, Sichuan University, Chengdu, Sichuan 610041, China
| | - Yi Yang
- Department of Vascular Surgery, West China Hospital, Sichuan University, Chengdu, Sichuan 610041, China
| | - Tinghui Zheng
- Department of Applied Mechanics, Sichuan University, Chengdu, Sichuan 610065, China
| | - Ding Yuan
- Department of Vascular Surgery, West China Hospital, Sichuan University, Chengdu, Sichuan 610041, China
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Computational Study of Abdominal Aortic Aneurysms with Severely Angulated Neck Based on Transient Hemodynamics Using an Idealized Model. APPLIED SCIENCES-BASEL 2022. [DOI: 10.3390/app12042113] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/10/2022]
Abstract
An abdominal aortic aneurysm (AAA) is an enlargement of the abdominal aorta that can become a life-threatening disease. The pulsatile blood flow exhibits intricate laminar patterns in the abdominal portion of the human aorta under normal resting conditions, whereas secondary flows are caused by adjacent branches and abnormal vessel geometries. If a pathological disorder (e.g., aneurysm) alters the structural composition of the artery wall, the flow dynamics become more complex. In this study, we analyzed the hemodynamics of pulsatile blood flow in three-dimensional AAA models. Computational predictions of hemodynamic changes were performed considering idealized models for four severe proximal neck angulations of symmetric aneurysms assuming conditions of laminar flow and a rigid artery wall. The predictions were based on computational fluid dynamics throughout the cardiac cycle. Postprocessing was used to visualize the numerical findings. The hemodynamic changes in factors such as velocity, flow streamline, pressure, and wall shear stress were obtained and visualized. The resulting blood flow through the severely angulated proximal neck of the abdominal aorta caused strong turbulence and asymmetric flow inside the aneurysm sac, leading to blood recirculation, especially during diastole. The simulation results showed the formation of regions with high and low wall shear stress, turbulent flow, and recirculation in the aneurysm sac depending on the angulation, which could have led to aortic wall weakness.
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9
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Inlet and Outlet Boundary Conditions and Uncertainty Quantification in Volumetric Lattice Boltzmann Method for Image-Based Computational Hemodynamics. FLUIDS 2022. [DOI: 10.3390/fluids7010030] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Inlet and outlet boundary conditions (BCs) play an important role in newly emerged image-based computational hemodynamics for blood flows in human arteries anatomically extracted from medical images. We developed physiological inlet and outlet BCs based on patients’ medical data and integrated them into the volumetric lattice Boltzmann method. The inlet BC is a pulsatile paraboloidal velocity profile, which fits the real arterial shape, constructed from the Doppler velocity waveform. The BC of each outlet is a pulsatile pressure calculated from the three-element Windkessel model, in which three physiological parameters are tuned by the corresponding Doppler velocity waveform. Both velocity and pressure BCs are introduced into the lattice Boltzmann equations through Guo’s non-equilibrium extrapolation scheme. Meanwhile, we performed uncertainty quantification for the impact of uncertainties on the computation results. An application study was conducted for six human aortorenal arterial systems. The computed pressure waveforms have good agreement with the medical measurement data. A systematic uncertainty quantification analysis demonstrates the reliability of the computed pressure with associated uncertainties in the Windkessel model. With the developed physiological BCs, the image-based computation hemodynamics is expected to provide a computation potential for the noninvasive evaluation of hemodynamic abnormalities in diseased human vessels.
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Fevola E, Ballarin F, Jiménez‐Juan L, Fremes S, Grivet‐Talocia S, Rozza G, Triverio P. An optimal control approach to determine resistance-type boundary conditions from in-vivo data for cardiovascular simulations. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2021; 37:e3516. [PMID: 34337877 PMCID: PMC9285750 DOI: 10.1002/cnm.3516] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/26/2021] [Accepted: 07/26/2021] [Indexed: 06/01/2023]
Abstract
The choice of appropriate boundary conditions is a fundamental step in computational fluid dynamics (CFD) simulations of the cardiovascular system. Boundary conditions, in fact, highly affect the computed pressure and flow rates, and consequently haemodynamic indicators such as wall shear stress (WSS), which are of clinical interest. Devising automated procedures for the selection of boundary conditions is vital to achieve repeatable simulations. However, the most common techniques do not automatically assimilate patient-specific data, relying instead on expensive and time-consuming manual tuning procedures. In this work, we propose a technique for the automated estimation of outlet boundary conditions based on optimal control. The values of resistive boundary conditions are set as control variables and optimized to match available patient-specific data. Experimental results on four aortic arches demonstrate that the proposed framework can assimilate 4D-Flow MRI data more accurately than two other common techniques based on Murray's law and Ohm's law.
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Affiliation(s)
- Elisa Fevola
- Department of Electronics and TelecommunicationsPolitecnico di TorinoTorinoItaly
| | - Francesco Ballarin
- MathLab, Mathematics areaSISSA ‐ International School for Advanced StudiesTriesteItaly
- Department of Mathematics and PhysicsCatholic University of the Sacred HeartBresciaItaly
| | - Laura Jiménez‐Juan
- Department of Medical ImagingSt Michael's Hospital and Sunnybrook Research Institute, University of TorontoTorontoCanada
| | - Stephen Fremes
- Schulich Heart CentreSunnybrook Health Sciences Center and Sunnybrook Research Institute, University of TorontoTorontoCanada
| | | | - Gianluigi Rozza
- MathLab, Mathematics areaSISSA ‐ International School for Advanced StudiesTriesteItaly
| | - Piero Triverio
- Department of Electrical & Computer EngineeringInstitute of Biomedical Engineering, University of TorontoTorontoCanada
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Bennati L, Vergara C, Domanin M, Malloggi C, Bissacco D, Trimarchi S, Silani V, Parati G, Casana R. A Computational Fluid-Structure Interaction Study for Carotids With Different Atherosclerotic Plaques. J Biomech Eng 2021; 143:091002. [PMID: 33876184 DOI: 10.1115/1.4050910] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2020] [Indexed: 11/08/2022]
Abstract
Atherosclerosis is a systemic disease that leads to accumulation of deposits, known as atherosclerotic plaques, within the walls of the carotids. In particular, three types of plaque can be distinguished: soft, fibrous, and calcific. Most of the computational studies who investigated the interplay between the plaque and the blood flow on patient-specific geometries used nonstandard medical images to directly delineate and segment the plaque and its components. However, these techniques are not so widely available in the clinical practice. In this context, the aim of our work was twofold: (i) to propose a new geometric tool that allowed to reconstruct a plausible plaque in the carotids from standard images and (ii) to perform three-dimensional (3D) fluid-structure interaction (FSI) simulations where we compared some fluid-dynamic and structural quantities among 15 patients characterized by different typologies of plaque. Our results highlighted that both the morphology and the mechanical properties of different plaque components play a crucial role in determining the vulnerability of the plaque.
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Affiliation(s)
- Lorenzo Bennati
- Department of Surgery, Dentistry, Paediatrics and Gynaecology, University of Verona, Verona 37129, Italy
| | - Christian Vergara
- LABS, Dipartimento di Chimica, Materiali e Ingegneria Chimica "Giulio Natta," Politecnico di Milano, Milan 20133, Italy
| | - Maurizio Domanin
- Vascular Surgery Unit, IRCCS, Ospedale Maggiore Policlinico, Milan 20133, Italy; Department of Clinical Sciences and Community Health, University of Milan, Milan 20133, Italy
| | - Chiara Malloggi
- Laboratory of Research in Vascular Surgery, Istituto Auxologico Italiano, IRCCS, Milan 20133, Italy
| | - Daniele Bissacco
- Vascular Surgery Unit, IRCCS, Ospedale Maggiore Policlinico, Milan 20133, Italy
| | - Santi Trimarchi
- Vascular Surgery Unit, IRCCS, Ospedale Maggiore Policlinico, Milan 20133, Italy; Department of Clinical Sciences and Community Health, University of Milan, Milan 20133, Italy
| | - Vincenzo Silani
- Department of Neurology-Stroke Unit and Laboratory of Neuroscience, Ospedale San Luca, Istituto Auxologico Italiano, IRCCS, Milan 20133, Italy; Department of Pathophysiology and Transplantation, University of Milan, Milan 20133, Italy
| | - Gianfranco Parati
- Department of Cardiovascular, Neural and Metabolic Sciences, Ospedale San Luca, Istituto Auxologico Italiano, IRCCS, Milan 20133, Italy; Department of Medicine and Surgery, Università di Milano-Bicocca, Monza 20900, Italy
| | - Renato Casana
- Laboratory of Research in Vascular Surgery, Istituto Auxologico Italiano, IRCCS, Milan 20133, Italy; Department of Surgery, Istituto Auxologico Italiano, IRCCS, Milan 20133, Italy
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12
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Antonuccio MN, Mariotti A, Fanni BM, Capellini K, Capelli C, Sauvage E, Celi S. Effects of Uncertainty of Outlet Boundary Conditions in a Patient-Specific Case of Aortic Coarctation. Ann Biomed Eng 2021; 49:3494-3507. [PMID: 34431017 PMCID: PMC8671284 DOI: 10.1007/s10439-021-02841-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2021] [Accepted: 07/20/2021] [Indexed: 12/22/2022]
Abstract
Computational Fluid Dynamics (CFD) simulations of blood flow are widely used to compute a variety of hemodynamic indicators such as velocity, time-varying wall shear stress, pressure drop, and energy losses. One of the major advances of this approach is that it is non-invasive. The accuracy of the cardiovascular simulations depends directly on the level of certainty on input parameters due to the modelling assumptions or computational settings. Physiologically suitable boundary conditions at the inlet and outlet of the computational domain are needed to perform a patient-specific CFD analysis. These conditions are often affected by uncertainties, whose impact can be quantified through a stochastic approach. A methodology based on a full propagation of the uncertainty from clinical data to model results is proposed here. It was possible to estimate the confidence associated with model predictions, differently than by deterministic simulations. We evaluated the effect of using three-element Windkessel models as the outflow boundary conditions of a patient-specific aortic coarctation model. A parameter was introduced to calibrate the resistances of the Windkessel model at the outlets. The generalized Polynomial Chaos method was adopted to perform the stochastic analysis, starting from a few deterministic simulations. Our results show that the uncertainty of the input parameter gave a remarkable variability on the volume flow rate waveform at the systolic peak simulating the conditions before the treatment. The same uncertain parameter had a slighter effect on other quantities of interest, such as the pressure gradient. Furthermore, the results highlight that the fine-tuning of Windkessel resistances is not necessary to simulate the post-stenting scenario.
