Rapidly recovered transient flow resistance: a newly discovered property of blood

McMillan, D. E.; Strigberger, J.; Utterback, N. G.

doi:10.1152/ajpheart.1987.253.4.h919

Cited by 14 publications

(48 citation statements)

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“…If the 3-D models were obtained from real patient data, this would ultimately enable a treatment simulation and a more rational therapeutic decision. Finally, thixotropic effects (the initial extra flow resistance linked to developing orientation and disaggregation of erythrocytes) should be experimentally analyzed and incorporated into flow simulations, to obtain an even more detailed and realistic impression of blood flow behavior [18].…”

Section: Discussionmentioning

confidence: 99%

Rheological Changes After Stenting of a Cerebral Aneurysm: A Finite Element Modeling Approach

Ohta

Wetzel

Dantan

et al. 2005

Cardiovasc Intervent Radiol

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Hemodynamic changes in intracranial aneurysms after stent placement include the appearance of areas with stagnant flow and low shear rates. We investigated the influence of stent placement on blood flow velocity and wall shear stress of an intracranial aneurysm using a finite element modeling approach. To assess viscosity changes induced by stent placement, the rheology of blood as non-Newtonian fluid was taken into account in this model. A two-dimensional model with a parent artery, a smaller branching artery, and an aneurysm located at the bifurcation, before and after stent placement, was used for simulation. Flow velocity plots and wall shear stress before and after stent placement was calculated over the entire cardiac circle. Values for dynamic viscosity were calculated with a constitutive equation that was based on experimental studies and yielded a viscosity, which decreases as the shear rate increases. Stent placement lowered peak velocities in the main vortex of the aneurysm by a factor of at least 4 compared to peak velocities in the main artery, and it considerably decreased the wall shear stress of the aneurysm. Dynamic viscosity increases after stent placement persisted over a major part of the cardiac cycle, with a factor of up to 10, most pronounced near the dome of the aneurysm. Finite element modeling can offer insight into rheological changes induced by stent treatment of aneurysms and allows visualizing dynamic viscosity changes induced by stent placement.

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Section: Discussionmentioning

confidence: 99%

Rheological Changes After Stenting of a Cerebral Aneurysm: A Finite Element Modeling Approach

Ohta

Wetzel

Dantan

et al. 2005

Cardiovasc Intervent Radiol

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“…We offer a consistent TEVP constitutive model that encompasses the most crucial characteristics of the aforementioned blood properties in order to validate experimental results satisfactorily and provide accurate predictions for steady-state flow regimes in microchannels. Our model is shown to produce results that agree well both with steady state and transient blood flow data [47]. Apart from the integrated modeling of blood rheological complexity, our implementation is adequate for multi-dimensional simulations due to its tensorial formalism, contrary to recent investigations of blood flow [57], which do not offer a tensorial form of their model.…”

Section: Introductionmentioning

confidence: 74%

“…The available experimental data in the literature are limited to those reported in the works of McMillan et al [47], Armstrong et al [48] and Bureau et al [46], which were restricted to a small range of hemodynamical properties eliminating the opportunity of making a parametric correlation between the model's features and fundamental macroscopic properties such as fibrinogen or hematocrit. Primarily, we use the experiments conducted by McMillan et al [47] for a healthy subject of systemic hematocrit equal to 45%. The steady-state experiment refers to simple shear flow data providing the shear stress response as a function of the imposed shear rate.…”

Section: Rheological Data Fitting and Calculation Of The Model Paramementioning

confidence: 99%

“…One of the prominent experimental investigations is that of Bureau et al [46] who systematically obtained hysteresis and step-up curves of pathological and physiological human blood. Here, we invoke the experimental work of McMillan et al [47], who performed steady-state shear and rectangular shear-step tests which are capable to probe the elasto-thixotropic response of blood making our model robust and reliable. More recently, Armstrong et al [48] and Horner et al [49] conducted experiments in steady and transient rheometric flows.…”

