1
|
Soraya H, Sheikholeslami S, Shirpoor A, Nezami Majd F, Naderi R, Rasmi Y. Influence of Maternal Ethanol Exposure on Systemic Hemodynamic Variables and Histopathological Changes in the Aorta Wall of Male Rat Offspring: A Three-month Follow-up. IRANIAN JOURNAL OF MEDICAL SCIENCES 2022; 47:468-476. [PMID: 36117576 PMCID: PMC9445872 DOI: 10.30476/ijms.2021.91047.2205] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/02/2021] [Revised: 08/10/2021] [Accepted: 09/28/2021] [Indexed: 11/04/2022]
Abstract
Background Alcohol consumption in pregnancy is associated with an increased risk of cardiovascular abnormalities, but the mechanisms are unknown. This study evaluated the impact of ethanol exposure on the offspring's aorta structural, functional, and molecular alterations on postnatal (PN) both on days 21 and 90. Methods This experimental study was conducted at Urmia University of Medical Sciences (Urmia, Iran) in 2019. Twenty Pregnant Wistar rats on the seventh day of Gestation Day (GD) were randomly divided into two groups: control and ethanol-treated groups (n=10 per group). From the seventh day of GD throughout lactation, rats in the ethanol group were fed binge alcohol (4.5 g/Kg body weight) once daily. Systemic hemodynamic variables in the offspring were analyzed using waveform contour analysis 90 days after birth. On postnatal days (PN) 21 and 90, aorta wall histological alterations and the level of inflammatory factors were assessed in the aorta of male offspring. The statistical differences were examined via an independent samples t test. P<0.05 was considered to be statistically significant. Results The results revealed that offspring in the ethanol group had higher systolic, diastolic, mean arterial pressure, and dicrotic pressure than the control group (P<0.001). The level of aorta tissue tumor necrosis factor (TNF)-α, intercellular adhesion molecule (ICAM)-1, nuclear factor (NF)-κ, and endothelin-1 were significantly higher in the ethanol offspring group than in the control group (P<0.001). Histopathological changes such as total aorta thickness, tunica media, tunica adventitia, elastin fiber thickness, fiber interval, and elastin/media ratio significantly increased in the aorta of the offspring of the ethanol group compared to the control group 21 and 90 days after birth. Conclusion Our findings suggest that prenatal and early postnatal ethanol exposure-induced cardiovascular abnormalities are, in part, due to predisposing the aorta to atherosclerosis, which was mediated through the aorta wall remodeling and inflammation process.
Collapse
Affiliation(s)
- Hamid Soraya
- Department of Pharmacology, School of Pharmacy, Urmia University of Medical Sciences, Urmia, Iran
| | - Sama Sheikholeslami
- Department of Physiology, School of Medicine, Urmia University of Medical Sciences, Urmia, Iran
| | - Alireza Shirpoor
- Department of Physiology, School of Medicine, Urmia University of Medical Sciences, Urmia, Iran
- Nephrology and Kidney Transplant Research Center, Clinical Research Institute, Urmia University of Medical Sciences, Urmia, Iran
| | - Farideh Nezami Majd
- Department of Physiology, School of Medicine, Urmia University of Medical Sciences, Urmia, Iran
| | - Roya Naderi
- Department of Physiology, School of Medicine, Urmia University of Medical Sciences, Urmia, Iran
- Nephrology and Kidney Transplant Research Center, Clinical Research Institute, Urmia University of Medical Sciences, Urmia, Iran
| | - Yousef Rasmi
- Department of Biochemistry, School of Medicine, Urmia University of Medical Sciences, Urmia, Iran
| |
Collapse
|
2
|
Numerical simulation of haemodynamics of the descending aorta in the non-diabetic and diabetic rabbits. J Biomech 2019; 91:140-150. [DOI: 10.1016/j.jbiomech.2019.05.013] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2018] [Revised: 05/06/2019] [Accepted: 05/13/2019] [Indexed: 12/12/2022]
|
3
|
A novel, FFT-based one-dimensional blood flow solution method for arterial network. Biomech Model Mechanobiol 2019; 18:1311-1334. [PMID: 30955132 PMCID: PMC6748896 DOI: 10.1007/s10237-019-01146-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2018] [Accepted: 03/28/2019] [Indexed: 01/08/2023]
Abstract
In the present work, we propose an FFT-based method for solving blood flow equations in an arterial network with variable properties and geometrical changes. An essential advantage of this approach is in correctly accounting for the vessel skin friction through the use of Womersley solution. To incorporate nonlinear effects, a novel approximation method is proposed to enable calculation of nonlinear corrections. Unlike similar methods available in the literature, the set of algebraic equations required for every harmonic is constructed automatically. The result is a generalized, robust and fast method to accurately capture the increasing pulse wave velocity downstream as well as steepening of the pulse front. The proposed method is shown to be appropriate for incorporating correct convection and diffusion coefficients. We show that the proposed method is fast and accurate and it can be an effective tool for 1D modelling of blood flow in human arterial networks.