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Affiliation(s)
- Maria Nicole Antonuccio
- BioCardioLab, Bioengineering Unit - Heart Hospital, Fondazione Toscana "G. Monasterio", Massa, Italy
| | - Alessandro Mariotti
- Civil and Industrial Engineering Department, University of Pisa, Pisa, Italy
| | - Benigno Marco Fanni
- BioCardioLab, Bioengineering Unit - Heart Hospital, Fondazione Toscana "G. Monasterio", Massa, Italy
- Information Engineering Department, University of Pisa, Pisa, Italy
| | - Katia Capellini
- BioCardioLab, Bioengineering Unit - Heart Hospital, Fondazione Toscana "G. Monasterio", Massa, Italy
- Information Engineering Department, University of Pisa, Pisa, Italy
| | - Claudio Capelli
- Institute of Cardiovascular Science, University College of London, London, UK
| | - Emilie Sauvage
- Institute of Cardiovascular Science, University College of London, London, UK
| | - Simona Celi
- BioCardioLab, Bioengineering Unit - Heart Hospital, Fondazione Toscana "G. Monasterio", Massa, Italy.
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13
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Johnston L, Allen R, Hall Barrientos P, Mason A, Kazakidi A. Hemodynamic Abnormalities in the Aorta of Turner Syndrome Girls. Front Cardiovasc Med 2021; 8:670841. [PMID: 34141729 PMCID: PMC8203817 DOI: 10.3389/fcvm.2021.670841] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2021] [Accepted: 05/06/2021] [Indexed: 01/15/2023] Open
Abstract
Congenital abnormalities in girls and women with Turner syndrome (TS), alongside an underlying predisposition to obesity and hypertension, contribute to an increased risk of cardiovascular disease and ultimately reduced life expectancy. We observe that children with TS present a greater variance in aortic arch morphology than their healthy counterparts, and hypothesize that their hemodynamics is also different. In this study, computational fluid dynamic (CFD) simulations were performed for four TS girls, and three age-matched healthy girls, using patient-specific inlet boundary conditions, obtained from phase-contrast MRI data. The visualization of multidirectional blood flow revealed an increase in vortical flow in the arch, supra-aortic vessels, and descending aorta, and a correlation between the presence of aortic abnormalities and disturbed flow. Compared to the relatively homogeneous pattern of time-averaged wall shear stress (TAWSS) on the healthy aortae, a highly heterogeneous distribution with elevated TAWSS values was observed in the TS geometries. Visualization of further shear stress parameters, such as oscillatory shear index (OSI), normalized relative residence time (RRTn), and transverse WSS (transWSS), revealed dissimilar heterogeneity in the oscillatory and multidirectional nature of the aortic flow. Taking into account the young age of our TS cohort (average age 13 ± 2 years) and their obesity level (75% were obese or overweight), which is believed to accelerate the initiation and progression of endothelial dysfunction, these findings may be an indication of atherosclerotic disease manifesting earlier in life in TS patients. Age, obesity and aortic morphology may, therefore, play a key role in assessing cardiovascular risk in TS children.
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Affiliation(s)
- Lauren Johnston
- Department of Biomedical Engineering, University of Strathclyde, Glasgow, United Kingdom
| | - Ruth Allen
- Department of Radiology, Royal Hospital for Children, Glasgow, United Kingdom
| | | | - Avril Mason
- Department of Paediatric Endocrinology, Royal Hospital for Children, Queen Elizabeth University Hospital, Glasgow, United Kingdom
| | - Asimina Kazakidi
- Department of Biomedical Engineering, University of Strathclyde, Glasgow, United Kingdom
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Pozzi S, Domanin M, Forzenigo L, Votta E, Zunino P, Redaelli A, Vergara C. A surrogate model for plaque modeling in carotids based on Robin conditions calibrated by cine MRI data. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2021; 37:e3447. [PMID: 33586336 DOI: 10.1002/cnm.3447] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Revised: 12/05/2020] [Accepted: 12/07/2020] [Indexed: 06/12/2023]
Abstract
We propose a surrogate model for the fluid-structure interaction (FSI) problem for the study of blood dynamics in carotid arteries in presence of plaque. This is based on the integration of a numerical model with subject-specific data and clinical imaging. We propose to model the plaque as part of the tissues surrounding the vessel wall through the application of an elastic support boundary condition. In order to characterize the plaque and other surrounding tissues, such as the close-by jugular vein, the elastic parameters of the boundary condition were spatially differentiated and their values were estimated by minimizing the discrepancies between computed vessel displacements and reference values obtained from CINE Magnetic Resonance Imaging data. We applied the model to three subjects with a degree of stenosis greater than 70%. We found that accounting for both plaque and jugular vein in the estimation of the elastic parameters increases the accuracy. In particular, in all patients, mismatches between computed and in vivo measured wall displacements were one to two orders of magnitude lower than the spatial resolution of the original MRI data. These results confirmed the validity of the proposed surrogate plaque model. We also compared fluid-dynamics results with those obtained in a fixed wall setting and in a full FSI model, used as gold standard, highlighting the better accordance of our results in comparison to the rigid ones.
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Affiliation(s)
- Silvia Pozzi
- MOX, Department of Mathematics, Politecnico di Milano, Milan, 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
| | - Laura Forzenigo
- Unità Operativa di Radiologia, Fondazione I.R.C.C.S. Cà Granda, Ospedale Maggiore Policlinico, Milan, Italy
| | - Emiliano Votta
- Dipartimento di Elettronica, Informazione e Bioingegneria, Politecnico di Milano, Milan, Italy
| | - Paolo Zunino
- MOX, Department of Mathematics, Politecnico di Milano, Milan, Italy
| | - Alberto Redaelli
- Dipartimento di Elettronica, Informazione e Bioingegneria, Politecnico di Milano, Milan, Italy
| | - Christian Vergara
- LaBS, Dipartimento di Chimica, Materiali e Ingegneria Chimica "Giulio Natta", Politecnico di Milano, Milan, Italy
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15
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Vardhan M, Randles A. Application of physics-based flow models in cardiovascular medicine: Current practices and challenges. BIOPHYSICS REVIEWS 2021; 2:011302. [PMID: 38505399 PMCID: PMC10903374 DOI: 10.1063/5.0040315] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/11/2020] [Accepted: 02/18/2021] [Indexed: 03/21/2024]
Abstract
Personalized physics-based flow models are becoming increasingly important in cardiovascular medicine. They are a powerful complement to traditional methods of clinical decision-making and offer a wealth of physiological information beyond conventional anatomic viewing using medical imaging data. These models have been used to identify key hemodynamic biomarkers, such as pressure gradient and wall shear stress, which are associated with determining the functional severity of cardiovascular diseases. Importantly, simulation-driven diagnostics can help researchers understand the complex interplay between geometric and fluid dynamic parameters, which can ultimately improve patient outcomes and treatment planning. The possibility to compute and predict diagnostic variables and hemodynamics biomarkers can therefore play a pivotal role in reducing adverse treatment outcomes and accelerate development of novel strategies for cardiovascular disease management.
