A micro-scale simulation of red blood cell passage through symmetric and asymmetric bifurcated vessels

TL;DR

This study uses two-dimensional simulations to analyze how red blood cells deform and migrate in microvessels with bifurcations, revealing effects of cell shape, deformability, and hematocrit on blood flow behavior.

Contribution

It introduces a detailed simulation model incorporating fluid dynamics and membrane mechanics to study microvascular blood flow with bifurcations, highlighting factors affecting cell distribution and flow.

Findings

Red blood cells tend to enter the higher flow rate branch disproportionately.

Lateral migration and blunted velocity profiles are observed in microvessels.

A cell-free region forms around the confluence tip.

Abstract

Blood exhibits a heterogeneous nature of hematocrit, velocity, and effective viscosity in microcapillaries. Microvascular bifurcations have a significant influence on the distribution of the blood cells and blood flow behavior. This paper presents a simulation study performed on the two-dimensionalmotions and deformation of multiple red blood cells in microvessels with diverging and converging bifurcations. Fluid dynamics and membrane mechanics were incorporated. Effects of cell shape, hematocrit, and deformability of the cell membrane on rheological behavior of the red blood cells and the hemodynamics have been investigated. It was shown that the blood entering the daughter branch with a higher flow rate tended to receive disproportionally more cells. The results also demonstrate that red blood cells in microvessels experienced lateral migration in the parent channel and blunted velocity profiles in both straight section and daughter branches, and this effect was influenced by the shape and the initial position of the cells, the hematocrit, and the membrane deformability. In addition, a cell free region around the tip of the confluence was observed. The simulation results are qualitatively consistent with existing experimental findings. This study may provide fundamental knowledge for a better understanding of hemodynamic behavior of micro-scale blood flow.