Collapse
|
4
|
Pan Q, Wang R, Reglin B, Fang L, Yan J, Cai G, Kuebler WM, Pries AR, Ning G. Pulse wave velocity in the microcirculation reflects both vascular compliance and resistance: Insights from computational approaches. Microcirculation 2018; 25:e12458. [PMID: 29729094 DOI: 10.1111/micc.12458] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2017] [Accepted: 04/26/2018] [Indexed: 01/22/2023]
Abstract
OBJECTIVE PWV is the speed of pulse wave propagation through the circulatory system. mPWV emerges as a novel indicator of hypertension, yet it remains unclear how different vascular properties affect mPWV. We aim to identify the biomechanical determinants of mPWV. METHODS A 1D model was used to simulate PWV in a rat mesenteric microvascular network and, for comparison, in a human macrovascular arterial network. Sensitivity analysis was performed to assess the relationship between PWV and vascular compliance and resistance. RESULTS The 1D model enabled adequate simulation of PWV in both micro- and macrovascular networks. Simulated arterial PWV changed as a function of vascular compliance but not resistance, in that arterial PWV varied at a rate of 0.30 m/s and -6.18 × 10-3 m/s per 10% increase in vascular compliance and resistance, respectively. In contrast, mPWV depended on both vascular compliance and resistance, as it varied at a rate of 2.79 and -2.64 cm/s per 10% increase in the respective parameters. CONCLUSIONS The present study identifies vascular compliance and resistance in microvascular networks as critical determinants of mPWV. We anticipate that mPWV can be utilized as an effective indicator for the assessment of microvascular biomechanical properties.
Collapse
Affiliation(s)
- Qing Pan
- College of Information Engineering, Zhejiang University of Technology, Hangzhou, China
| | - Ruofan Wang
- Key Laboratory of Biomedical Engineering of MOE, Department of Biomedical Engineering, Zhejiang University, Hangzhou, China
| | - Bettina Reglin
- Institute of Physiology, Charité Universitätsmedizin Berlin, Berlin, Germany
| | - Luping Fang
- College of Information Engineering, Zhejiang University of Technology, Hangzhou, China
| | - Jing Yan
- Department of ICU, Zhejiang Hospital, Hangzhou, China
| | - Guolong Cai
- Department of ICU, Zhejiang Hospital, Hangzhou, China
| | - Wolfgang M Kuebler
- Institute of Physiology, Charité Universitätsmedizin Berlin, Berlin, Germany
| | - Axel R Pries
- Institute of Physiology, Charité Universitätsmedizin Berlin, Berlin, Germany.,Deutsches Herzzentrum Berlin, Berlin, Germany
| | - Gangmin Ning
- Key Laboratory of Biomedical Engineering of MOE, Department of Biomedical Engineering, Zhejiang University, Hangzhou, China
| |
Collapse
|
5
|
Charlton PH, Celka P, Farukh B, Chowienczyk P, Alastruey J. Assessing mental stress from the photoplethysmogram: a numerical study. Physiol Meas 2018; 39:054001. [PMID: 29658894 PMCID: PMC5964362 DOI: 10.1088/1361-6579/aabe6a] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2018] [Revised: 03/26/2018] [Accepted: 04/16/2018] [Indexed: 02/03/2023]
Abstract
OBJECTIVE Mental stress is detrimental to cardiovascular health, being a risk factor for coronary heart disease and a trigger for cardiac events. However, it is not currently routinely assessed. The aim of this study was to identify features of the photoplethysmogram (PPG) pulse wave which are indicative of mental stress. APPROACH A numerical model of pulse wave propagation was used to simulate blood pressure signals, from which simulated PPG pulse waves were estimated using a transfer function. Pulse waves were simulated at six levels of stress by changing the model input parameters both simultaneously and individually, in accordance with haemodynamic changes associated with stress. Thirty-two feature measurements were extracted from pulse waves at three measurement sites: the brachial, radial and temporal arteries. Features which changed significantly with stress were identified using the Mann-Kendall monotonic trend test. MAIN RESULTS Seventeen features exhibited significant trends with stress in measurements from at least one site. Three features showed significant trends at all three sites: the time from pulse onset to peak, the time from the dicrotic notch to pulse end, and the pulse rate. More features showed significant trends at the radial artery (15) than the brachial (8) or temporal (7) arteries. Most features were influenced by multiple input parameters. SIGNIFICANCE The features identified in this study could be used to monitor stress in healthcare and consumer devices. Measurements at the radial artery may provide superior performance than the brachial or temporal arteries. In vivo studies are required to confirm these observations.