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Affiliation(s)
- M. Vardhan
- Department of Biomedical Engineering, Duke University, Durham, North Carolina 27708, USA
| | - A. Randles
- Department of Biomedical Engineering, Duke University, Durham, North Carolina 27708, USA
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16
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Riva A, Sturla F, Caimi A, Pica S, Giese D, Milani P, Palladini G, Lombardi M, Redaelli A, Votta E. 4D flow evaluation of blood non-Newtonian behavior in left ventricle flow analysis. J Biomech 2021; 119:110308. [PMID: 33631666 DOI: 10.1016/j.jbiomech.2021.110308] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2021] [Accepted: 02/03/2021] [Indexed: 12/31/2022]
Abstract
Blood is generally modeled as a Newtonian fluid, assuming a standard and constant viscosity; however, this assumption may not hold for the highly pulsatile and recirculating intracavitary flow in the left ventricle (LV), hampering the quantification of fluid dynamic indices of potential clinical relevance. Herein, we investigated the effect of three viscosity models on the patient-specific quantification of LV blood energetics, namely on viscous energy loss (EL), from 4D Flow magnetic resonance imaging: I) Newtonian with standard viscosity (3.7 cP), II) Newtonian with subject-specific hematocrit-dependent viscosity, III) non-Newtonian accounting for the effect of hematocrit and shear rate. Analyses were performed on 5 controls and 5 patients with cardiac light-chain amyloidosis. In Model II, viscosity ranged between 3.0 (-19%) and 4.3 cP (+16%), mildly deviating from the standard value. In the non-Newtonian model, this effect was emphasized: viscosity ranged from 3.2 to 6.0 cP, deviating maximally from the standard value in low shear rate (i.e., <100 s-1) regions. This effect reflected on EL quantifications: in particular, as compared to Model I, Model III yielded markedly higher EL values (up to +40%) or markedly lower (down to -21%) for subjects with hematocrit higher than 39.5% and lower than 30%, respectively. Accounting for non-Newtonian blood behavior on a patient-specific basis may enhance the accuracy of intracardiac energetics assessment by 4D Flow, which may be explored as non-invasive index to discriminate between healthy and pathologic LV.
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Affiliation(s)
- Alessandra Riva
- Department of Electronics, Information and Bioengineering, Politecnico di Milano, Milan, Italy; 3D and Computer Simulation Laboratory, IRCCS Policlinico San Donato, San Donato Milanese, Italy
| | - Francesco Sturla
- 3D and Computer Simulation Laboratory, IRCCS Policlinico San Donato, San Donato Milanese, Italy; Department of Electronics, Information and Bioengineering, Politecnico di Milano, Milan, Italy.
| | - Alessandro Caimi
- Department of Electronics, Information and Bioengineering, Politecnico di Milano, Milan, Italy
| | - Silvia Pica
- Multimodality Cardiac Imaging Section, IRCCS Policlinico San Donato, San Donato Milanese, Italy
| | | | - Paolo Milani
- Amyloidosis Research and Treatment Center, Fondazione IRCCS Policlinico San Matteo and University of Pavia, Pavia, Italy
| | - Giovanni Palladini
- Amyloidosis Research and Treatment Center, Fondazione IRCCS Policlinico San Matteo and University of Pavia, Pavia, Italy
| | - Massimo Lombardi
- Multimodality Cardiac Imaging Section, IRCCS Policlinico San Donato, San Donato Milanese, Italy
| | - Alberto Redaelli
- Department of Electronics, Information and Bioengineering, Politecnico di Milano, Milan, Italy
| | - Emiliano Votta
- Department of Electronics, Information and Bioengineering, Politecnico di Milano, Milan, Italy; 3D and Computer Simulation Laboratory, IRCCS Policlinico San Donato, San Donato Milanese, Italy
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17
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Redaelli A, Votta E. Cardiovascular patient-specific modeling: Where are we now and what does the future look like? APL Bioeng 2020; 4:040401. [PMID: 33195957 DOI: 10.1063/5.0031452] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Accepted: 10/23/2020] [Indexed: 12/15/2022] Open
Affiliation(s)
- Alberto Redaelli
- Department of Electronics, Information and Bioengineering, Politecnico di Milano, Milan, Italy
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18
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Sun P, Bozkurt S, Sorguven E. Computational analyses of aortic blood flow under varying speed CF-LVAD support. Comput Biol Med 2020; 127:104058. [PMID: 33091606 DOI: 10.1016/j.compbiomed.2020.104058] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Revised: 09/21/2020] [Accepted: 10/11/2020] [Indexed: 11/17/2022]
Abstract
Continuous Flow Left Ventricular Assist Devices (CF-LVADs) generally operate at a constant speed whilst supporting a failing heart. However, constant speed CF-LVAD support may cause complications and increase the morbidity rates in the patients. Therefore, different varying speed operating modes for CF-LVADs have been proposed to generate more physiological blood flow, which may reduce complication rates under constant speed CF-LVAD support. The proposed varying speed CF-LVAD algorithms simulate time-dependant dynamics and three dimensional blood flow patterns in aorta under varying speed CF-LVAD support remain unclear. The aim of this study is to evaluate three dimensional blood flow patterns in a patient-specific aorta model under co-pulsating and counter-pulsating CF-LVAD support modes driven by speed and flow rate control algorithms using numerical simulations. Aortic blood flow was evaluated for 10,000 rpm constant speed CF-LVAD support generating 4.71 L/min mean flow rate over a cardiac cycle. Co-pulsating and counter-pulsating CF-LVAD speed control operated the pump at the same average speed over a cardiac cycle and co-pulsating and counter-pulsating CF-LVAD flow rate control generated the same average flow rate over cardiac cycle as in the constant speed pump support. Simulation results show that the utilised counter-pulsating pump flow rate control may decrease the haemolysis to a third compared to the most commonly employed constant speed pump operating mode. Moreover, CF-LVAD support utilising counter-pulsating pump flow rate control generated the most favourable hemodynamic characteristics, i.e. low Dean number, least wall shear stress and least haemolysis values among the investigated cases.
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Affiliation(s)
- Peiying Sun
- Thermo Fluid Mechanics Research Centre (TFMRC), University of Sussex, Falmer, BN1 9RS, UK
| | - Selim Bozkurt
- Institute of Cardiovascular Science, University College London, London, WC1E 6BT, UK
| | - Esra Sorguven
- Thermo Fluid Mechanics Research Centre (TFMRC), University of Sussex, Falmer, BN1 9RS, UK.
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19
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Blood flow simulations in patient-specific geometries of the carotid artery: A systematic review. J Biomech 2020; 111:110019. [PMID: 32905972 DOI: 10.1016/j.jbiomech.2020.110019] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2020] [Revised: 08/07/2020] [Accepted: 08/26/2020] [Indexed: 12/21/2022]
Abstract
Computational Fluid Dynamics (CFD) and Fluid-Structure Interaction (FSI) are currently widely applied in the study of blood flow parameters and their alterations under pathological conditions, which are important indicators for diagnosis of atherosclerosis. In this manuscript, a systematic review of the published literature was conducted, according to the guidelines of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses, on the simulation studies of blood flow in patient-specific geometries of the carotid artery bifurcation. Scopus, PubMed and ScienceDirect databases were used in the literature search, which was completed on the 3rd of August 2020. Forty-nine articles were included after the selection process and were organized in two distinct categories: the CFD studies (36/49 articles), which comprise only the fluid analysis and the FSI studies (13/49 articles), which includes both fluid and Fluid-Structure domain in the analysis. The data of the research works was structured in different categories (Geometry, Viscosity models, Type of Flow, Boundary Conditions, Flow Parameters, Type of Solver and Validation). The aim of this systematic review is to demonstrate the methodology in the modelling, simulation and analysis of carotid blood flow and also identify potential gaps and challenges in this research field.
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20
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Swanson L, Owen B, Keshmiri A, Deyranlou A, Aldersley T, Lawrenson J, Human P, De Decker R, Fourie B, Comitis G, Engel ME, Keavney B, Zühlke L, Ngoepe M, Revell A. A Patient-Specific CFD Pipeline Using Doppler Echocardiography for Application in Coarctation of the Aorta in a Limited Resource Clinical Context. Front Bioeng Biotechnol 2020; 8:409. [PMID: 32582648 PMCID: PMC7283385 DOI: 10.3389/fbioe.2020.00409] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Accepted: 04/14/2020] [Indexed: 12/14/2022] Open
Abstract
Congenital heart disease (CHD) is the most common birth defect globally and coarctation of the aorta (CoA) is one of the commoner CHD conditions, affecting around 1/1800 live births. CoA is considered a CHD of critical severity. Unfortunately, the prognosis for a child born in a low and lower-middle income country (LLMICs) with CoA is far worse than in a high-income country. Reduced diagnostic and interventional capacities of specialists in these regions lead to delayed diagnosis and treatment, which in turn lead to more cases presenting at an advanced stage. Computational fluid dynamics (CFD) is an important tool in this context since it can provide additional diagnostic data in the form of hemodynamic parameters. It also provides an in silico framework, both to test potential procedures and to assess the risk of further complications arising post-repair. Although this concept is already in practice in high income countries, the clinical infrastructure in LLMICs can be sparse, and access to advanced imaging modalities such as phase contrast magnetic resonance imaging (PC-MRI) is limited, if not impossible. In this study, a pipeline was developed in conjunction with clinicians at the Red Cross War Memorial Children’s Hospital, Cape Town and was applied to perform a patient-specific CFD study of CoA. The pipeline uses data acquired from CT angiography and Doppler transthoracic echocardiography (both much more clinically available than MRI in LLMICs), while segmentation is conducted via SimVascular and simulation is realized using OpenFOAM. The reduction in cost through use of open-source software and the use of broadly available imaging modalities makes the methodology clinically feasible and repeatable within resource-constrained environments. The project identifies the key role of Doppler echocardiography, despite its disadvantages, as an intrinsic component of the pipeline if it is to be used routinely in LLMICs.