Section: Introductionmentioning

confidence: 98%

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Advanced Constitutive Modeling of the Thixotropic Elasto-Visco-Plastic Behavior of Blood: Description of the Model and Rheological Predictions

et al. 2020

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This work focuses on the advanced modeling of the thixotropic nature of blood, coupled with an elasto-visco-plastic formulation by invoking a consistent and validated model for TEVP materials. The proposed model has been verified for the adequate description of the rheological behavior of suspensions, introducing a scalar variable that describes dynamically the level of internal microstructure of rouleaux at any instance, capturing accurately the aggregation and disaggregation mechanisms of the RBCs. Also, a non-linear fitting is adopted for the definition of the model’s parameters on limited available experimental data of steady and transient rheometric flows of blood samples. We present the predictability of the new model in various steady and transient rheometric flows, including startup shear, rectangular shear steps, shear cessation, triangular shear steps and LAOS tests. Our model provides predictions for the elasto-thixotropic mechanism in startup shear flows, demonstrating a non-monotonic relationship of the thixotropic index on the shear-rate. The intermittent shear step test reveals the dynamics of the structural reconstruction, which in turn is associated with the aggregation process. Moreover, our model offers robust predictions for less examined tests such as uniaxial elongation, in which normal stress was found to have considerable contribution. Apart from the integrated modeling of blood rheological complexity, our implementation is adequate for multi-dimensional simulations due to its tensorial formalism accomplished with a single time scale for the thixotropic effects, resulting in a low computational cost compared to other TEVP models.

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“…It should be noted that measurements of the viscosity of blood in vivo give rheological parameters differing from those measured using a viscosimeter (in vitro). This is explained by the fact that stationary measurement methods that are usually used for measuring blood in vitro give no way of exactly determining its rheological properties; more reliable data on these properties can be obtained using a nonstationary measurement method that reproduces the actual conditions more adequately [4].…”

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confidence: 99%

Determination of the rheological properties of whole blood by the nonstationary method of pulsed changing of the rate of shear

Shul’man

Mansurov

2005

J Eng Phys Thermophys

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612.13Problems associated with the use of the nonstationary method of pulsed changing of the rate of shear for the measurement of important viscoplastic properties of whole blood -the critical shear stress τ 0 and the plastic viscosity µ p -are considered. The indicated method was compared to the method of stationary rheometry. It is shown that the blood-flow curve obtained by this method, unlike that obtained by the stationary method, characterizes a viscoplastic medium. To calculate the parameters of this medium exactly, it is necessary to take into account the dependence of the rate of shear on the above-indicated parameters.The study of the rheological properties of whole blood, considered as a macroscopic system, and the relation between these properties and other parameters is of considerable importance in the solution of important medical problems. By way of example we refer to the pathological processes in an organism that significantly influence the rheological properties of the blood and plasma and, as a result, cause the so-called hemorheological disturbances. These disturbances manifest themselves markedly in the case of cardiovascular diseases, such as myocardial ischemia, diabetes, and sepsis, and in the case of long physical loads [1,2].An increase in the blood viscosity, caused by a decrease in the deformability and the aggregation ability of erythrocytes, is typical of the majority of cardiovascular diseases. The ischemic diseases of other organs are also accompanied by a deterioration of the hemorheological parameters. In the case of certain diseases, these changes can be considered as an indication of an insufficiency of the circulatory functions and, therefore, can be used for diagnostic purposes [2].It is difficult to investigate blood circulation experimentally because, in this case, the measuring methods influence the investigation object. This is explained by the fact that, along with the problems associated with the complex hydrodynamics of the flow in rheometers, there arise problems caused by the physicochemical processes in colloidal systems. For example, some experimental schemes give no way of taking into account the nonstationary processes occurring in the blood flow in an organism [2].Evidently, the classical notion of the viscosity of liquids as their constant coefficient of internal friction loses its meaning for microdisperse liquids. The rheological properties of these liquids can be characterized by the consistency measured under viscosimetry conditions. This characteristic is a function of the shear viscosity and is determined from the relation between the rate of shear γ . and the shear stress τ. The odd material function τ = τ(γ . ) or γ . = γ .(τ), i.e., the viscosity function, should be reproducible under the conditions of any viscosimetry experiment and, consequently, should define any rheological property of a given microdisperse liquid at a definite temperature, pressure, and aggregate dispersion state. In this case, in the majority of publications devoted to the rheom...

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Rapidly recovered transient flow resistance: a newly discovered property of blood

Cited by 14 publications

References 0 publications

Rheological Changes After Stenting of a Cerebral Aneurysm: A Finite Element Modeling Approach

Rheological Changes After Stenting of a Cerebral Aneurysm: A Finite Element Modeling Approach

Advanced Constitutive Modeling of the Thixotropic Elasto-Visco-Plastic Behavior of Blood: Description of the Model and Rheological Predictions

Determination of the rheological properties of whole blood by the nonstationary method of pulsed changing of the rate of shear

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