Collapse
Affiliation(s)
- Peter H Charlton
- Department of Biomedical Engineering, School of
Biomedical Engineering and Imaging Sciences, King’s
College London, King’s Health Partners, St Thomas’ Hospital, London,
SE1 7EH, United Kingdom
| | - Patrick Celka
- Polar Electro
Oy, Professorintie 5, 90440 Kempele,
Finland
| | - Bushra Farukh
- Department of Clinical Pharmacology,
King’s College London, King’s
Health Partners, St Thomas’ Hospital, London, SE1 7EH, United
Kingdom
| | - Phil Chowienczyk
- Department of Clinical Pharmacology,
King’s College London, King’s
Health Partners, St Thomas’ Hospital, London, SE1 7EH, United
Kingdom
| | - Jordi Alastruey
- Department of Biomedical Engineering, School of
Biomedical Engineering and Imaging Sciences, King’s
College London, King’s Health Partners, St Thomas’ Hospital, London,
SE1 7EH, United Kingdom
| |
Collapse
|
6
|
Development of a Cardiovascular Simulator for Studying Pulse Diagnosis Mechanisms. EVIDENCE-BASED COMPLEMENTARY AND ALTERNATIVE MEDICINE 2017; 2017:6790292. [PMID: 29270203 PMCID: PMC5706088 DOI: 10.1155/2017/6790292] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/25/2017] [Accepted: 11/05/2017] [Indexed: 11/23/2022]
Abstract
This research was undertaken to develop a cardiovascular simulator for use in the study of pulse diagnosis. The physical (i.e., pulse wave transmission and reflection) and physiological (i.e., systolic and diastolic pressure, pulse pressure, and mean pressure) characteristics of the radial pulse wave were reproduced by our simulator. The simulator consisted of an arterial component and a pulse-generating component. Computer simulation was used to simplify the arterial component while maintaining the elastic modulus and artery size. To improve the reflected wave characteristics, a palmar arch was incorporated within the simulator. The simulated radial pulse showed good agreement with clinical data.
Collapse
|
7
|
Li X, Liu X, Zhang P, Feng C, Sun A, Kang H, Deng X, Fan Y. Numerical simulation of haemodynamics and low-density lipoprotein transport in the rabbit aorta and their correlation with atherosclerotic plaque thickness. J R Soc Interface 2017; 14:rsif.2017.0140. [PMID: 28424305 DOI: 10.1098/rsif.2017.0140] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2017] [Accepted: 03/20/2017] [Indexed: 12/25/2022] Open
Abstract
Two mechanisms of shear stress and mass transport have been recognized to play an important role in the development of localized atherosclerosis. However, their relationship and roles in atherogenesis are still obscure. It is necessary to investigate quantitatively the correlation among low-density lipoproteins (LDL) transport, haemodynamic parameters and plaque thickness. We simulated blood flow and LDL transport in rabbit aorta using computational fluid dynamics and evaluated plaque thickness in the aorta of a high-fat-diet rabbit. The numerical results show that regions with high luminal LDL concentration tend to have severely negative haemodynamic environments (HEs). However, for regions with moderately and slightly high luminal LDL concentration, the relationship between LDL concentration and the above haemodynamic indicators is not clear cut. Point-by-point correlation with experimental results indicates that severe atherosclerotic plaque corresponds to high LDL concentration and seriously negative HEs, less severe atherosclerotic plaque is related to either moderately high LDL concentration or moderately negative HEs, and there is almost no atherosclerotic plaque in regions with both low LDL concentration and positive HEs. In conclusion, LDL distribution is closely linked to blood flow transport, and the synergetic effects of luminal surface LDL concentration and wall shear stress-based haemodynamic indicators may determine plaque thickness.