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Affiliation(s)
- Liam Swanson
- Department of Mechanical Engineering, University of Cape Town, Cape Town, South Africa
| | - Benjamin Owen
- Department of Mechanical, Aerospace and Civil Engineering (MACE), The University of Manchester, Manchester, United Kingdom
| | - Amir Keshmiri
- Department of Mechanical, Aerospace and Civil Engineering (MACE), The University of Manchester, Manchester, United Kingdom
| | - Amin Deyranlou
- Department of Mechanical, Aerospace and Civil Engineering (MACE), The University of Manchester, Manchester, United Kingdom
| | - Thomas Aldersley
- Department of Paediatrics and Child Health, University of Cape Town, Cape Town, South Africa
| | - John Lawrenson
- Department of Paediatrics and Child Health, Tygerberg Hospital, Stellenbosch University and Tygerberg Hospital, Cape Town, South Africa
| | - Paul Human
- Christiaan Barnard Division of Cardiothoracic Surgery, University of Cape Town and Groote Schuur Hospital, Cape Town, South Africa
| | - Rik De Decker
- Department of Paediatrics and Child Health, University of Cape Town, Cape Town, South Africa
| | - Barend Fourie
- Department of Paediatrics and Child Health, Tygerberg Hospital, Stellenbosch University and Tygerberg Hospital, Cape Town, South Africa
| | - George Comitis
- Department of Paediatrics and Child Health, University of Cape Town, Cape Town, South Africa
| | - Mark E Engel
- Department of Medicine, University of Cape Town, Cape Town, South Africa
| | - Bernard Keavney
- Division of Cardiovascular Sciences, Faculty of Biology, Medicine and Health, School of Medical Sciences, The University of Manchester, Manchester, United Kingdom.,Manchester University NHS Foundation Trust, Manchester Academic Health Science Centre, Manchester, United Kingdom
| | - Liesl Zühlke
- Department of Paediatrics and Child Health, University of Cape Town, Cape Town, South Africa
| | - Malebogo Ngoepe
- Department of Mechanical Engineering, University of Cape Town, Cape Town, South Africa
| | - Alistair Revell
- Department of Mechanical, Aerospace and Civil Engineering (MACE), The University of Manchester, Manchester, United Kingdom
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Töger J, Zahr MJ, Aristokleous N, Markenroth Bloch K, Carlsson M, Persson P. Blood flow imaging by optimal matching of computational fluid dynamics to 4D‐flow data. Magn Reson Med 2020; 84:2231-2245. [DOI: 10.1002/mrm.28269] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2020] [Revised: 02/21/2020] [Accepted: 03/09/2020] [Indexed: 01/08/2023]
Affiliation(s)
- Johannes Töger
- Department of Clinical Sciences Lund Diagnostic Radiology Lund UniversitySkåne University Hospital Lund Sweden
- Department of Clinical Sciences Lund Clinical Physiology Lund UniversitySkåne University Hospital Lund Sweden
| | - Matthew J. Zahr
- Mathematics Group Lawrence Berkeley National Laboratory Berkeley CA
- Department of Aerospace and Mechanical Engineering University of Notre Dame Notre Dame IN
| | - Nicolas Aristokleous
- Department of Clinical Sciences Lund Clinical Physiology Lund UniversitySkåne University Hospital Lund Sweden
| | | | - Marcus Carlsson
- Department of Clinical Sciences Lund Clinical Physiology Lund UniversitySkåne University Hospital Lund Sweden
| | - Per‐Olof Persson
- Mathematics Group Lawrence Berkeley National Laboratory Berkeley CA
- Department of Mathematics University of California Berkeley CA
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22
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Debbich A, Ben Abdallah A, Maatouk M, Hmida B, Sigovan M, Clarysse P, Bedoui MH. A Spatiotemporal exploration and 3D modeling of blood flow in healthy carotid artery bifurcation from two modalities: Ultrasound-Doppler and phase contrast MRI. Comput Biol Med 2020; 118:103644. [DOI: 10.1016/j.compbiomed.2020.103644] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2019] [Revised: 01/31/2020] [Accepted: 02/03/2020] [Indexed: 10/25/2022]
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Bit A, Alblawi A, Chattopadhyay H, Quais QA, Benim AC, Rahimi-Gorji M, Do HT. Three dimensional numerical analysis of hemodynamic of stenosed artery considering realistic outlet boundary conditions. COMPUTER METHODS AND PROGRAMS IN BIOMEDICINE 2020; 185:105163. [PMID: 31710989 DOI: 10.1016/j.cmpb.2019.105163] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/25/2019] [Revised: 10/25/2019] [Accepted: 10/29/2019] [Indexed: 06/10/2023]
Abstract
BACKGROUND AND OBJECTIVE Mortality rate increases globally among which one third is due to diseased blood vessels. Due to late diagnoses of the disease in vessels (severe stenoses), qualitative and rapid assessment becomes difficult. Earlier assessment of stenoses can lead to formulation of effective treatment protocol. It is often found that proliferation of secondary stenoses at downstream of a stenosed vessel depends on the degree of severity of primary stenoses. Numerical investigation of flow dynamics of blood in such condition helps in prediction of distributed field of secondarystenoses. This investigation also requires consideration of rigorous boundary conditions at inlet and outlet of defined flow domain. METHODS Patient-specific geometry of aortic arch with stenoses in descending aorta was considered for numerical estimation of biofluid dynamics. Boundary conditionsat inlet and outlet were extracted from time-resolved pulsed Doppler Ultrasound imaging at appropriate sections of the vessel. Womersley inlet flux was considered. Flow parameters like wall shear stress, oscillatory shear index, etc. were evaluated at upper and lower aortic arch of the vessel at different combinations of boundary conditions at inlet and four outlets respectively. RESULTS Effect of outlet boundary conditions were acknowledged for the progression of secondary stenoses. Severity of primary stenoses was found influencing the progression of secondary stenoses. It was found that the outlets Left Subclavian Artery and Left Common Carotid Artery greatly influence the flow dynamic structure within the stenosed aortic arch. Simultaneously, lower wall of aortic-arch had shown more affinity for secondary stenoses progression. CONCLUSION Aortic arch is a vital anatomical region of circulatory system which is vulnerable to progression of secondary stenoses in presence of primary stenoses in ascending or descending aorta. It also drives the author to speculate the influence of anurysm in descending aorta on this landmark of aortic arch.
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Affiliation(s)
- Arindam Bit
- Department of Biomedical Engineering, National Institute of Technology, Raipur, India.
| | - Adel Alblawi
- Mechanical Engineering Department, College of Engineering, Shaqra University, Dawadmi P.O. 11911, Ar Riyadh, Saudi Arabia.
| | | | - Qurratul Ain Quais
- Department of Biomedical Engineering, National Institute of Technology, Raipur, India
| | - Ali Cemal Benim
- Faculty of Mechanical and Process Engineering, Duesseldorf University of Applied Sciences, Germany
| | - Mohammad Rahimi-Gorji
- Experimental Surgery Lab, Faculty of Medicine and Health Science, Ghent University, Ghent 9000, Belgium; Biofluid, Tissue and Solid Mechanics for Medical Applications Lab (IBiTech- bioMMeda), Ghent University, Ghent, Belgium.
| | - Hoang-Thinh Do
- Division of Computational Mechatronics, Institute for Computational Science, Ton Duc Thang University, Ho Chi Minh City, Vietnam; Faculty of Electrical & Electronics Engineering, Ton Duc Thang University, Ho Chi Minh City, Vietnam.
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Mendieta JB, Fontanarosa D, Wang J, Paritala PK, McGahan T, Lloyd T, Li Z. The importance of blood rheology in patient-specific computational fluid dynamics simulation of stenotic carotid arteries. Biomech Model Mechanobiol 2020; 19:1477-1490. [DOI: 10.1007/s10237-019-01282-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2019] [Accepted: 12/17/2019] [Indexed: 12/15/2022]
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Computational study on hemodynamic changes in patient-specific proximal neck angulation of abdominal aortic aneurysm with time-varying velocity. AUSTRALASIAN PHYSICAL & ENGINEERING SCIENCES IN MEDICINE 2019; 42:181-190. [PMID: 30762222 DOI: 10.1007/s13246-019-00728-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/10/2018] [Accepted: 01/21/2019] [Indexed: 12/27/2022]
Abstract
Aneurysms are considered as a critical cardiovascular disease worldwide when they rupture. The clinical understanding of geometrical impact on the flow behaviour and biomechanics of abdominal aortic aneurysm (AAA) is progressively developing. Proximal neck angulations of AAAs are believed to influence the hemodynamic changes and wall shear stress (WSS) within AAAs. Our aim was to perform pulsatile simulations using computational fluid dynamics (CFD) for patient-specific geometry to investigate the influence of severe angular (≥ 60°) neck on AAA's hemodynamic and wall shear stress. The patient's geometrical characteristics were obtained from a computed tomography images database of AAA patients. The AAA geometry was reconstructed using Mimics software. In computational method, blood was assumed Newtonian fluid and an inlet varying velocity waveform in a cardiac cycle was assigned. The CFD study was performed with ANSYS software. The results of flow behaviours indicated that the blood flow through severe bending of angular neck leads to high turbulence and asymmetry of flows within the aneurysm sac resulting in blood recirculation. The high wall shear stress (WSS) occurred near the AAA neck and on surface of aneurysm sac. This study explained and showed flow behaviours and WSS progression within high angular neck AAA and risk prediction of abdominal aorta rupture. We expect that the visualization of blood flow and hemodynamic changes resulted from CFD simulation could be as an extra tool to assist clinicians during a decision making when estimation the risks of interventional procedures.
