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Kozuń M, Chwiłkowska A, Pezowicz C, Kobielarz M. Influence of atherosclerosis on anisotropy and incompressibility of the human thoracic aortic wall. Biocybern Biomed Eng 2021. [DOI: 10.1016/j.bbe.2020.11.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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2
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Electrospun cellulose Nano fibril reinforced PLA/PBS composite scaffold for vascular tissue engineering. JOURNAL OF POLYMER RESEARCH 2019. [DOI: 10.1007/s10965-019-1772-y] [Citation(s) in RCA: 43] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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Sigaeva T, Sommer G, Holzapfel GA, Di Martino ES. Anisotropic residual stresses in arteries. J R Soc Interface 2019; 16:20190029. [PMID: 30958201 PMCID: PMC6408350 DOI: 10.1098/rsif.2019.0029] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2019] [Accepted: 02/06/2019] [Indexed: 12/29/2022] Open
Abstract
The paper provides a deepened insight into the role of anisotropy in the analysis of residual stresses in arteries. Residual deformations are modelled following Holzapfel and Ogden (Holzapfel and Ogden 2010, J. R. Soc. Interface 7, 787-799. ( doi:10.1098/rsif.2009.0357 )), which is based on extensive experimental data on human abdominal aortas (Holzapfel et al. 2007, Ann. Biomed. Eng. 35, 530-545. ( doi:10.1007/s10439-006-9252-z )) and accounts for both circumferential and axial residual deformations of the individual layers of arteries-intima, media and adventitia. Each layer exhibits distinctive nonlinear and anisotropic mechanical behaviour originating from its unique microstructure; therefore, we use the most general form of strain-energy function (Holzapfel et al. 2015, J. R. Soc. Interface 12, 20150188. ( doi:10.1098/rsif.2015.0188 )) to derive residual stresses for each layer individually. Finally, the systematic experimental data (Niestrawska et al. 2016, J. R. Soc. Interface 13, 20160620. ( doi:10.1098/rsif.2016.0620 )) on both mechanical and structural properties of the different layers of the human abdominal aorta facilitate our discussion on (i) the importance of anisotropy in modelling residual stresses; (ii) the variability of residual stresses within the same class of tissue, the abdominal aorta; (iii) the limitations of conventional opening angle method to account for complex residual deformations; and (iv) the effect of residual stresses on the loaded configuration of the aorta mimicking in vivo conditions.
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Affiliation(s)
- Taisiya Sigaeva
- Department of Civil Engineering and Centre for Bioengineering Research and Education, Schulich School of Engineering, University of Calgary, Calgary, Canada
| | - Gerhard Sommer
- Institute of Biomechanics, Graz University of Technology, Graz, Austria
| | - Gerhard A. Holzapfel
- Institute of Biomechanics, Graz University of Technology, Graz, Austria
- Faculty of Engineering Science and Technology, Norwegian University of Science and Technology (NTNU), Trondheim, Norway
| | - Elena S. Di Martino
- Department of Civil Engineering and Centre for Bioengineering Research and Education, Schulich School of Engineering, University of Calgary, Calgary, Canada
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Biomechanical property and modelling of venous wall. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2018; 133:56-75. [DOI: 10.1016/j.pbiomolbio.2017.11.004] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2017] [Revised: 11/13/2017] [Accepted: 11/15/2017] [Indexed: 11/18/2022]
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5
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Rapid fabrication of highly porous and biocompatible composite textile tubular scaffold for vascular tissue engineering. Eur Polym J 2017. [DOI: 10.1016/j.eurpolymj.2017.08.054] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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6
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Munger KA, Downey TM, Haberer B, Pohlson K, Marshall LL, Utecht RE. A novel photochemical cross-linking technology to improve luminal gain, vessel compliance, and buckling post-angioplasty in porcine arteries. J Biomed Mater Res B Appl Biomater 2015; 104:375-84. [PMID: 25823876 DOI: 10.1002/jbm.b.33373] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2014] [Revised: 11/25/2014] [Accepted: 01/09/2015] [Indexed: 01/18/2023]
Abstract
UNLABELLED Development of substituted 1,8-naphthalimides for photochemical cross-linking of biomolecules is the focus of this research. This study describes limited cross-linking of collagen in the artery wall to control recoil and buckling in arteries following balloon angioplasty. Isolated porcine arteries were overstretched (25%) with balloon angioplasty (BA) +/- light-activated naphthalimide treatment (NVS). Lumen size and recoil were measured as retention of stretch after angioplasty. Cross-sectional compliance and distensibility coefficients were measured as slope of cross-sectional area versus increasing hydrostatic pressure. Buckling was measured, with 30% axial pre-stretch and 200 mmHg, as deviation from the center line. Electron microscopy evaluation of collagen fibers was conducted. RESULTS Uninjured arteries have low compliance and low levels of buckling, whereas the BA-injured arteries demonstrated much greater compliance and buckling behavior. Treatment of the injured artery with NVS reduced buckling and demonstrated compliance midway between the two groups while retaining the increased luminal diameter imparted by angioplasty compared to untreated vessels. In summary, limited collagen cross-linking with NVS treatment resulted in lumen retention, as well as improved compliance without the accompanying rigidity and stiffness of conventional stent therapy or current cross-linking materials. This treatment shows great promise for dilation, repair and strengthening of arteries damaged by injury or vascular disease.
