Modeling Viscoelastic Wall Properties of Ovine Arteries

Author(s):  
Daniela Valdez-Jasso ◽  
Mansoor A. Haider ◽  
Stephen L. Campbell ◽  
Daniel Bia ◽  
Yanina Zocalo ◽  
...  

Generation of a complete map of arterial wall mechanical properties can improve treatment of cardiovascular diseases via contributions to design of patient specific vascular substitutes used to alleviate atherosclerosis and stenoses, which are predominant in arterial pathways (i.e., abdominal aorta, carotids, or femoral arteries). Clinically useful estimation of arterial properties from patient data requires both efficient algorithms and models that are both complex enough to capture clinically important properties and simple enough to allow rapid computation. In this study, we used mechanical models accounting for both elastic and viscoelastic wall deformation to analyze how vessel properties and associated model parameters vary with artery type. It is known that for the aorta wall, deformation is dominated by nonlinear elastic dynamics, while for the smaller vessels (e.g. the carotid artery) deformation is dominated by viscoelastic responses. The latter is correlated with composition of the vessels; the aorta contains significantly less smooth muscle cells (∼40%) than the carotid artery (∼60%), and has significantly more elastin (see Fig 1).

2019 ◽  
Vol 35 (6) ◽  
pp. 901-914
Author(s):  
Saeed Siri ◽  
Malikeh Nabaei ◽  
Nasser Fatouraee

ABSTRACTShear induced autoregulation is the natural ability of organs to maintain the local hemodynamic stresses in a stable condition in spite of altering perfusion rate. Endothelium cells are shear sensitive mechanoreceptors that are responsible for regulating the arterial wall architecture and mechanical properties in order to maintain homeostasis. This occurs by means of vasoactive mediators, which cause vasodilation or vasoconstriction. In this paper we presented a multiscale model of local flow regulation. First, a lumped parameter model of the whole cardiovascular system was implemented. Then a 3D numerical model of human common carotid artery was constructed considering fluid-structure interaction. The CCA inflow waveform obtained from the extended 0D model was applied to the 3D model as the boundary condition. After applying the Head-Up Tilt test, the local hemodynamics were disturbed. By considering the wall shear stress as the regulation criterion, then altering the arterial mechanical properties and the following vasodilation, shear forces exerted on the inner lining of the vessel were regulated and returned to the normal range. The resulting 0D/3D model can be considered as a plat-form for a more complete model containing local and systemic cardiovascular control mechanisms and patient-specific geometries which can be used for clinical purposes.


2013 ◽  
Vol 05 (04) ◽  
pp. 1330002 ◽  
Author(s):  
Hadi Taghizadeh ◽  
Mohammad Tafazzoli Shadpour

Mechanical characteristics of soft biological tissues mostly depend on their hierarchy at different scales from nano- to macro-structure. It is shown that arterial wall tissue is highly sensitive to its mechanical environment and any alteration in mechanical factors such as blood pressure, triggers physio- pathological processes within arterial wall. Quantification of these mechanical properties will provide us with deeper insights of ongoing biological events. In this context, mechanical contributions of wall constituents in health and diseases are of growing interest. Hence, this review is concerned with mechanical models of arterial wall tissue with a focus on microstructurally motivated representations.


2000 ◽  
Vol 84 (5) ◽  
pp. 757-764 ◽  
Author(s):  
Pascal Laurant ◽  
Daniel Hayoz ◽  
Hans Brunner ◽  
Alain Berthelot

The purpose of the present study was to determine the effects of Mg deficiency and supplementation on the mechanical properties of the rat common carotid artery. The internal diameter and intra-arterial pressure of carotid artery were measured continuously using an echo-tracking device. Systolic, diastolic and mean intra-arterial pressures were not significantly different in Mg-deficient, -supplemented or control rats. Histological examination showed a larger cross-sectional area, increased intima-media thickness and a greater media:lumen value in carotid artery of Mg-deficient rats, indicating that Mg deficiency may directly stimulate growth and/or proliferation of arterial wall components. In addition, we observed a negative linear relationship between intima-media thickness and plasma Mg concentration, suggesting that increased Mg intake may counteract arterial wall hypertrophy. Neither Mg deficiency nor supplementation modified the arterial distensibilityv.intra-arterial pressure curve or the Eincv.wall stress curve, indicating that dietary Mg intake did not modify wall stiffness in young rats. At mean intra-arterial pressure, the stress and Eincvalues were, however, significantly lower in Mg-deficient rats (P<0·05 in both cases); this finding could be related to the alteration in the geometry of the carotid artery. In conclusion, these findings suggest that Mg deficiency modifies the mechanical properties of the common carotid artery in young rats. Since Mg deficiency is considered a risk factor, these mechanical alterations could contribute to the development of atherosclerosis, hypertension and cardiovascular diseases.