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Aristokleous N, Houston JG, Browne LD, Broderick SP, Kokkalis E, Gandy SJ, Walsh MT. Morphological and hemodynamical alterations in brachial artery and cephalic vein. An image-based study for preoperative assessment for vascular access creation. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2018; 34:e3136. [PMID: 30070048 DOI: 10.1002/cnm.3136] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/23/2018] [Revised: 06/04/2018] [Accepted: 07/15/2018] [Indexed: 06/08/2023]
Abstract
The current study aims to computationally evaluate the effect of right upper arm position on the geometric and hemodynamic characteristics of the brachial artery (BA) and cephalic vein (CV) and, furthermore, to present in detail the methodology to characterise morphological and hemodynamical healthy vessels. Ten healthy volunteers were analysed in two configurations, the supine (S) and the prone (P) position. Lumen 3D surface models were constructed from images acquired from a non-contrast MRI sequence. Then, the models were used to numerically compute the physiological range of geometric (n = 10) and hemodynamic (n = 3) parameters in the BA and CV. Geometric parameters such as curvature and tortuosity, and hemodynamic parameters based on wall shear stress (WSS) metrics were calculated with the use of computational fluid dynamics. Our results highlight that changes in arm position had a greater impact on WSS metrics of the BA by altering the mean and maximum blood flow rate of the vessel. Whereas, curvature and tortuosity were found not to be significantly different between positions. Inter-variability was associated with antegrade and retrograde flow in BA, and antegrade flow in CV. Shear stress was low and oscillatory shear forces were negligible. This data suggests that deviations from this state may contribute to the risk of accelerated intimal hyperplasia of the vein in arteriovenous fistulas. Therefore, preoperative conditions coupled with post-operative longitudinal data will aid the identification of such relationships.
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Affiliation(s)
- Nicolas Aristokleous
- Bio-Science and Bio-Engineering Research (BioSciBER), School of Engineering, Bernal Institute and the Health Research Institute, University of Limerick, Castletroy, Limerick, Ireland
| | - J Graeme Houston
- Department of Cardiovascular and Diabetes Medicine, Ninewells Hospital and Medical School, University of Dundee, Dundee, UK
- NHS Tayside Clinical Radiology, Ninewells Hospital, Dundee, UK
| | - Leonard D Browne
- Bio-Science and Bio-Engineering Research (BioSciBER), School of Engineering, Bernal Institute and the Health Research Institute, University of Limerick, Castletroy, Limerick, Ireland
| | - Stephen P Broderick
- Bio-Science and Bio-Engineering Research (BioSciBER), School of Engineering, Bernal Institute and the Health Research Institute, University of Limerick, Castletroy, Limerick, Ireland
| | - Efstratios Kokkalis
- Department of Cardiovascular and Diabetes Medicine, Ninewells Hospital and Medical School, University of Dundee, Dundee, UK
| | | | - Michael T Walsh
- Bio-Science and Bio-Engineering Research (BioSciBER), School of Engineering, Bernal Institute and the Health Research Institute, University of Limerick, Castletroy, Limerick, Ireland
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Campobasso R, Condemi F, Viallon M, Croisille P, Campisi S, Avril S. Evaluation of Peak Wall Stress in an Ascending Thoracic Aortic Aneurysm Using FSI Simulations: Effects of Aortic Stiffness and Peripheral Resistance. Cardiovasc Eng Technol 2018; 9:707-722. [DOI: 10.1007/s13239-018-00385-z] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/17/2018] [Accepted: 10/08/2018] [Indexed: 12/25/2022]
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Pinto SIS, Campos JBLM, Azevedo E, Castro CF, Sousa LC. Numerical study on the hemodynamics of patient-specific carotid bifurcation using a new mesh approach. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2018; 34:e2972. [PMID: 29470857 DOI: 10.1002/cnm.2972] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/25/2017] [Revised: 02/02/2018] [Accepted: 02/14/2018] [Indexed: 06/08/2023]
Abstract
The definition of a suitable mesh to simulate blood flow in the human carotid bifurcation has been investigated. In this research, a novel mesh generation method is proposed: hexahedral cells at the center of the vessel and a fine grid of tetrahedral cells near the artery wall, in order to correctly simulate the large blood velocity gradients associated with specific locations. The selected numerical examples to show the pertinence of the novel generation method are supported by carotid ultrasound image data of a patient-specific case. Doppler systolic blood velocities measured during ultrasound examination are compared with simulated velocities using 4 different combinations of hexahedral and tetrahedral meshes and different fluid dynamic simulators. The Lin's test was applied to show the concordance of the results. Wall shear stress-based descriptors and localized normalized helicity descriptor emphasize the performance of the new method. Another feature is the reduced computation time required by the developed methodology. With the accurate combined mesh, different flow rate partitions, between the internal carotid artery and external carotid artery, were studied. The overall effect of the partitions is mainly in the blood flow patterns and in the hot-spot modulation of atherosclerosis-susceptible regions, rather than in their distribution along the bifurcation.
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Affiliation(s)
- S I S Pinto
- Transport Phenomena Research Center (CEFT), Engineering Faculty, University of Porto, Rua Dr. Roberto Frias, s/n, 4200 - 465, Porto, Portugal
| | - J B L M Campos
- Transport Phenomena Research Center (CEFT), Engineering Faculty, University of Porto, Rua Dr. Roberto Frias, s/n, 4200 - 465, Porto, Portugal
| | - E Azevedo
- Department of Neurology, São João Hospital Centre, Alameda Prof. Hernâni Monteiro, 4200 - 319, Porto, Portugal
- Department of Clinical Neurosciences and Mental Health, Faculty of Medicine, University of Porto, Alameda Prof. Hernâni Monteiro, 4200 - 319, Porto, Portugal
| | - C F Castro
- Institute of Science and Innovation in Mechanical and Industrial Engineering (INEGI), Engineering Faculty, University of Porto, Rua Dr. Roberto Frias, s/n, 4200 - 465, Porto, Portugal
| | - L C Sousa
- Institute of Science and Innovation in Mechanical and Industrial Engineering (INEGI), Engineering Faculty, University of Porto, Rua Dr. Roberto Frias, s/n, 4200 - 465, Porto, Portugal
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van de Velde L, Donselaar EJ, Groot Jebbink E, Boersen JT, Lajoinie GP, de Vries JPP, Zeebregts CJ, Versluis M, Reijnen MM. Partial renal coverage in endovascular aneurysm repair causes unfavorable renal flow patterns in an infrarenal aneurysm model. J Vasc Surg 2018; 67:1585-1594. [DOI: https:/doi.org/10.1016/j.jvs.2017.05.092] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2023]
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Partial renal coverage in endovascular aneurysm repair causes unfavorable renal flow patterns in an infrarenal aneurysm model. J Vasc Surg 2017; 67:1585-1594. [PMID: 28893490 DOI: 10.1016/j.jvs.2017.05.092] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2017] [Accepted: 05/01/2017] [Indexed: 11/23/2022]
Abstract
OBJECTIVE To achieve an optimal sealing zone during endovascular aneurysm repair, the intended positioning of the proximal end of the endograft fabric should be as close as possible to the most caudal edge of the renal arteries. Some endografts exhibit a small offset between the radiopaque markers and the proximal fabric edge. Unintended partial renal artery coverage may thus occur. This study investigated the consequences of partial coverage on renal flow patterns and wall shear stress (WSS). METHODS In vitro models of an abdominal aortic aneurysm were used to visualize pulsatile flow using two-dimensional particle image velocimetry under physiologic resting conditions. One model served as control and two models were stented with an Endurant endograft (Medtronic Inc, Minneapolis, Minn), one without and one with partial renal artery coverage with 1.3 mm of stent fabric extending beyond the marker (16% area coverage). The magnitude and oscillation of WSS, relative residence time, and backflow in the renal artery were analyzed. RESULTS In both stented models, a region along the caudal renal artery wall presented with low and oscillating WSS, not present in the control model. A region with very low WSS (<0.1 Pa) was present in the model with partial coverage over a length of 7 mm compared with a length of 2 mm in the model without renal coverage. Average renal backflow area percentage in the renal artery incrementally increased from control (0.9%) to the stented model without (6.4%) and with renal coverage (18.8%). CONCLUSIONS In this flow model, partial renal coverage after endovascular aneurysm repair causes low and marked oscillations in WSS, potentially promoting atherosclerosis and subsequent renal artery stenosis. Awareness of the device-dependent offset between the fabric edge and the radiopaque markers is therefore important in endovascular practice.
