Cardiovascular
Solid Mechanics: Cells, Tissues, and Organs

Humphrey, J. D.; Epstein, Marcelo

doi:10.1115/1.1497492

Cited by 674 publications

(1,213 citation statements)

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“…Further physiological relevance could also be achieved with biaxial loading, which more closely reflects the in vivo loading conditions [70,71,72]. However, there are practical difficulties associated with using biaxial testing at high loads present in this study [73], and doing so may yield poor estimates of stress [74,75].…”

Section: Limitationsmentioning

confidence: 97%

Creating a model of diseased artery damage and failure from healthy porcine aorta

Noble

Smulders

Green

et al. 2016

Journal of the Mechanical Behavior of Biomedical Materials

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Article available under the terms of the CC-BY-NC-ND licence (https://creativecommons.org/licenses/by-nc-nd/4.0/) eprints@whiterose.ac.uk https://eprints.whiterose.ac.uk/ Reuse Unless indicated otherwise, fulltext items are protected by copyright with all rights reserved. The copyright exception in section 29 of the Copyright, Designs and Patents Act 1988 allows the making of a single copy solely for the purpose of non-commercial research or private study within the limits of fair dealing. The publisher or other rights-holder may allow further reproduction and re-use of this version -refer to the White Rose Research Online record for this item. Where records identify the publisher as the copyright holder, users can verify any specific terms of use on the publisher's website. TakedownIf you consider content in White Rose Research Online to be in breach of UK law, please notify us by emailing eprints@whiterose.ac.uk including the URL of the record and the reason for the withdrawal request.Creating a model of diseased artery damage and failure from healthy porcine aorta AbstractLarge quantities of diseased tissue are required in the research and development of new generations of medical devices, for example for use in physical testing. However, these are difficult to obtain. In contrast, porcine arteries are readily available as they are regarded as waste. Therefore, reliable means of creating from porcine tissue physical models of diseased human tissue that emulate well the associated mechanical changes would be valuable. To this end, we studied the effect on mechanical response of treating porcine thoracic aorta with collagenase, elastase and glutaraldehyde. The alterations in mechanical and failure properties were assessed via uniaxial tension testing. A constitutive model composed of the Gasser-Ogden-Holzapfel model, for elastic response, and a continuum damage model, for the failure, was also employed to provide a further basis for comparison [1,2]. For the concentrations used here it was found that: collagenase treated samples showed decreased fracture stress in the axial direction only; elastase treated samples showed increased fracture stress in the circumferential direction only; and glutaraldehyde samples showed no change in either direction. With respect to the proposed constitutive model, both collagenase and elastase had a strong effect on the fibre-related terms. The model more closely captured the tissue response in the circumferential direction, due to the smoother and sharper transition from damage initiation to complete failure in this direction. Finally, comparison of the results with those of tensile tests on diseased tissues suggests these treatments indeed provide a basis for creation of physical models of diseased arteries.

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Section: Limitationsmentioning

confidence: 97%

Creating a model of diseased artery damage and failure from healthy porcine aorta

Noble

Smulders

Green

et al. 2016

Journal of the Mechanical Behavior of Biomedical Materials

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“…These three different stress tensors are interrelated through the fundamental measure of the deformation gradient and its determinant [30] , and in elastic materials they are all dependent on the deformation gradientF s [9;25] . In the derivation of constitutive equations in Section 2.7, both the Cauchy stress tensor σ s and the second Piola-Kirchhoff stress tensorŜ s take simple forms because of their symmetric property.…”

Section: Piola Transformationmentioning

confidence: 99%

“…For a solid, it is important to determine whether the behavior is elastic or not [30] , and many important aspects of the mechanical behavior of arterial tissue can be treated on the basis of elasticity theory [27] . If the considered material is elastic, the Cauchy stress tensor should only be dependent on the position x and the deformation gradient F s .…”