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Affiliation(s)
- Karen A Munger
- Avera Research Institute, Applied Research, Sioux Falls, South Dakota, 57017
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Hosseinkhah N, Chen H, Matula TJ, Burns PN, Hynynen K. Mechanisms of microbubble-vessel interactions and induced stresses: a numerical study. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2013; 134:1875-85. [PMID: 23967921 PMCID: PMC3765296 DOI: 10.1121/1.4817843] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/03/2013] [Revised: 05/23/2013] [Accepted: 07/18/2013] [Indexed: 05/22/2023]
Abstract
Oscillating microbubbles within microvessels could induce stresses that lead to bioeffects or vascular damage. Previous work has attributed vascular damage to the vessel expansion or bubble jet. However, ultra-high speed images of recent studies suggest that it could happen due to the vascular invagination. Numerical simulations of confined bubbles could provide insight into understanding the mechanism behind bubble-vessel interactions. In this study, a finite element model of a coupled bubble/fluid/vessel system was developed and validated with experimental data. Also, for a more realistic study viscoelastic properties of microvessels were assessed and incorporated into this comprehensive numerical model. The wall shear stress (WSS) and circumferential stress (CS), metrics of vascular damage, were calculated from these simulations. Resultant amplitudes of oscillation were within 15% of those measured in experiments (four cases). Among the experimental cases, it was numerically found that maximum WSS values were between 1.1-18.3 kPa during bubble expansion and 1.5-74 kPa during bubble collapse. CS was between 0.43-2.2 MPa during expansion and 0.44-6 MPa while invaginated. This finding confirmed that vascular damage could occur during vascular invaginations. Predicted thresholds in which these stresses are higher during vessel invagination were calculated from simulations.
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Affiliation(s)
- N Hosseinkhah
- Department of Medical Biophysics, University of Toronto, Sunnybrook Research Institute, 2075 Bayview Avenue, Room C713, Toronto, Ontario M4N 3M5, Canada.
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Hosseinkhah N, Hynynen K. A three-dimensional model of an ultrasound contrast agent gas bubble and its mechanical effects on microvessels. Phys Med Biol 2012; 57:785-808. [PMID: 22252221 DOI: 10.1088/0031-9155/57/3/785] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Ultrasound contrast agents inside a microvessel, when driven by ultrasound, oscillate and induce mechanical stresses on the vessel wall. These mechanical stresses can produce beneficial therapeutic effects but also induce vessel rupture if the stresses are too high. Therefore, it is important to use sufficiently low pressure amplitudes to avoid rupturing the vessels while still inducing the desired therapeutic effects. In this work, we developed a comprehensive three-dimensional model of a confined microbubble inside a vessel while considering the bubble shell properties, blood viscosity, vessel wall curvature and the mechanical properties of the vessel wall. Two bubble models with the assumption of a spherical symmetric bubble and a simple asymmetrical bubble were simulated. This work was validated with previous experimental results and enabled us to evaluate the microbubbles' behaviour and the resulting mechanical stresses induced on the vessel walls. In this study, the fluid shear and circumferential stresses were evaluated as indicators of the mechanical stresses. The effects of acoustical parameters, vessel viscoelasticity and rigidity, vessel/bubble size and off-centre bubbles on bubble behaviour and stresses on the vessel were investigated. The fluid shear and circumferential stresses acting on the vessel varied with time and location. As the frequency changed, the microbubble oscillated with the highest amplitude at its resonance frequency which was different from the resonance frequency of an unbound bubble. The bubble resonance frequency increased as the rigidity of a flexible vessel increased. The fluid shear and circumferential stresses peaked at frequencies above the bubble's resonance frequency. The more rigid the vessels were, the more damped the bubble oscillations. The synergistic effect of acoustic frequency and vessel elasticity had also been investigated since the circumferential stress showed either an increasing trend or a decreasing one versus the vessel rigidity at different acoustic frequencies. When the acoustic pressure was increased from 52 to 680 kPa, the maximum bubble radius increase by 2.5 fold, and the maximum shear and circumferential stress increased by 15.7 and 18.3 fold, respectively. The shear stress was largest when the acoustic frequency was higher (3.25 MHz) and the ratio of the vessel radius to the bubble radius was lower. The circumferential stress was largest when the bubble wall was closer to the vessel wall. An oscillating off-centre bubble forms a mushroom shape with the most damping on the points closest to the vessel wall.