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Pirola S, Cheng Z, Jarral OA, O'Regan DP, Pepper JR, Athanasiou T, Xu XY. On the choice of outlet boundary conditions for patient-specific analysis of aortic flow using computational fluid dynamics. J Biomech 2017; 60:15-21. [PMID: 28673664 DOI: 10.1016/j.jbiomech.2017.06.005] [Citation(s) in RCA: 80] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2017] [Revised: 06/01/2017] [Accepted: 06/05/2017] [Indexed: 10/19/2022]
Abstract
Boundary conditions (BCs) are an essential part in computational fluid dynamics (CFD) simulations of blood flow in large arteries. Although several studies have investigated the influence of BCs on predicted flow patterns and hemodynamic wall parameters in various arterial models, there is a lack of comprehensive assessment of outlet BCs for patient-specific analysis of aortic flow. In this study, five different sets of outlet BCs were tested and compared using a subject-specific model of a normal aorta. Phase-contrast magnetic resonance imaging (PC-MRI) was performed on the same subject and velocity profiles extracted from the in vivo measurements were used as the inlet boundary condition. Computational results obtained with different outlet BCs were assessed in terms of their agreement with the PC-MRI velocity data and key hemodynamic parameters, such as pressure and flow waveforms and wall shear stress related indices. Our results showed that the best overall performance was achieved by using a well-tuned three-element Windkessel model at all model outlets, which not only gave a good agreement with in vivo flow data, but also produced physiological pressure waveforms and values. On the other hand, opening outlet BCs with zero pressure at multiple outlets failed to reproduce any physiologically relevant flow and pressure features.
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Affiliation(s)
- S Pirola
- Department of Chemical Engineering, Imperial College London, South Kensington Campus, London SW7 2AZ, UK
| | - Z Cheng
- Department of Chemical Engineering, Imperial College London, South Kensington Campus, London SW7 2AZ, UK
| | - O A Jarral
- Department of Surgery and Cancer, St. Mary's Hospital, Imperial College London, UK
| | - D P O'Regan
- MRC London Institute of Medical Sciences, Hammersmith Hospital, Imperial College London, UK
| | - J R Pepper
- Royal Brompton and Harefield NHS Foundation Trust, Sydney Street, London SW3 6NP, UK
| | - T Athanasiou
- Department of Surgery and Cancer, St. Mary's Hospital, Imperial College London, UK
| | - X Y Xu
- Department of Chemical Engineering, Imperial College London, South Kensington Campus, London SW7 2AZ, UK.
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Impact of Using Conventional Inlet/Outlet Boundary Conditions on Haemodynamic Metrics in a Subject-Specific Rabbit Aorta. Proc Inst Mech Eng H 2017; 232:103-113. [DOI: 10.1177/0954411917699237] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Computational fluid dynamics is a tool capable of accurately measuring metrics currently used to predict the behaviour of cardiovascular diseases. This study quantifies the impact various commonly used inlet and outlet boundary conditions have on various shear rate–based haemodynamic metrics currently used for predicting the localisation of cardiovascular diseases. Simulations are conducted on an accurately represented rabbit aorta configuration and comparison has been made against available in vivo data. The boundary conditions studied include two different inlet profiles, three outlet boundary conditions, and steady-state versus pulsatile flow cases. Large variations were found in the results, particularly when using different outlet boundary conditions, and the discrepancies were evaluated both quantitatively and qualitatively. The results clearly highlight the importance of the type of boundary condition used when simulating complex cardiovascular models. By restricting the attention to the flow within the aorta and the intercostal branches, the results suggest that prescribing transient simulation and fully developed flow at the inlet are not required. Furthermore, assuming the widely accepted low wall shear stress theory of Caro, it was found that Murray’s law–based outlet boundary condition returns the most physiologically accurate results when compared to in vivo data.
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Wong KKL, Wang D, Ko JKL, Mazumdar J, Le TT, Ghista D. Computational medical imaging and hemodynamics framework for functional analysis and assessment of cardiovascular structures. Biomed Eng Online 2017; 16:35. [PMID: 28327144 PMCID: PMC5359907 DOI: 10.1186/s12938-017-0326-y] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2016] [Accepted: 03/13/2017] [Indexed: 11/10/2022] Open
Abstract
Cardiac dysfunction constitutes common cardiovascular health issues in the society, and has been an investigation topic of strong focus by researchers in the medical imaging community. Diagnostic modalities based on echocardiography, magnetic resonance imaging, chest radiography and computed tomography are common techniques that provide cardiovascular structural information to diagnose heart defects. However, functional information of cardiovascular flow, which can in fact be used to support the diagnosis of many cardiovascular diseases with a myriad of hemodynamics performance indicators, remains unexplored to its full potential. Some of these indicators constitute important cardiac functional parameters affecting the cardiovascular abnormalities. With the advancement of computer technology that facilitates high speed computational fluid dynamics, the realization of a support diagnostic platform of hemodynamics quantification and analysis can be achieved. This article reviews the state-of-the-art medical imaging and high fidelity multi-physics computational analyses that together enable reconstruction of cardiovascular structures and hemodynamic flow patterns within them, such as of the left ventricle (LV) and carotid bifurcations. The combined medical imaging and hemodynamic analysis enables us to study the mechanisms of cardiovascular disease-causing dysfunctions, such as how (1) cardiomyopathy causes left ventricular remodeling and loss of contractility leading to heart failure, and (2) modeling of LV construction and simulation of intra-LV hemodynamics can enable us to determine the optimum procedure of surgical ventriculation to restore its contractility and health This combined medical imaging and hemodynamics framework can potentially extend medical knowledge of cardiovascular defects and associated hemodynamic behavior and their surgical restoration, by means of an integrated medical image diagnostics and hemodynamic performance analysis framework.
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Affiliation(s)
- Kelvin K. L. Wong
- School of Medicine, University of Western Sydney, Campbelltown, Sydney, NSW 2560 Australia
- School of Medicine, Western Sydney University, Locked Bag 1797, Penrith, NSW 2751 Australia
| | - Defeng Wang
- Department of Imaging and Interventional Radiology, The Chinese University of Hong Kong, Shatin, New Territories Hong Kong
| | - Jacky K. L. Ko
- Department of Imaging and Interventional Radiology, The Chinese University of Hong Kong, Shatin, New Territories Hong Kong
| | - Jagannath Mazumdar
- Centre for Biomedical Engineering and School of Electrical and Electronics Engineering, University of Adelaide, Adelaide, SA 5005 Australia
| | - Thu-Thao Le
- National Heart Centre, Mistri Wing, 17 Third Hospital Avenue, Singapore, 168752 Singapore
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Sousa LC, Castro CF, António CC, Sousa F, Santos R, Castro P, Azevedo E. Computational simulation of carotid stenosis and flow dynamics based on patient ultrasound data - A new tool for risk assessment and surgical planning. Adv Med Sci 2016; 61:32-9. [PMID: 26355739 DOI: 10.1016/j.advms.2015.07.009] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2014] [Revised: 06/09/2015] [Accepted: 07/24/2015] [Indexed: 10/23/2022]
Abstract
PURPOSE There is nowadays extensive experimental and computational investigation on the pathophysiology of atherosclerosis, searching correlations between its focal nature and local hemodynamic environment. The goal of this work is to present a methodology for patient-specific hemodynamics study of the carotid artery bifurcation based on the use of ultrasound (US) morphological and blood flow velocity patient data. MATERIALS/METHODS Subject-specific studies were performed for two patients, using a developed finite element code. Geometrical models were obtained from the acquisition of longitudinal and sequential cross-sectional ultrasound images and boundary conditions from Doppler velocity measurements at the common carotid artery. RESULTS There was a good agreement between ultrasound imaging data and computational simulated results. For a normal and a stenosed carotid bifurcation the velocity, wall shear stress (WSS) and WSS descriptors analysis illustrated the extremely complex hemodynamic behavior along the cardiac cycle. Different patterns were found, associated with morphology and hemodynamic patient-specific conditions. High values of time-averaged WSS (TAWSS) were found at stenosis site and for both patients TAWSS fields presented low values within areas of high oscillating shear index and relative residence time values, corresponding to recirculation zones. CONCLUSION Simulated hemodynamic parameters were able to capture the disturbed flow conditions in a normal and a stenosed carotid artery bifurcation, which play an important role in the development of local atherosclerotic plaques. Computational simulations based on clinic US might help improving diagnostic and treatment management of carotid atherosclerosis.
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Mazzitelli R, Boyle F, Murphy E, Renzulli A, Fragomeni G. Numerical prediction of the effect of aortic Left Ventricular Assist Device outflow-graft anastomosis location. Biocybern Biomed Eng 2016. [DOI: 10.1016/j.bbe.2016.01.005] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Hemodynamic impact of abdominal aortic aneurysm stent-graft implantation-induced stenosis. Med Biol Eng Comput 2015; 54:1523-32. [DOI: 10.1007/s11517-015-1425-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2015] [Accepted: 11/17/2015] [Indexed: 12/19/2022]
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Liang F, Oshima M, Huang H, Liu H, Takagi S. Numerical Study of Cerebroarterial Hemodynamic Changes Following Carotid Artery Operation: A Comparison Between Multiscale Modeling and Stand-Alone Three-Dimensional Modeling. J Biomech Eng 2015; 137:101011. [DOI: 10.1115/1.4031457] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2015] [Indexed: 11/08/2022]
Abstract
Free outflow boundary conditions have been widely adopted in hemodynamic model studies, they, however, intrinsically lack the ability to account for the regulatory mechanisms of systemic hemodynamics and hence carry a risk of producing incorrect results when applied to vascular segments with multiple outlets. In the present study, we developed a multiscale model capable of incorporating global cardiovascular properties into the simulation of blood flows in local vascular segments. The multiscale model was constructed by coupling a three-dimensional (3D) model of local arterial segments with a zero-one-dimensional (0-1-D) model of the cardiovascular system. Numerical validation based on an idealized model demonstrated the ability of the multiscale model to preserve reasonable pressure/flow wave transmission among different models. The multiscale model was further calibrated with clinical data to simulate cerebroarterial hemodynamics in a patient undergoing carotid artery operation. The results showed pronounced hemodynamic changes in the cerebral circulation following the operation. Additional numerical experiments revealed that a stand-alone 3D model with free outflow conditions failed to reproduce the results obtained by the multiscale model. These results demonstrated the potential advantage of multiscale modeling over single-scale modeling in patient-specific hemodynamic studies. Due to the fact that the present study was limited to a single patient, studies on more patients would be required to further confirm the findings.