Collapse
Affiliation(s)
- Xiaoyin Li
- Key Laboratory for Biomechanics and Mechanobiology of the Ministry of Education, School of Biological Science and Medical Engineering, Beihang University, Beijing 100191, People's Republic of China
| | - Xiao Liu
- Key Laboratory for Biomechanics and Mechanobiology of the Ministry of Education, School of Biological Science and Medical Engineering, Beihang University, Beijing 100191, People's Republic of China
| | - Peng Zhang
- Key Laboratory for Biomechanics and Mechanobiology of the Ministry of Education, School of Biological Science and Medical Engineering, Beihang University, Beijing 100191, People's Republic of China
| | - Chenglong Feng
- Key Laboratory for Biomechanics and Mechanobiology of the Ministry of Education, School of Biological Science and Medical Engineering, Beihang University, Beijing 100191, People's Republic of China
| | - Anqiang Sun
- Key Laboratory for Biomechanics and Mechanobiology of the Ministry of Education, School of Biological Science and Medical Engineering, Beihang University, Beijing 100191, People's Republic of China
| | - Hongyan Kang
- Key Laboratory for Biomechanics and Mechanobiology of the Ministry of Education, School of Biological Science and Medical Engineering, Beihang University, Beijing 100191, People's Republic of China
| | - Xiaoyan Deng
- Key Laboratory for Biomechanics and Mechanobiology of the Ministry of Education, School of Biological Science and Medical Engineering, Beihang University, Beijing 100191, People's Republic of China
| | - Yubo Fan
- Key Laboratory for Biomechanics and Mechanobiology of the Ministry of Education, School of Biological Science and Medical Engineering, Beihang University, Beijing 100191, People's Republic of China .,National Research Center for Rehabilitation Technical Aids, Beijing, People's Republic of China
| |
Collapse
|
8
|
Alastruey J, Xiao N, Fok H, Schaeffter T, Figueroa CA. On the impact of modelling assumptions in multi-scale, subject-specific models of aortic haemodynamics. J R Soc Interface 2017; 13:rsif.2016.0073. [PMID: 27307511 PMCID: PMC4938079 DOI: 10.1098/rsif.2016.0073] [Citation(s) in RCA: 70] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2016] [Accepted: 05/23/2016] [Indexed: 11/22/2022] Open
Abstract
Simulation of haemodynamics has become increasingly popular within the research community. Irrespective of the modelling approach (zero-dimensional (0D), one-dimensional (1D) or three-dimensional (3D)), in vivo measurements are required to personalize the arterial geometry, material properties and boundary conditions of the computational model. Limitations in in vivo data acquisition often result in insufficient information to determine all model parameters and, hence, arbitrary modelling assumptions. Our goal was to minimize and understand the impact of modelling assumptions on the simulated blood pressure, flow and luminal area waveforms by studying a small region of the systemic vasculature—the upper aorta—and acquiring a rich array of non-invasive magnetic resonance imaging and tonometry data from a young healthy volunteer. We first investigated the effect of different modelling assumptions for boundary conditions and material parameters in a 1D/0D simulation framework. Strategies were implemented to mitigate the impact of inconsistencies in the in vivo data. Average relative errors smaller than 7% were achieved between simulated and in vivo waveforms. Similar results were obtained in a 3D/0D simulation framework using the same inflow and outflow boundary conditions and consistent geometrical and mechanical properties. We demonstrated that accurate subject-specific 1D/0D and 3D/0D models of aortic haemodynamics can be obtained using non-invasive clinical data while minimizing the number of arbitrary modelling decisions.
Collapse
Affiliation(s)
- Jordi Alastruey
- Department of Biomedical Engineering, King's College London, St Thomas' Hospital, London, UK
| | - Nan Xiao
- Department of Biomedical Engineering, King's College London, St Thomas' Hospital, London, UK
| | - Henry Fok
- Department of Clinical Pharmacology, King's College London, St Thomas' Hospital, London, UK
| | - Tobias Schaeffter
- Department of Biomedical Engineering, King's College London, St Thomas' Hospital, London, UK
| | - C Alberto Figueroa
- Department of Biomedical Engineering, King's College London, St Thomas' Hospital, London, UK Department of Bioengineering and Surgery, University of Michigan, Ann Arbor, MI, USA
| |
Collapse
|
9
|
Mohamied Y, Sherwin SJ, Weinberg PD. Understanding the fluid mechanics behind transverse wall shear stress. J Biomech 2017; 50:102-109. [PMID: 27863740 PMCID: PMC5236061 DOI: 10.1016/j.jbiomech.2016.11.035] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2016] [Accepted: 11/05/2016] [Indexed: 11/04/2022]
Abstract
The patchy distribution of atherosclerosis within arteries is widely attributed to local variation in haemodynamic wall shear stress (WSS). A recently-introduced metric, the transverse wall shear stress (transWSS), which is the average over the cardiac cycle of WSS components perpendicular to the temporal mean WSS vector, correlates particularly well with the pattern of lesions around aortic branch ostia. Here we use numerical methods to investigate the nature of the arterial flows captured by transWSS and the sensitivity of transWSS to inflow waveform and aortic geometry. TransWSS developed chiefly in the acceleration, peak systolic and deceleration phases of the cardiac cycle; the reverse flow phase was too short, and WSS in diastole was too low, for these periods to have a significant influence. Most of the spatial variation in transWSS arose from variation in the angle by which instantaneous WSS vectors deviated from the mean WSS vector rather than from variation in the magnitude of the vectors. The pattern of transWSS was insensitive to inflow waveform; only unphysiologically high Womersley numbers produced substantial changes. However, transWSS was sensitive to changes in geometry. The curvature of the arch and proximal descending aorta were responsible for the principal features, the non-planar nature of the aorta produced asymmetries in the location and position of streaks of high transWSS, and taper determined the persistence of the streaks down the aorta. These results reflect the importance of the fluctuating strength of Dean vortices in generating transWSS.