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Affiliation(s)
- N Hosseinkhah
- University of Toronto, 2075 Bayview Avenue, Rm C713, Toronto, Ontario M4N 3M5, Canada.
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Sokolis DP. A passive strain-energy function for elastic and muscular arteries: correlation of material parameters with histological data. Med Biol Eng Comput 2011; 48:507-18. [PMID: 20390462 DOI: 10.1007/s11517-010-0598-x] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2009] [Accepted: 03/18/2010] [Indexed: 10/19/2022]
Abstract
A plethora of phenomenological and structure-motivated constitutive models have thus far been used as pseudoelastic descriptors in arterial biomechanics, but their parameters have not been explicitly correlated with histology. This study associated biaxial histological data with strain-energy function (SEF) parameters derived from uniaxial tension data of arteries from different topographical sites (carotid artery vs. thoracic aorta vs. femoral artery). A two-term SEF fitted the passive stress-strain data of healthy porcine tissue, justified by the biphasic response characterizing elastin-rich tissues. Selection of a quadratic (orthotropic) over the neo-Hookean (isotropic) term was dictated by the directional dissimilarities in low-stress mechanical response, consistent with our histological data indicating orthotropic symmetry for unstressed elastin. Use of the exponential term was dictated by mechanical dissimilarities at high stresses and variations in unstressed collagen composition and orientation. Accurate fits were attained; topographical variations and anisotropy in material parameters were accounted by respective variations in histomorphometrical data.
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Affiliation(s)
- Dimitrios P Sokolis
- Laboratory of Biomechanics, Foundation of Biomedical Research, Academy of Athens, Athens, 11527, Greece.
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Martynov S, Stride E, Saffari N. The natural frequencies of microbubble oscillation in elastic vessels. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2009; 126:2963-72. [PMID: 20000909 DOI: 10.1121/1.3243292] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
A theoretical model for the dynamics of a bubble in an elastic blood vessel is applied to study numerically the effect of confinement on the free oscillations of a bubble. The vessel wall deformations are described using a lumped-parameter membrane-type model, which is coupled to the Navier-Stokes equations for the fluid motion inside the vessel. It is shown that the bubble oscillations in a finite-length vessel are characterized by a spectrum of frequencies, with distinguishable high-frequency and low-frequency modes. The frequency of the high-frequency mode increases with the vessel elastic modulus and, for a thin-wall vessel, can be higher than the natural frequency of bubble oscillations in an unconfined liquid. In the limiting case of an infinitely stiff vessel wall, the frequency of the low-frequency mode approaches the well-known solution for a bubble confined in a rigid vessel. In order to interpret the results, a simple two-degree-of-freedom model is applied. The results suggest that in order to maximize deposition of acoustic energy, a bubble confined in a long elastic vessel has to be excited at frequencies higher than the natural frequency of the equivalent unconfined bubble.
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Affiliation(s)
- Sergey Martynov
- Department of Mechanical Engineering, University College London, Torrington Place, London WC1E 7JE, United Kingdom.
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Akhtar R, Schwarzer N, Sherratt M, Watson R, Graham H, Trafford A, Mummery P, Derby B. Nanoindentation of histological specimens: Mapping the elastic properties of soft tissues. JOURNAL OF MATERIALS RESEARCH 2009; 24:638-646. [PMID: 20396607 PMCID: PMC2854807 DOI: 10.1557/jmr.2009.0130] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
Although alterations in the gross mechanical properties of dynamic and compliant tissues have a major impact on human health and morbidity, there are no well-established techniques to characterize the micromechanical properties of tissues such as blood vessels and lungs. We have used nanoindentation to spatially map the micromechanical properties of 5-mum-thick sections of ferret aorta and vena cava and to relate these mechanical properties to the histological distribution of fluorescent elastic fibers. To decouple the effect of the glass substrate on our analysis of the nanoindentation data, we have used the extended Oliver and Pharr method. The elastic modulus of the aorta decreased progressively from 35 MPa in the adventitial (outermost) layer to 8 MPa at the intimal (innermost) layer. In contrast, the vena cava was relatively stiff, with an elastic modulus >30 MPa in both the extracellular matrix-rich adventitial and intimal regions of the vessel. The central, highly cellularized, medial layer of the vena cava, however, had an invariant elastic modulus of ~20 MPa. In extracellular matrix-rich regions of the tissue, the elastic modulus, as determined by nanoindentation, was inversely correlated with elastic fiber density. Thus, we show it is possible to distinguish and spatially resolve differences in the micromechanical properties of large arteries and veins, which are related to the tissue microstructure.