Section: Chemical Processesmentioning

confidence: 99%

Mathematical modeling and simulation of the evolution of plaques in blood vessels

et al. 2015

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The formation of plaques is one of the main causes for the blockage of arteries. This can lead to ischaemic brain or myocardial infarctions as well as other cardiovascular diseases. Possible biochemical and biomechanical processes contribute to the development of plaque growth and rupture. The main biochemical processes are the penetration of monocytes and the accumulation of foam cells in the vessel wall, leading to the formation and growth of plaques. The biomechanical forces can be measured by observing stresses in the blood flow and the vessel wall, which may lead to the rupture of plaques.In this thesis, we formulate an appropriate model to describe the evolution of plaques. The model consists of both the interaction between the blood flow and the vessel wall, and the growth of plaques due to the penetration of monocytes from the blood flow into the vessel wall. The Navier-Stokes equations and the elastic structure equations are used to describe the dynamics of fluid (blood flow) and the mechanics of structure (vessel wall). The motion of monocytes is described by the convection-diffusion-reaction equation, coupled with an equation for the accumulation of foam cells. Finally the metric of growth is introduced to accurately determine the stress tensor, and its evolution equation is derived. The variational formulation of the model is transformed into the ALE (Arbitrary Lagrangian-Eulerian) formulation, and all the equations are rewritten in the fixed domain. Temporal discretization is achieved with finite differences and spatial discretization is based on the Galerkin finite element method. The nonlinear systems are linearized and solved by the Newton method.Based on the model and the numerical methods above, numerical simulations are performed by using the software Gascoigne. The obtained numerical results make an agreement with the observation, and support the assumption that the penetration of monocytes and the accumulation of foam cells lead to the formation and growth of plaques, and that the evolution of plaques induces the increase of stresses in the vessel wall, which is an indicator of plaque rupture. Zusammenfassung

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“…Cerebral aneurysms are pathological dilatations of arteries occurring mainly at bifurcations located in the vicinity of the circle of Willis [1]. Under the effect of a single or a combination of factors, the arterial wall is progressively thinned and ballooned out to create an aneurysm.…”

Section: Introductionmentioning

confidence: 99%

“…Although yet to explore further, in our view the most promising method to alter the biology of the aneurysm wall is acting on the fluid mechanic parameters, such as blood pressure, flow rates and patterns that may all, individually or in combination, alter the biological response of the wall constituents or of the endothelium, which in turn releases bioactive substances regulating the metabolism and matrix turnover of the aneurismal wall [1]. If acting on the vessel lumen side to implement flow correction through medical devices like coils and stents seems increasingly feasible, acting on the outside of the aneurysm wall is less promising.…”

Section: Introductionmentioning

confidence: 99%

Methodologies to assess blood flow in cerebral aneurysms: Current state of research and perspectives

Augsburger

Reymond

Fonck

et al. 2009

Journal of Neuroradiology

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KEYWORDSCerebral aneurysms; Blood flow assessment; Particle image velocimetry; Computational fluid dynamics Summary With intracranial aneurysms disease bringing a weakened arterial wall segment to initiate, grow and potentially rupture an aneurysm, current understanding of vessel wall biology perceives the disease to follow the path of a dynamic evolution and increasingly recognizes blood flow as being one of the main stakeholders driving the process. Although currently mostly morphological information is used to decide on whether or not to treat a yet unruptured aneurysm, among other factors, knowledge of blood flow parameters may provide an advanced understanding of the mechanisms leading to further aneurismal growth and potential rupture. Flow patterns, velocities, pressure and their derived quantifications, such as shear and vorticity, are today accessible by direct measurements or can be calculated through computation. This paper reviews and puts into perspective current experimental methodologies and numerical approaches available for such purposes. In our view, the combination of current medical imaging standards, numerical simulation methods and endovascular treatment methods allow for thinking that flow conditions govern more than any other factor fate and treatment in cerebral aneurysms. Approaching aneurysms from this perspective improves understanding, and while requiring a personalized aneurysm management by flow assessment and flow correction, if indicated.

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Cardiovascular Solid Mechanics: Cells, Tissues, and Organs

Cited by 674 publications

References 0 publications

Creating a model of diseased artery damage and failure from healthy porcine aorta

Creating a model of diseased artery damage and failure from healthy porcine aorta

Mathematical modeling and simulation of the evolution of plaques in blood vessels

Methodologies to assess blood flow in cerebral aneurysms: Current state of research and perspectives

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