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Affiliation(s)
- Fuyou Liang
- SJTU-CU International Cooperative Research Center, School of Naval Architecture, Ocean and Civil Engineering, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240, China e-mail:
| | - Marie Oshima
- Institute of Industrial Science, The University of Tokyo, Tokyo 153-8505, Japan
| | - Huaxiong Huang
- Department of Mathematics and Statistics, York University, Toronto, ON M3J 1P3 Canada
| | - Hao Liu
- SJTU-CU International Cooperative Research Center, School of Naval Architecture, Ocean and Civil Engineering, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240, China
- Graduate School of Engineering, Chiba University, Chiba-Shi, Chiba 263-8522, Japan
| | - Shu Takagi
- Department of Mechanical Engineering, The University of Tokyo, Tokyo 113-8654, Japan
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Ištvanić T, Vrselja Z, Brkić H, Radić R, Lekšan I, Curic G. Extended Eversion Carotid Endarterectomy: Computation of Hemodynamics. Ann Vasc Surg 2015; 29:1598-605. [PMID: 26319145 DOI: 10.1016/j.avsg.2015.05.034] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2015] [Revised: 05/14/2015] [Accepted: 05/26/2015] [Indexed: 11/16/2022]
Abstract
BACKGROUND Stroke prevention includes surgery for significant stenosis of internal carotid artery (ICA). Consensus on a standard approach lacks and one alternative approach is eversion carotid endarterectomy (eCEA). To overcome disadvantages of eCEA, we developed extended-eversion carotid endarterectomy (exeCEA). Aiming to investigate hemodynamics after different surgical approaches, we created computational fluid dynamics (CFD) models of exeCEA and eCEA with included progressing lumen narrowing, representation of artery restenosis at the incision line. METHODS Blood flow velocities, volume flow rates, and wall shear stress (WSS) were established in carotid arteries from models of eCEA and exeCEA with included increasing groove (1, 1.5, 2, and 2.5 mm) at the "incision line", under input pressure of 120 and 150 mm Hg. RESULTS For the corresponding restenosis grade, models of exeCEA had a larger orifice toward ICA, lower blood flow velocities and higher volume flow rates in ICA, with lower volume flow rates in external carotid artery. WSS values in ICA of exeCEA models were lower than in eCEA models, later reaching the thrombotic range. CONCLUSIONS CFD showed better hemodynamic properties in exeCEA models, indicating presented approach might be better at preserving brain perfusion.
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Affiliation(s)
- Tomislav Ištvanić
- Department of Vascular Surgery of Clinic for Surgery, University Hospital Osijek, Osijek, Croatia
| | - Zvonimir Vrselja
- Department of Radiology, University Hospital Osijek, Osijek, Croatia; Department of Anatomy and Neuroscience, Faculty of Medicine, University of Osijek, Osijek, Croatia
| | - Hrvoje Brkić
- Department of Biophysics, Medical Statistics and Medical Informatics, Faculty of Medicine, University of Osijek, Osijek, Croatia
| | - Radivoje Radić
- Department of Anatomy and Neuroscience, Faculty of Medicine, University of Osijek, Osijek, Croatia
| | - Igor Lekšan
- Department of Anatomy and Neuroscience, Faculty of Medicine, University of Osijek, Osijek, Croatia
| | - Goran Curic
- Department of Medical Chemistry, Biochemistry and Clinical Chemistry, Faculty of Medicine, University of Osijek, Osijek, Croatia.
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Kato T, Sone S, Funamoto K, Hayase T, Kadowaki H, Taniguchi N. Effects of inflow velocity profile on two-dimensional hemodynamic analysis by ordinary and ultrasonic-measurement-integrated simulations. Med Biol Eng Comput 2015; 54:1331-9. [PMID: 26307203 DOI: 10.1007/s11517-015-1376-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2015] [Accepted: 08/12/2015] [Indexed: 11/29/2022]
Abstract
Two-dimensional ultrasonic-measurement-integrated (2D-UMI) simulation correctly reproduces hemodynamics even with an inexact inflow velocity distribution. This study aimed to investigate which is superior, a two-dimensional ordinary (2D-O) simulation with an accurate inflow velocity distribution or a 2D-UMI simulation with an inaccurate one. 2D-O and 2D-UMI simulations were performed for blood flow in a carotid artery with four upstream velocity boundary conditions: a velocity profile with backprojected measured Doppler velocities (condition A), and velocity profiles with a measured Doppler velocity distribution, a parabolic one, and a uniform one, magnitude being obtained by inflow velocity estimation (conditions B, C, and D, respectively). The error of Doppler velocity against the measurement data was sensitive to the inflow velocity distribution in the 2D-O simulation, but not in the 2D-UMI simulation with the inflow velocity estimation. Among the results in conditions B, C, and D, the error in the worst 2D-UMI simulation with condition D was 31 % of that in the best 2D-O simulation with condition B, implying the superiority of the 2D-UMI simulation with an inaccurate inflow velocity distribution over the 2D-O simulation with an exact one. Condition A resulted in a larger error than the other conditions in both the 2D-O and 2D-UMI simulations.
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Affiliation(s)
- Takaumi Kato
- Graduate School of Biomedical Engineering, Tohoku University, Sendai, 980-8579, Japan
| | - Shusaku Sone
- Graduate School of Biomedical Engineering, Tohoku University, Sendai, 980-8579, Japan
| | - Kenichi Funamoto
- Institute of Fluid Science, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, 980-8577, Japan.
| | - Toshiyuki Hayase
- Institute of Fluid Science, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, 980-8577, Japan
| | - Hiroko Kadowaki
- Graduate School of Engineering, Tohoku University, Sendai, 980-8579, Japan
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Aristokleous N, Seimenis I, Georgiou GC, Nicolaides A, Anayiotos AS. The Effect of Head Rotation on the Geometry and Hemodynamics of Healthy Vertebral Arteries. Ann Biomed Eng 2015; 43:1287-97. [DOI: 10.1007/s10439-015-1340-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2015] [Accepted: 05/13/2015] [Indexed: 12/30/2022]
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Zhang P, Sun A, Zhan F, Luan J, Deng X. Hemodynamic study of overlapping bare-metal stents intervention to aortic aneurysm. J Biomech 2014; 47:3524-30. [DOI: 10.1016/j.jbiomech.2014.08.025] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2014] [Revised: 06/16/2014] [Accepted: 08/22/2014] [Indexed: 11/25/2022]
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Sousa LC, Castro CF, António CC, Santos AMF, Dos Santos RM, Castro PMAC, Azevedo E, Tavares JMRS. Toward hemodynamic diagnosis of carotid artery stenosis based on ultrasound image data and computational modeling. Med Biol Eng Comput 2014; 52:971-983. [PMID: 25249277 DOI: 10.1007/s11517-014-1197-z] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2014] [Accepted: 09/17/2014] [Indexed: 11/29/2022]
Abstract
The ability of using non-expensive ultrasound (US) image data together with computer fluid simulation to access various severities of carotid stenosis was inquired in this study. Subject-specific hemodynamic conditions were simulated using a developed finite element solver. Individual structured meshing of the common carotid artery (CCA) bifurcation was built from segmented longitudinal and cross-sectional US images; imposed boundary velocities were based on Doppler US measurements. Simulated hemodynamic parameters such as velocities, wall shear stress (WSS) and derived descriptors were able to predict disturbed flow conditions which play an important role in the development of local atherosclerotic plaques. Hemodynamic features from six individual CCA bifurcations were analyzed. High values of time-averaged WSS (TAWSS) were found at stenosis site. Low values of TAWSS were found at the bulb and at the carotid internal and external branches depending on the particular features of each patient. High oscillating shear index and relative residence time values assigned highly disturbed flows at the same artery surface regions that correlate only moderately with low TAWSS results. Based on clinic US examinations, results provide estimates of flow changes and forces at the carotid artery wall toward the link between hemodynamic behavior and stenosis pathophysiology.
