Flow of Red Blood Cells in Stenosed Microvessels.

Koohyar Vahidkhah,Prosenjit Bagchi,Peter Balogh

doi:10.1038/srep28194

Koohyar Vahidkhah, Prosenjit Bagchi + Show 1 more

Open Access

https://doi.org/10.1038/srep28194

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Journal: Scientific Reports	Publication Date: Jun 20, 2016
Citations: 51	License type: CC BY 4.0

Affiliation: Rutgers, The State University of New Jersey

Abstract

A computational study is presented on the flow of deformable red blood cells in stenosed microvessels. It is observed that the Fahraeus-Lindqvist effect is significantly enhanced due to the presence of a stenosis. The apparent viscosity of blood is observed to increase by several folds when compared to non-stenosed vessels. An asymmetric distribution of the red blood cells, caused by geometric focusing in stenosed vessels, is observed to play a major role in the enhancement. The asymmetry in cell distribution also results in an asymmetry in average velocity and wall shear stress along the length of the stenosis. The discrete motion of the cells causes large time-dependent fluctuations in flow properties. The root-mean-square of flow rate fluctuations could be an order of magnitude higher than that in non-stenosed vessels. Several folds increase in Eulerian velocity fluctuation is also observed in the vicinity of the stenosis. Surprisingly, a transient flow reversal is observed upstream a stenosis but not downstream. The asymmetry and fluctuations in flow quantities and the flow reversal would not occur in absence of the cells. It is concluded that the flow physics and its physiological consequences are significantly different in micro- versus macrovascular stenosis.

Highlights

A computational study is presented on the flow of deformable red blood cells in stenosed microvessels
Research over the past several decades has established the important role of fluid flow in large vessel disease[2,3,4,5]
The resting biconcave shape is somewhat maintained at low flow rates, but not at high flow rates

Summary

Introduction

A computational study is presented on the flow of deformable red blood cells in stenosed microvessels. Illustrations of the cellular nature of blood flow in small vessels are the well known Fahraeus-Lindqvist and Fahraeus effects. The former refers to a reduction of the apparent blood viscosity with decreasing vessel diameter. Endothelial cells (ECs) lining the inner wall of blood vessels are known to respond to local hemodynamic conditions, such as the wall shear stress and flow oscillation. In small vessels, the motion of individual blood cell causes temporal and spatial variations leaving their ‘footprints’ on ECs31 Such temporal and spatial flow oscillations in stenosed microvessels have not been quantified in the literature. Studies using microfluidic conduits with severe constrictions showed greatly enhanced plasma and cell separation and increased downstream CFL thickness[16]

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