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Affiliation(s)
- R. Akhtar
- Address all correspondence to this author. e-mail:
| | - N. Schwarzer
- Saxonian Institute of Surface Mechanics (SIO), Ummanz 18569, Germany
| | - M.J. Sherratt
- Tissue Injury and Repair Group, Faculty of Medical and Human Sciences, University of Manchester, Manchester M13 9PT, United Kingdom
| | - R.E.B. Watson
- Dermatological Sciences Research Group, Faculty of Medical and Human Sciences, University of Manchester, Manchester M13 9PT, United Kingdom
| | - H.K. Graham
- Unit of Cardiac Physiology, Division of Cardiovascular and Endocrine Sciences, University of Manchester, Manchester M13 9NT, United Kingdom
| | - A.W. Trafford
- Unit of Cardiac Physiology, Division of Cardiovascular and Endocrine Sciences, University of Manchester, Manchester M13 9NT, United Kingdom
| | - P.M. Mummery
- School of Materials, University of Manchester, Manchester M1 7HS, United Kingdom
| | - B. Derby
- School of Materials, University of Manchester, Manchester M1 7HS, United Kingdom
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Miao H, Gracewski SM, Dalecki D. Ultrasonic excitation of a bubble inside a deformable tube: implications for ultrasonically induced hemorrhage. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2008; 124:2374-84. [PMID: 19062875 PMCID: PMC2677346 DOI: 10.1121/1.2967488] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Various independent investigations indicate that the presence of microbubbles within blood vessels may increase the likelihood of ultrasound-induced hemorrhage. To explore potential damage mechanisms, an axisymmetric coupled finite element and boundary element code was developed and employed to simulate the response of an acoustically excited bubble centered within a deformable tube. As expected, the tube mitigates the expansion of the bubble. The maximum tube dilation and maximum hoop stress were found to occur well before the bubble reached its maximum radius. Therefore, it is not likely that the expanding low pressure bubble pushes the tube wall outward. Instead, simulation results indicate that the tensile portion of the acoustic excitation plays a major role in tube dilation and thus tube rupture. The effects of tube dimensions (tube wall thickness 1-5 microm), material properties (Young's modulus 1-10 MPa), ultrasound frequency (1-10 MHz), and pressure amplitude (0.2-1.0 MPa) on bubble response and tube dilation were investigated. As the tube thickness, tube radius, and acoustic frequency decreased, the maximum hoop stress increased, indicating a higher potential for tube rupture and hemorrhage.
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Affiliation(s)
- Hongyu Miao
- Mechanical Engineering, University of Rochester, Rochester, New York 14627, USA
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Rezakhaniha R, Stergiopulos N. A structural model of the venous wall considering elastin anisotropy. J Biomech Eng 2008; 130:031017. [PMID: 18532866 DOI: 10.1115/1.2907749] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The three-dimensional biomechanical behavior of the vascular wall is best described by means of strain energy functions. Significant effort has been devoted lately in the development of structure-based models of the vascular wall, which account for the individual contribution of each major structural component (elastin, collagen, and vascular smooth muscle). However, none of the currently proposed structural models succeeded in simultaneously and accurately describing both the pressure-radius and pressure-longitudinal force curves. We have hypothesized that shortcomings of the current models are, in part, due to unaccounted anisotropic properties of elastin. We extended our previously developed biomechanical model to account for elastin anisotropy. The experimental data were obtained from inflation-extension tests on facial veins of five young white New Zealand rabbits. Tests have been carried out under a fully relaxed state of smooth muscle cells for longitudinal stretch ratios ranging from 100% to 130% of the in vivo length. The experimental data (pressure-radius, pressure-force, and zero-stress-state geometries) provided a complete biaxial mechanical characterization of rabbit facial vein and served as the basis for validating the applicability and accuracy of the new biomechanical model of the venous wall. When only the pressure-radius curves were fitted, both the anisotropic and the isotropic models gave excellent results. However, when both pressure-radius and pressure-force curves are simultaneously fitted, the model with isotropic elastin shows an average weighted residual sum of squares of 8.94 and 23.9 in the outer radius and axial force, respectively, as compared to averages of 6.07 and 4.00, when anisotropic elastin is considered. Both the Alkaike information criterion and Schwartz criterion show that the model with the anisotropic elastin is more successful in predicting the data for a wide range of longitudinal stretch ratios. We conclude that anisotropic description of elastin is required for a full 3D characterization of the biomechanics of the venous wall.
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Affiliation(s)
- Rana Rezakhaniha
- Hemodynamics and Cardiovascular Technology Laboratory (LHTC), School of Life Sciences, Institute of Bioengineering, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland.
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Akbari H, Kosugi Y, Kihara K. A novel method for artery detection in laparoscopic surgery. Surg Endosc 2007; 22:1672-7. [DOI: 10.1007/s00464-007-9688-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2007] [Accepted: 10/16/2007] [Indexed: 11/24/2022]
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