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Affiliation(s)
- Luísa C Sousa
- Faculdade de Engenharia, Instituto de Engenharia Mecânica (IDMEC-Polo FEUP), Universidade do Porto, Rua Dr. Roberto Frias, s/n, 4200-465, Porto, Portugal.
| | - Catarina F Castro
- Faculdade de Engenharia, Instituto de Engenharia Mecânica (IDMEC-Polo FEUP), Universidade do Porto, Rua Dr. Roberto Frias, s/n, 4200-465, Porto, Portugal
| | - Carlos C António
- Faculdade de Engenharia, Instituto de Engenharia Mecânica (IDMEC-Polo FEUP), Universidade do Porto, Rua Dr. Roberto Frias, s/n, 4200-465, Porto, Portugal
| | - André Miguel F Santos
- Faculdade de Engenharia, Instituto de Engenharia Mecânica e Gestão Industrial, Universidade do Porto, Rua Dr. Roberto Frias, s/n, 4200-465, Porto, Portugal
| | - Rosa Maria Dos Santos
- Departamento de Neurologia, Faculdade de Medicina, Hospital São João, Universidade do Porto, Alameda Professor Hernâni Monteiro, 4200-319, Porto, Portugal
| | - Pedro Miguel A C Castro
- Departamento de Neurologia, Faculdade de Medicina, Hospital São João, Universidade do Porto, Alameda Professor Hernâni Monteiro, 4200-319, Porto, Portugal
| | - Elsa Azevedo
- Departamento de Neurologia, Faculdade de Medicina, Hospital São João, Universidade do Porto, Alameda Professor Hernâni Monteiro, 4200-319, Porto, Portugal
| | - João Manuel R S Tavares
- Faculdade de Engenharia, Instituto de Engenharia Mecânica e Gestão Industrial, Universidade do Porto, Rua Dr. Roberto Frias, s/n, 4200-465, Porto, Portugal
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43
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Physiological Significance of Helical Flow in the Arterial System and its Potential Clinical Applications. Ann Biomed Eng 2014; 43:3-15. [DOI: 10.1007/s10439-014-1097-2] [Citation(s) in RCA: 93] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2014] [Accepted: 08/16/2014] [Indexed: 01/12/2023]
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Aristokleous N, Seimenis I, Georgiou GC, Papaharilaou Y, Brott BC, Nicolaides A, Anayiotos AS. Impact of Head Rotation on the Individualized Common Carotid Flow and Carotid Bifurcation Hemodynamics. IEEE J Biomed Health Inform 2014; 18:783-9. [DOI: 10.1109/jbhi.2014.2305575] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Sousa LC, Castro CF, António CC, Santos A, Santos R, Castro P, Azevedo E, Tavares JMR. Haemodynamic conditions of patient-specific carotid bifurcation based on ultrasound imaging. COMPUTER METHODS IN BIOMECHANICS AND BIOMEDICAL ENGINEERING-IMAGING AND VISUALIZATION 2014. [DOI: 10.1080/21681163.2013.875486] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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46
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De Santis G, Conti M, Trachet B, De Schryver T, De Beule M, Degroote J, Vierendeels J, Auricchio F, Segers P, Verdonck P, Verhegghe B. Haemodynamic impact of stent–vessel (mal)apposition following carotid artery stenting: mind the gaps! Comput Methods Biomech Biomed Engin 2013; 16:648-59. [DOI: 10.1080/10255842.2011.629997] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
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47
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Kheyfets VO, O'Dell W, Smith T, Reilly JJ, Finol EA. Considerations for numerical modeling of the pulmonary circulation--a review with a focus on pulmonary hypertension. J Biomech Eng 2013; 135:61011-15. [PMID: 23699723 PMCID: PMC3705788 DOI: 10.1115/1.4024141] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2012] [Revised: 03/25/2013] [Accepted: 04/04/2013] [Indexed: 12/12/2022]
Abstract
Both in academic research and in clinical settings, virtual simulation of the cardiovascular system can be used to rapidly assess complex multivariable interactions between blood vessels, blood flow, and the heart. Moreover, metrics that can only be predicted with computational simulations (e.g., mechanical wall stress, oscillatory shear index, etc.) can be used to assess disease progression, for presurgical planning, and for interventional outcomes. Because the pulmonary vasculature is susceptible to a wide range of pathologies that directly impact and are affected by the hemodynamics (e.g., pulmonary hypertension), the ability to develop numerical models of pulmonary blood flow can be invaluable to the clinical scientist. Pulmonary hypertension is a devastating disease that can directly benefit from computational hemodynamics when used for diagnosis and basic research. In the present work, we provide a clinical overview of pulmonary hypertension with a focus on the hemodynamics, current treatments, and their limitations. Even with a rich history in computational modeling of the human circulation, hemodynamics in the pulmonary vasculature remains largely unexplored. Thus, we review the tasks involved in developing a computational model of pulmonary blood flow, namely vasculature reconstruction, meshing, and boundary conditions. We also address how inconsistencies between models can result in drastically different flow solutions and suggest avenues for future research opportunities. In its current state, the interpretation of this modeling technology can be subjective in a research environment and impractical for clinical practice. Therefore, considerations must be taken into account to make modeling reliable and reproducible in a laboratory setting and amenable to the vascular clinic. Finally, we discuss relevant existing models and how they have been used to gain insight into cardiopulmonary physiology and pathology.
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Affiliation(s)
- V. O. Kheyfets
- Department of Biomedical Engineering,The University of Texas at San Antonio,AET 1.360, One UTSA Circle,San Antonio, TX 78249
| | - W. O'Dell
- Department of Radiation Oncology,University of Florida,Shands Cancer Center,P.O. Box 100385,2033 Mowry Road,Gainesville, FL 32610
| | - T. Smith
- Western Allegheny Health System,Allegheny General Hospital,Gerald McGinnis Cardiovascular Institute,320 East North Avenue,Pittsburgh, PA 15212
| | - J. J. Reilly
- Department of Medicine,The University of Pittsburgh,1218 Scaife Hall,3550 Terrace Street,Pittsburgh, PA 15261
| | - E. A. Finol
- Department of Biomedical Engineering,The University of Texas at San Antonio,AET 1.360, One UTSA Circle,San Antonio, TX 78249e-mail:
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48
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De Santis G, Trachet B, Conti M, De Beule M, Morbiducci U, Mortier P, Segers P, Verdonck P, Verhegghe B. A Computational Study of the Hemodynamic Impact of Open- Versus Closed-Cell Stent Design in Carotid Artery Stenting. Artif Organs 2013; 37:E96-106. [DOI: 10.1111/aor.12046] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Affiliation(s)
| | - Bram Trachet
- bioMMeda-IBiTech; Ghent University; Ghent; Belgium
| | | | | | - Umberto Morbiducci
- Department of Mechanical and Aerospace Engineering; Politecnico di Torino; Turin; Italy
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49
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Dong J, Wong KKL, Tu J. Hemodynamics analysis of patient-specific carotid bifurcation: a CFD model of downstream peripheral vascular impedance. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2013; 29:476-491. [PMID: 23345076 DOI: 10.1002/cnm.2529] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/10/2012] [Revised: 08/19/2012] [Accepted: 10/19/2012] [Indexed: 06/01/2023]
Abstract
The study of cardiovascular models was presented in this paper based on medical image reconstruction and computational fluid dynamics. Our aim is to provide a reality platform for the purpose of flow analysis and virtual intervention outcome predication for vascular diseases. By connecting two porous mediums with transient permeability at the downstream of the carotid bifurcation branches, a downstream peripheral impedance model was developed, and the effect of the downstream vascular bed impedance can be taken into consideration. After verifying its accuracy with a healthy carotid bifurcation, this model was implemented in a diseased carotid bifurcation analysis. On the basis of time-averaged wall shear stress, oscillatory shear index, and the relative residence time, fractions of abnormal luminal surface were highlighted, and the atherosclerosis was assessed from a hemodynamic point of view. The effect of the atherosclerosis on the transient flow division between the two branches because of the existence of plaque was also analysed. This work demonstrated that the proposed downstream peripheral vascular impedance model can be used for computational modelling when the outlets boundary conditions are not available, and successfully presented the potential of using medical imaging and numerical simulation to provide existing clinical prerequisites for diagnosis and therapeutic treatment.
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Affiliation(s)
- Jingliang Dong
- School of Aerospace, Mechanical and Manufacturing Engineering, and Health Innovations Research Institute (HIRi), RMIT University, PO Box 71, Bundoora, VIC 3083, Australia
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50
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Abstract
Extracellular adenine nucleotides ATP and ADP on vascular endothelial cells may play a role in the localization of atherogenesis by regulating the release of nitric oxide from endothelial cells and modulating intracellular calcium levels. To quantitatively investigate the concentration distribution of nucleotides on the luminal surface of the human thoracic aorta, we numerically simulated the transport of nucleotides using an aorta model constructed based on MRI images and analyzed the effects of different factors on nucleotide transport, such as ATP release rate (S(ATP)), pulsatile flow and the absence of ATP in the main blood stream. The numerical results revealed that the combined concentration of ATP and ADP (c(w-ATP+ADP)) on the aortic surface varied from place to place, being relatively low in disturbed flow regions. In addition, c(w-ATP+ADP) was significantly affected by S(ATP). For relatively slow S(ATP), such as the moderate sigmoidal release model, c(w-ATP+ADP) was very low in certain flow regions with low wall shear stress. However, for very rapid S(ATP), such as the rapid linear release model, c(w-ATP+ADP) was relatively high in these same regions. The results also demonstrated that for relatively slow S(ATP), pulsatile blood flow enhanced c(w-ATP+ADP). However, for very rapid S(ATP), pulsatile blood flow would reduce c(w-ATP+ADP). Moreover, the absence of ATP within the main blood stream would not influence the distribution of c(w-ATP+ADP). In conclusion, the concentration distribution of nucleotides along the aortic wall was quite uneven and determined by both the ATP release rate and the blood flow pattern in the aorta.
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Affiliation(s)
- Xiao Liu
- Key Laboratory for Biomechanics and Mechanobiology of the Ministry of Education, School of Biological Science and Medical Engineering, Beihang University, Beijing, China
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