1969 ◽  
Vol 21 (01) ◽  
pp. 001-011 ◽  
Author(s):  
K Onoyama ◽  
K Tanaka

SummaryThe tissue fibrinolysis was studied in 550 specimens of 7 kinds of arteries from 80 fresh cadavers, using Astrup’s biochemical method and Todd’s histochemical method with human fibrinogen.In the microscopically normal aortic wall, almost all specimens had the fibrinolytic activity which was the strongest in the adventitia and the weakest in the media.The fibrinolytic activity seemed to be localized in the endothelium.The stronger activity lay in the adventitia of the aorta and the pulmonary artery and all layers of the cerebral artery.The activity of the intima and media of the macroscopically normal areas seemed to be stronger in the internal carotid artery than in the common carotid artery.Mean fibrinolytic activity of the macroscopically normal areas seemed to decrease with age in the intima and the media of the thoracic aorta and seemed to be low in the cases with a high atherosclerotic index.The fibrinolytic activities of all three layers of the fibrous thickened aorta seemed to decrease, and those of the media and the adventitia of the atheromatous plaque to increase.The fibrinolytic activity of the arterial wall might play some role in the progress of atherosclerosis.


2009 ◽  
Vol 1 (1) ◽  
pp. 41-49
Author(s):  
Marc Bosiers ◽  
Koen Deloose ◽  
Jurgen Verbist ◽  
Patrick Peeters

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Xueping Chen ◽  
Jian Zhuang ◽  
Huanlei Huang ◽  
Yueheng Wu

AbstractThe purpose of this study is to compare the effect of the different physical factors on low-density lipoproteins (LDL) accumulation from flowing blood to the arterial wall of the left coronary arteries. The three-dimensional (3D) computational model of the left coronary arterial tree is reconstructed from a patient-specific computed tomography angiography (CTA) image. The endothelium of the coronary artery is represented by a shear stress dependent three-pore model. Fluid–structure interaction ($$FSI$$ FSI ) based numerical method is used to study the LDL transport from vascular lumen into the arterial wall. The results show that the high elastic property of the arterial wall decreases the complexity of the local flow field in the coronary bifurcation system. The places of high levels of LDL uptake coincide with the regions of low wall shear stress. In addition, hypertension promotes LDL uptake from flowing blood in the arterial wall, while the thickened arterial wall decreases this process. The present computer strategy combining the methods of coronary CTA image 3D reconstruction, $$FSI$$ FSI simulation, and three-pore modeling was illustrated to be effective on the simulation of the distribution and the uptake of LDL. This may have great potential for the early prediction of the local atherosclerosis lesion in the human left coronary artery.


2019 ◽  
Vol 170 ◽  
pp. 95-106 ◽  
Author(s):  
Nathan Lauzeral ◽  
Domenico Borzacchiello ◽  
Michael Kugler ◽  
Daniel George ◽  
Yves Rémond ◽  
...  

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Dayeong Hong ◽  
HaeKang Kim ◽  
Taehun Kim ◽  
Yong-Hee Kim ◽  
Namkug Kim

AbstractHerein, realistic and reusable phantoms for simulation of pediatric lung video-assisted thoracoscopic surgery (VATS) were proposed and evaluated. 3D-printed phantoms for VATS were designed based on chest computed tomography (CT) data of a pediatric patient with esophageal atresia and tracheoesophageal fistula. Models reflecting the patient-specific structure were fabricated based on the CT images. Appropriate reusable design, realistic mechanical properties with various material types, and 3D printers (fused deposition modeling (FDM) and PolyJet printers) were used to represent the realistic anatomical structures. As a result, the phantom printed by PolyJet reflected closer mechanical properties than those of the FDM phantom. Accuracies (mean difference ± 95 confidence interval) of phantoms by FDM and PolyJet were 0.53 ± 0.46 and 0.98 ± 0.55 mm, respectively. Phantoms were used by surgeons for VATS training, which is considered more reflective of the clinical situation than the conventional simulation phantom. In conclusion, the patient-specific, realistic, and reusable VATS phantom provides a better understanding the complex anatomical structure of a patient and could be used as an educational phantom for esophageal structure replacement in VATS.


Author(s):  
Christopher J. Arthurs ◽  
Nan Xiao ◽  
Philippe Moireau ◽  
Tobias Schaeffter ◽  
C. Alberto Figueroa

AbstractA major challenge in constructing three dimensional patient specific hemodynamic models is the calibration of model parameters to match patient data on flow, pressure, wall motion, etc. acquired in the clinic. Current workflows are manual and time-consuming. This work presents a flexible computational framework for model parameter estimation in cardiovascular flows that relies on the following fundamental contributions. (i) A Reduced-Order Unscented Kalman Filter (ROUKF) model for data assimilation for wall material and simple lumped parameter network (LPN) boundary condition model parameters. (ii) A constrained least squares augmentation (ROUKF-CLS) for more complex LPNs. (iii) A “Netlist” implementation, supporting easy filtering of parameters in such complex LPNs. The ROUKF algorithm is demonstrated using non-invasive patient-specific data on anatomy, flow and pressure from a healthy volunteer. The ROUKF-CLS algorithm is demonstrated using synthetic data on a coronary LPN. The methods described in this paper have been implemented as part of the CRIMSON hemodynamics software package.


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