Red cell aggregation in blood flow

Schmid‐Schönbein, H.; Gallasch, G; Gosen, J. v.; Volger, E; Klose, Holger

doi:10.1007/bf01468880

Cited by 24 publications

(3 citation statements)

References 21 publications

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“…Viscometer measurements can take up to one minute to perform and in that time red cell aggregation and sedimentation occurs causing in- accurate readings. , 6,38 In addition, extrapolation of viscosity readings from a viscometer in vitro to the cerebral microcirculation may be inaccurate because viscosity will vary from one locus to another within the circulation depending upon the regional flow rate. These difficulties with viscometer measurements make it useful to develop a mathematical approximation of viscosity based on easily measured viscosity determinants such as serum fibrinogen and hematocrit.…”

Section: Resultsmentioning

confidence: 99%

Whole blood viscosity parameters and cerebral blood flow.

Grotta¹,

Ackerman²,

Correia³

et al. 1982

Stroke

211

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SUMMARY This report describes the statistical relationship of several whole blood viscosity parameters and cerebral blood flow (CBF) in 53 consecutive patients and normal controls. Significant correlations were present between CBF and serum fibrinogen (P = .05), hematocrit (P < .05), and a relationship involving both fibrinogen and hematocrit (P < .01).We conclude that heightened whole blood viscosity does correlate with decreased cerebral blood flow in the ranges measured in our patients, that both fibrinogen and hematocrit must be taken into consideration in viscosity determinations, and that changes in viscosity may have an important effect on CBF in regions of low flow.

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Section: Resultsmentioning

confidence: 99%

Whole blood viscosity parameters and cerebral blood flow.

Grotta¹,

Ackerman²,

Correia³

et al. 1982

Stroke

211

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show abstract

“…At low shear rates blood viscosity increases due to the formation of erythrocytes aggregation which starting as rouleaux and may be formed network shape under certain pathological conditions. At High shear rates blood, becomes less viscose due to lower a chance of erythrocytes to adhere with each other (Dintenfas, 1971;Schmid-Schönbein, Gallasch, Gosen, Volger, & Klose, 1976). Cell-cell interaction under low shear rates is mediated by hydrodynamic force (Shiga et al, 1983).…”

Section: Resultsmentioning

confidence: 99%

Biomechanical and Physiological Conditions Influence Erythrocytes - Erythrocyte Adhesion. An in vitro Study

Elblbesy¹

2017

APR

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Erythrocyte -erythrocyte adhesion (EEA) is of the large interest since it will effect directly on its function and interaction with other organs. Also, erythrocytes adhesion may arise erythrocytes aggregation which has a significant effect on the hemodynamic mechanism. The present study is aimed at examining the effect of erythrocytes mechanical properties on their adhesion. In addition, the impact of the physiological conditions around erythrocytes on their adhesion will be evaluated. A simple flow compartment technique built on inverted microscope was used to calculate adhesion number (AN) of erythrocytes which reflects the ability of erythrocytes to adhere to each other. AN was correlated strongly to shear rate and erythrocyte deformation index. Shape parameters of erythrocytes (Radius and volume) were found to play a major role in EEA. The concentration of the main plasma proteins (fibrinogen and albumin) were determined to have a significant effect on EEA. The results obtained in this study give the attention that other factors rather than particle diameter and work of adhesion may effect on erythrocytes adhesion.

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“… 40 An a posteriori analysis of results from P1-OUT revealed up to 100, 99 and of the total blood volume was exposed to a shear rate above 10, 100 and 250 s −1 , respectively, at some stage during a single pulse, with analogous figures of 100, 98 and respectively, obtained for P2-OUT. These significant exposures to high shear, at some stage during a single pulse, suggest widespread suppression of rouleaux formation, which is responsible for shear-thinning and occurs on a time-scale of order 1 s. 51 Consequently, the assumption of Newtonian rheology is considered reasonable. We also note that the assumption has been widely used in previous studies of blood flow in AVF and vascular grafts.…”

Section: Methodsmentioning

confidence: 99%

The Effect of Arterial Curvature on Blood Flow in Arterio-Venous Fistulae: Realistic Geometries and Pulsatile Flow

Grechy

Iori

Corbett

et al. 2017

Cardiovasc Eng Tech

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Arterio-Venous Fistulae (AVF) are regarded as the “gold standard” method of vascular access for patients with End-Stage Renal Disease (ESRD) who require haemodialysis. However, up to 60% of AVF do not mature, and hence fail, as a result of Intimal Hyperplasia (IH). Unphysiological flow and oxygen transport patterns, associated with the unnatural and often complex geometries of AVF, are believed to be implicated in the development of IH. Previous studies have investigated the effect of arterial curvature on blood flow in AVF using idealized planar AVF configurations and non-pulsatile inflow conditions. The present study takes an important step forwards by extending this work to more realistic non-planar brachiocephalic AVF configurations with pulsatile inflow conditions. Results show that forming an AVF by connecting a vein onto the outer curvature of an arterial bend does not, necessarily, suppress unsteady flow in the artery. This finding is converse to results from a previous more idealized study. However, results also show that forming an AVF by connecting a vein onto the inner curvature of an arterial bend can suppress exposure to regions of low wall shear stress and hypoxia in the artery. This finding is in agreement with results from a previous more idealized study. Finally, results show that forming an AVF by connecting a vein onto the inner curvature of an arterial bend can significantly reduce exposure to high WSS in the vein. The results are important, as they demonstrate that in realistic scenarios arterial curvature can be leveraged to reduce exposure to excessively low/high levels of WSS and regions of hypoxia in AVF. This may in turn reduce rates of IH and hence AVF failure.

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Red cell aggregation in blood flow

Cited by 24 publications

References 21 publications

Whole blood viscosity parameters and cerebral blood flow.

Whole blood viscosity parameters and cerebral blood flow.

Biomechanical and Physiological Conditions Influence Erythrocytes - Erythrocyte Adhesion. An in vitro Study

The Effect of Arterial Curvature on Blood Flow in Arterio-Venous Fistulae: Realistic Geometries and Pulsatile Flow

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