Collapse
Affiliation(s)
- Yumnah Mohamied
- Department of Aeronautics, Imperial College London, United Kingdom; Department of Bioengineering, Imperial College London, United Kingdom
| | | | - Peter D Weinberg
- Department of Bioengineering, Imperial College London, United Kingdom.
| |
Collapse
|
10
|
Danilov A, Ivanov Y, Pryamonosov R, Vassilevski Y. Methods of graph network reconstruction in personalized medicine. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2016; 32:e02754. [PMID: 26462139 DOI: 10.1002/cnm.2754] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/16/2015] [Revised: 10/06/2015] [Accepted: 10/09/2015] [Indexed: 06/05/2023]
Abstract
The paper addresses methods for generation of individualized computational domains on the basis of medical imaging dataset. The computational domains will be used in one-dimensional (1D) and three-dimensional (3D)-1D coupled hemodynamic models. A 1D hemodynamic model employs a 1D network of a patient-specific vascular network with large number of vessels. The 1D network is the graph with nodes in the 3D space which bears additional geometric data such as length and radius of vessels. A 3D hemodynamic model requires a detailed 3D reconstruction of local parts of the vascular network. We propose algorithms which extend the automated segmentation of vascular and tubular structures, generation of centerlines, 1D network reconstruction, correction, and local adaptation. We consider two modes of centerline representation: (i) skeletal segments or sets of connected voxels and (ii) curved paths with corresponding radii. Individualized reconstruction of 1D networks depends on the mode of centerline representation. Efficiency of the proposed algorithms is demonstrated on several examples of 1D network reconstruction. The networks can be used in modeling of blood flows as well as other physiological processes in tubular structures. Copyright © 2015 John Wiley & Sons, Ltd.
Collapse
Affiliation(s)
- A Danilov
- Institute of Numerical Mathematics RAS, 8 Gubkina St., Moscow, 119333, Russia
- Moscow Institute of Physics and Technology, 9 Institutskii Lane, Moscow, 141700, Russia
| | - Yu Ivanov
- Institute of Numerical Mathematics RAS, 8 Gubkina St., Moscow, 119333, Russia
- Moscow Institute of Physics and Technology, 9 Institutskii Lane, Moscow, 141700, Russia
| | - R Pryamonosov
- Institute of Numerical Mathematics RAS, 8 Gubkina St., Moscow, 119333, Russia
- Moscow Institute of Physics and Technology, 9 Institutskii Lane, Moscow, 141700, Russia
- Moscow State University, 1 Leninskie gory, Moscow, 119991, Russia
| | - Yu Vassilevski
- Institute of Numerical Mathematics RAS, 8 Gubkina St., Moscow, 119333, Russia
- Moscow Institute of Physics and Technology, 9 Institutskii Lane, Moscow, 141700, Russia
- Moscow State University, 1 Leninskie gory, Moscow, 119991, Russia
| |
Collapse
|
11
|
Acosta S, Puelz C, Riviére B, Penny DJ, Rusin CG. Numerical Method of Characteristics for One-Dimensional Blood Flow. JOURNAL OF COMPUTATIONAL PHYSICS 2015; 294:96-109. [PMID: 25931614 PMCID: PMC4410450 DOI: 10.1016/j.jcp.2015.03.045] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Mathematical modeling at the level of the full cardiovascular system requires the numerical approximation of solutions to a one-dimensional nonlinear hyperbolic system describing flow in a single vessel. This model is often simulated by computationally intensive methods like finite elements and discontinuous Galerkin, while some recent applications require more efficient approaches (e.g. for real-time clinical decision support, phenomena occurring over multiple cardiac cycles, iterative solutions to optimization/inverse problems, and uncertainty quantification). Further, the high speed of pressure waves in blood vessels greatly restricts the time step needed for stability in explicit schemes. We address both cost and stability by presenting an efficient and unconditionally stable method for approximating solutions to diagonal nonlinear hyperbolic systems. Theoretical analysis of the algorithm is given along with a comparison of our method to a discontinuous Galerkin implementation. Lastly, we demonstrate the utility of the proposed method by implementing it on small and large arterial networks of vessels whose elastic and geometrical parameters are physiologically relevant.
