Non-Newtonian and flow pulsatility effects in simulation models of a stented intracranial aneurysm

Cavazzuti, Marco; Atherton, Mark; Collins, M. W.; Barozzi, Giovanni Sebastiano

doi:10.1177/09544119jeim894

Cited by 18 publications

(24 citation statements)

References 25 publications

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“…Furthermore, Cavazzuti et al [10] reported that a critical value of 0.5 Pa exists, below which thrombus formation may influence aneurysm rupture.…”

Section: Introductionmentioning

confidence: 98%

“…They compared observations from particle image velocimetry and MRI to those predicted by CFD, concluding that CFD is an acceptable predictor of complex flow patterns. Cavazzuti et al [10] investigated non-Newtonian flow within a side-wall intracranial aneurysm with reference to stent design, and concluded that non-Newtonian properties are important to avoid underestimating WSS. This directly contradicts the textbook advice to assume Newtonian viscosity [9,11,12].…”

Section: Introductionmentioning

confidence: 98%

“…Therefore, computational fluid dynamics (CFD) has been extensively used in the study of intracranial aneurysms [2,5,10,24]. Patient-specific CFD studies are increasingly being used to identify patients at risk of rupture [25].…”

Section: Introductionmentioning

confidence: 99%

“…Aneurysms are enlargements of the arterial walls [3] that form particularly at bends or bifurcations of blood vessels [5]. It is often assumed that for large blood vessels, the non-Newtonian effects of blood flow are negligible [6][7][8][9][10][11], and it has been stated that non-Newtonian viscosity can be ignored for vessels wider than 0.5 mm [12]. A number of factors, including hematocrit, plasma viscosity, vascular diameter, and temperature, have been determined to affect blood viscosity [13][14][15].…”

Section: Introductionmentioning

confidence: 99%

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Modeling Blood Flow Through Intracranial Aneurysms: A Comparison of Newtonian and Non-Newtonian Viscosity

2016

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The effect of non-Newtonian blood flow on the value of wall shear stress (WSS) of an intracranial aneurysm was investigated using computational fluid dynamics. For cerebral arteries, blood is often assumed to behave as a Newtonian fluid, though the effects of non-Newtonian flow on the prediction of areas of low WSS associated with aneurysm rupture are not clear. Geometry was based on published data and a Newtonian model validated against experimental results. Newtonian, unrestricted non-Newtonian, and viscosity-limited non-Newtonian models were compared under pulsatile conditions. Peak WSS of the Newtonian model was 28.7 Pa, and the lowest value of peak WSS for the unrestricted non-Newtonian models was 16.5 Pa. Viscosity-limited non-Newtonian models predicted flow velocity and WSS similar to those predicted by the Newtonian model in high-shear-rate regions, though maximum areas of critically low WSS were up to 42 % smaller than those predicted by the Newtonian model. In conclusion, viscosity limits are required to prevent excessive thinning of non-Newtonian models and the effects of non-Newtonian viscosity are significant for blood flow within low-shear-rate regions of an intracranial aneurysm.

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“…Furthermore, Cavazzuti et al [10] reported that a critical value of 0.5 Pa exists, below which thrombus formation may influence aneurysm rupture.…”

Section: Introductionmentioning

confidence: 98%

Section: Introductionmentioning

confidence: 98%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Modeling Blood Flow Through Intracranial Aneurysms: A Comparison of Newtonian and Non-Newtonian Viscosity

2016

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“…These studies have been performed both in healthy vasculature [6][7][8] and in the presence of aneurysms [9][10][11]. In particular, authors pay special attention to the influence of the choice of rheology model on the computational estimates of wall shear stress (WSS) as a proxy for aneurysm rupture risk.…”

Section: Introductionmentioning

confidence: 99%

Impact of blood rheology on wall shear stress in a model of the middle cerebral artery

et al. 2013

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One contribution of 25 to a Theme Issue 'The virtual physiological human: integrative approaches to computational biomedicine'. Perturbations to the homeostatic distribution of mechanical forces exerted by blood on the endothelial layer have been correlated with vascular pathologies, including intracranial aneurysms and atherosclerosis. Recent computational work suggests that, in order to correctly characterize such forces, the shear-thinning properties of blood must be taken into account. To the best of our knowledge, these findings have never been compared against experimentally observed pathological thresholds. In this work, we apply the three-band diagram (TBD) analysis due to Gizzi et al. (Gizzi et al. 2011 Three-band decomposition analysis of wall shear stress in pulsatile flows. Phys. Rev. E 83, 031902. (doi:10. 1103/PhysRevE.83.031902)) to assess the impact of the choice of blood rheology model on a computational model of the right middle cerebral artery. Our results show that, in the model under study, the differences between the wall shear stress predicted by a Newtonian model and the well-known Carreau-Yasuda generalized Newtonian model are only significant if the vascular pathology under study is associated with a pathological threshold in the range 0.94-1.56 Pa, where the results of the TBD analysis of the rheology models considered differs. Otherwise, we observe no significant differences.

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Optimization of porous stents for endovascular repair of abdominal aortic aneurysms

Stockle

Romero

Amón

2020

Numer Methods Biomed Eng

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This study presents a simulation‐based methodology to design porous stents to induce suitable hemodynamic environments inside abdominal aortic aneurysm (AAA) sacs. In the proposed methodology, an optimization algorithm iteratively modifies the porosity distribution of the stent and executes a computational fluid dynamics (CFD) simulation to determine the effect of these changes on the hemodynamic conditions inside the aneurysm sac. The optimization iterations proceed until relevant hemodynamic parameters are within ranges prescribed a priori by the user as desirable to control the progression of the AAA. The resulting porosity distribution uniquely describes the porous stent design that can control the hemodynamic environment (eg, shear stress at the aneurysm wall, pressure distribution, residence time), reducing AAA rupture risks and improving treatment efficacy. To demonstrate its potential, the proposed methodology is applied to idealized AAA geometry under steady‐state flow conditions, though it may be easily applied to more complex AAA geometries under transient, pulsatile flow conditions. The proposed methodology has the potential to enable the design of a new generation of porous stents tailored to patient‐specific geometries and flow conditions, to improve patient outcomes.

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Non-Newtonian and flow pulsatility effects in simulation models of a stented intracranial aneurysm

Cited by 18 publications

References 25 publications

Modeling Blood Flow Through Intracranial Aneurysms: A Comparison of Newtonian and Non-Newtonian Viscosity

Modeling Blood Flow Through Intracranial Aneurysms: A Comparison of Newtonian and Non-Newtonian Viscosity

Impact of blood rheology on wall shear stress in a model of the middle cerebral artery

Optimization of porous stents for endovascular repair of abdominal aortic aneurysms

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