Collapse
Affiliation(s)
- Sebastian Acosta
- Department of Pediatric Cardiology, Baylor College of Medicine, Texas
| | - Charles Puelz
- Department of Computational and Applied Mathematics, Rice University, Texas
| | - Béatrice Riviére
- Department of Computational and Applied Mathematics, Rice University, Texas
| | - Daniel J. Penny
- Department of Pediatric Cardiology, Baylor College of Medicine, Texas
- Department of Pediatric Medicine – Cardiology, Texas Children’s Hospital
| | - Craig G. Rusin
- Department of Pediatric Cardiology, Baylor College of Medicine, Texas
| |
Collapse
|
12
|
Mynard JP, Valen-Sendstad K. A unified method for estimating pressure losses at vascular junctions. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2015; 31:e02717. [PMID: 25833463 DOI: 10.1002/cnm.2717] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/12/2015] [Revised: 03/18/2015] [Accepted: 03/20/2015] [Indexed: 06/04/2023]
Abstract
In reduced-order (0D/1D) blood or respiratory flow models, pressure losses at junctions are usually neglected. However, these may become important where velocities are high and significant flow redirection occurs. Current methods for estimating losses rely on relatively complex empirical equations that are only valid for specific junction geometries and flow regimes. In pulsatile multi-directional flows, switching between empirical equations upon reversing flow may introduce unrealistic discontinuities in simulated haemodynamic waveforms. Drawing from work by Bassett et al. (SAE Trans 112:565-583, 2003), we therefore developed a unified method (Unified0D) for estimating loss coefficients that can be applied to any junction (i.e. any number of branches at any angle) and any flow regime. Discontinuities in simulated waveforms were avoided by extending Bassett et al.'s control volume-based method to incorporate a 'pseudodatum' supplier branch, an imaginary effective vessel containing all inflow to the junction. Energy exchange between diverging flow streams was also accounted for empirically. The formulation was validated using high resolution computational fluid dynamics in a wide range flow conditions and junction configurations. In a pulsatile 1D simulation exhibiting transitions between four different flow regimes, the new formulation produced smooth transitions in calculated pressure losses.
Collapse
Affiliation(s)
- Jonathan P Mynard
- Biomedical Simulation Laboratory, Department of Mechanical and Industrial Engineering, University of Toronto, Toronto, ON, Canada
- Heart Research, Clinical Sciences, Murdoch Childrens Research Institute, Parkville, VIC, Australia
- Department of Paediatrics, University of Melbourne, Parkville, VIC, Australia
| | - Kristian Valen-Sendstad
- Biomedical Simulation Laboratory, Department of Mechanical and Industrial Engineering, University of Toronto, Toronto, ON, Canada
- Center for Biomedical Computing, Simula Research Laboratory, Lysaker, Norway
| |
Collapse
|
13
|
Gaddum NR, Keehn L, Guilcher A, Gomez A, Brett S, Beerbaum P, Schaeffter T, Chowienczyk P. Altered dependence of aortic pulse wave velocity on transmural pressure in hypertension revealing structural change in the aortic wall. Hypertension 2015; 65:362-9. [PMID: 25403607 DOI: 10.1161/hypertensionaha.114.04370] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Aortic pulse wave velocity (aPWV), a major prognostic indicator of cardiovascular events, may be augmented in hypertension as a result of the aorta being stretched by a higher distending blood pressure or by a structural change. We used a novel technique to modulate intrathoracic pressure and thus aortic transmural pressure (TMP) to examine the variation of intrathoracic aPWV with TMP in hypertensive (n=20; mean±SD age, 52.1±15.3 years; blood pressure, 159.6±21.2/92.0±15.9 mm Hg) and normotensive (n=20; age, 55.5±11.1 years; blood pressure, 124.5±11.9/72.6±9.1 mm Hg) subjects. aPWV was measured using dual Doppler probes to insonate the right brachiocephalic artery and aorta at the level of the diaphragm. Resting aPWV was greater in hypertensive compared with normotensive subjects (897±50 cm/s versus 784±43 cm/s; P<0.05). aPWV was equal in hypertensive and normotensive subjects when measured at a TMP of 96 mm Hg. However, dependence of aPWV on TMP in normotensive subjects was greater than that in hypertensive subjects (9.6±1.6 versus 3.8±0.7 cm/s per mm Hg increase in TMP, respectively, means±SEM; P<0.01). This experimental behavior was best explained by a theoretical model incorporating strain-induced recruitment of stiffer fibers in normotensive subjects and fully recruited stiffer fibers in hypertensive subjects. These results explain previous contradictory findings with respect to isobaric aPWV in hypertensive compared with normotensive subjects. They suggest that hypertension is associated with a profound change in aortic wall mechanical properties possibly because of destruction of elastin leading to less strain-induced stiffening and predisposition to aortic dissection.
Collapse
Affiliation(s)
- Nicholas R Gaddum
- From the Division of Imaging Sciences and Biomedical Engineering, St. Thomas' Hospital, King's College London, London, United Kingdom (N.R.G., A. Gomez, T.S.); King's College London British Heart Foundation Centre, Department of Clinical Pharmacology, St Thomas' Hospital, London, United Kingdom (L.K., A. Guilcher, S.B., P.C.); and Department of Pediatric Cardiology and Pediatric Intensive Care Medicine, Hannover Medical School, Hannover, Germany (P.B.)
| | - Louise Keehn
- From the Division of Imaging Sciences and Biomedical Engineering, St. Thomas' Hospital, King's College London, London, United Kingdom (N.R.G., A. Gomez, T.S.); King's College London British Heart Foundation Centre, Department of Clinical Pharmacology, St Thomas' Hospital, London, United Kingdom (L.K., A. Guilcher, S.B., P.C.); and Department of Pediatric Cardiology and Pediatric Intensive Care Medicine, Hannover Medical School, Hannover, Germany (P.B.)
| | - Antoine Guilcher
- From the Division of Imaging Sciences and Biomedical Engineering, St. Thomas' Hospital, King's College London, London, United Kingdom (N.R.G., A. Gomez, T.S.); King's College London British Heart Foundation Centre, Department of Clinical Pharmacology, St Thomas' Hospital, London, United Kingdom (L.K., A. Guilcher, S.B., P.C.); and Department of Pediatric Cardiology and Pediatric Intensive Care Medicine, Hannover Medical School, Hannover, Germany (P.B.)
| | - Alberto Gomez
- From the Division of Imaging Sciences and Biomedical Engineering, St. Thomas' Hospital, King's College London, London, United Kingdom (N.R.G., A. Gomez, T.S.); King's College London British Heart Foundation Centre, Department of Clinical Pharmacology, St Thomas' Hospital, London, United Kingdom (L.K., A. Guilcher, S.B., P.C.); and Department of Pediatric Cardiology and Pediatric Intensive Care Medicine, Hannover Medical School, Hannover, Germany (P.B.)
| | - Sally Brett
- From the Division of Imaging Sciences and Biomedical Engineering, St. Thomas' Hospital, King's College London, London, United Kingdom (N.R.G., A. Gomez, T.S.); King's College London British Heart Foundation Centre, Department of Clinical Pharmacology, St Thomas' Hospital, London, United Kingdom (L.K., A. Guilcher, S.B., P.C.); and Department of Pediatric Cardiology and Pediatric Intensive Care Medicine, Hannover Medical School, Hannover, Germany (P.B.)
| | - Philipp Beerbaum
- From the Division of Imaging Sciences and Biomedical Engineering, St. Thomas' Hospital, King's College London, London, United Kingdom (N.R.G., A. Gomez, T.S.); King's College London British Heart Foundation Centre, Department of Clinical Pharmacology, St Thomas' Hospital, London, United Kingdom (L.K., A. Guilcher, S.B., P.C.); and Department of Pediatric Cardiology and Pediatric Intensive Care Medicine, Hannover Medical School, Hannover, Germany (P.B.)
| | - Tobias Schaeffter
- From the Division of Imaging Sciences and Biomedical Engineering, St. Thomas' Hospital, King's College London, London, United Kingdom (N.R.G., A. Gomez, T.S.); King's College London British Heart Foundation Centre, Department of Clinical Pharmacology, St Thomas' Hospital, London, United Kingdom (L.K., A. Guilcher, S.B., P.C.); and Department of Pediatric Cardiology and Pediatric Intensive Care Medicine, Hannover Medical School, Hannover, Germany (P.B.)
| | - Philip Chowienczyk
- From the Division of Imaging Sciences and Biomedical Engineering, St. Thomas' Hospital, King's College London, London, United Kingdom (N.R.G., A. Gomez, T.S.); King's College London British Heart Foundation Centre, Department of Clinical Pharmacology, St Thomas' Hospital, London, United Kingdom (L.K., A. Guilcher, S.B., P.C.); and Department of Pediatric Cardiology and Pediatric Intensive Care Medicine, Hannover Medical School, Hannover, Germany (P.B.).
| |
Collapse
|
14
|
Khalifé M, Decoene A, Caetano F, de Rochefort L, Durand E, Rodríguez D. Estimating absolute aortic pressure using MRI and a one-dimensional model. J Biomech 2014; 47:3390-9. [DOI: 10.1016/j.jbiomech.2014.07.018] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2014] [Revised: 06/20/2014] [Accepted: 07/22/2014] [Indexed: 11/26/2022]
|
15
|
Shirpoor A, Khadem Ansari MH, Heshmatian B, Ilkhanizadeh B, Noruzi L, Abdollahzadeh N, Saboory E. Decreased blood pressure with a corresponding decrease in adhesive molecules in diabetic rats caused by vitamin E administration. J Diabetes 2012; 4:362-8. [PMID: 22236396 DOI: 10.1111/j.1753-0407.2012.00184.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
Abstract
BACKGROUND Hypertension is one of the important clinical problems of diabetic cardiovascular disease. The aim of this study was to determine the effect of vitamin E on blood pressure parameters and adhesive molecule amounts in diabetic rats. METHODS Twenty-four male Wistar rats were divided into three groups (each of n = 8): the controls (C), non-treated diabetic (NTD), and vitamin E treated diabetic (VETD) groups. A single intraperitoneal injection of buffered streptozotocin (60 mg/kg) in cold sodium citrate (pH 4.5) was used to induce diabetes. The VETD group received 300 mg of vitamin E daily intragastrically for 6 weeks. Systolic and diastolic blood pressure, mean arterial pressure, as well as the dicrotic pressure, crest time, systolic and diastolic periods, and plasma levels of intercellular adhesion molecule-1 and E-selectin were measured after 6 weeks. RESULTS The results revealed that there was a significant increase in systolic and diastolic blood pressures, mean arterial pressure, crest time, systolic duration, and the amount of sICAM-1 and E-selectin in diabetic rats. There was no significant difference in the heart rate or cardiac cyclic duration among the different groups. Significant improvement of blood pressure parameters as well as attenuation of the elevated ICAM-1 and E-selectin amounts was found in the vitamin E treated group. CONCLUSIONS These findings indicate that vitamin E significantly improved blood pressure elevation in diabetic rats and that these effects could be associated with reducing adhesive molecule and antioxidant properties of vitamin E.
Collapse
Affiliation(s)
- Alireza Shirpoor
- Department of Physiology, Faculty of Medicine, Urmia Medical University, Urmia, Iran.
| | | | | | | | | | | | | |
Collapse
|
16
|
Shirpoor A, Salami S, Khadem-Ansari MH, Heshmatian B, Ilkhanizadeh B. Long-term ethanol consumption initiates atherosclerosis in rat aorta through inflammatory stress and endothelial dysfunction. Vascul Pharmacol 2012; 57:72-7. [DOI: 10.1016/j.vph.2012.04.001] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2011] [Revised: 03/08/2012] [Accepted: 04/02/2012] [Indexed: 01/12/2023]
|
17
|
Donetti E, Decorato I, Bertarelli E, Baetta R, Corsini A, Sforza C, Dubini G. Fluid–Structure Computational Analysis to Investigate the Link between Early Atherogenic Events and the Hemodynamic Environment in an Experimental Model of Intimal Thickening. Cardiovasc Eng Technol 2012. [DOI: 10.1007/s13239-012-0100-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
|
18
|
Effect of aortic taper on patterns of blood flow and wall shear stress in rabbits: association with age. Atherosclerosis 2012; 223:114-21. [PMID: 22658260 DOI: 10.1016/j.atherosclerosis.2012.04.020] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/14/2011] [Revised: 04/23/2012] [Accepted: 04/28/2012] [Indexed: 11/20/2022]
Abstract
OBJECTIVE The distribution of atherosclerotic lesions changes with age in human and rabbit aortas. We investigated if this can be explained by changes in patterns of blood flow and wall shear stress. METHODS The luminal geometry of thoracic aortas from immature and mature rabbits was obtained by micro-CT of vascular corrosion casts. Blood flow was computed and average maps of wall shear stress were derived. RESULTS The branch anatomy of the aortic arch varied widely between animals. Wall shear was increased downstream and to a lesser extent upstream of intercostal branch ostia, and a stripe of high shear was located on the dorsal descending aortic wall. The stripe was associated with two vortices generated by aortic arch curvature; their persistence into the descending aorta depended on aortic taper and was more pronounced in mature geometries. These results were not sensitive to the modelling assumptions. CONCLUSIONS Blood flow characteristics in the rabbit aorta were affected by the degree of taper, which tends to increase with age in the aortic arch and strengthens secondary flows into the descending aorta. Previously-observed lesion distributions correlated better with high than low shear, and age-related changes around branch ostia were not explained by the flow patterns.
Collapse
|
19
|
Waters SL, Alastruey J, Beard DA, Bovendeerd PHM, Davies PF, Jayaraman G, Jensen OE, Lee J, Parker KH, Popel AS, Secomb TW, Siebes M, Sherwin SJ, Shipley RJ, Smith NP, van de Vosse FN. Theoretical models for coronary vascular biomechanics: progress & challenges. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2011; 104:49-76. [PMID: 21040741 PMCID: PMC3817728 DOI: 10.1016/j.pbiomolbio.2010.10.001] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/20/2009] [Revised: 09/17/2010] [Accepted: 10/06/2010] [Indexed: 01/09/2023]
Abstract
A key aim of the cardiac Physiome Project is to develop theoretical models to simulate the functional behaviour of the heart under physiological and pathophysiological conditions. Heart function is critically dependent on the delivery of an adequate blood supply to the myocardium via the coronary vasculature. Key to this critical function of the coronary vasculature is system dynamics that emerge via the interactions of the numerous constituent components at a range of spatial and temporal scales. Here, we focus on several components for which theoretical approaches can be applied, including vascular structure and mechanics, blood flow and mass transport, flow regulation, angiogenesis and vascular remodelling, and vascular cellular mechanics. For each component, we summarise the current state of the art in model development, and discuss areas requiring further research. We highlight the major challenges associated with integrating the component models to develop a computational tool that can ultimately be used to simulate the responses of the coronary vascular system to changing demands and to diseases and therapies.
Collapse
Affiliation(s)
- Sarah L Waters
- Oxford Centre for Industrial and Applied mathematics, Mathematical Institute, 24-29 St Giles', Oxford, OX1 3LB, UK.
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|