Direct simulation of blood flow with heterogeneous cell suspensions in a patient-specific capillary network

Three-dimensional (3D) simulations on blood flow in a complex patient-specific retina vascular network were performed considering deformable red blood cells, white blood cells (WBCs), and obstructed vessels. First, the impact of blockage on flow rate distribution (without cells) was investigated. It showed that the blockage might change the flow rate significantly on distant vessels that were not directly connected with the blocked vessel. The flow rate in some vessels could increase up to 1200% due to an obstruction. However, with cells, it showed a fluctuating flow pattern, and the cells showed complicated transport behavior at bifurcations. Cell accumulation might occur in some bifurcations such as a T-shaped junction that eventually led to a physical blockage. The addition of WBCs impacted the local flow rate when they were squeezed through a capillary vessel, and the flow rate could be decreased up to 32% due to the larger size of WBCs. The simulation of flow under stenosis with cells showed that cells could oscillate and become trapped in a vessel due to the fluctuating flow. Finally, a reduced order model (ROM) with multiple non-Newtonian viscosity models was used to simulate the blood flow in the network. Compared with the 3D model, all ROMs reproduced accurate predictions on hematocrit and flow rate distribution in the vascular network. Among them, the Fahr & UAELIG;us-Lindqvist model was found to be the most accurate one. The work can be used to build a multiscale model for blood flow through integration of ROMs and 3D multiphysics models.Published under an exclusive license by AIP Publishing.

Automated summary

This study performs three-dimensional simulations on blood flow in a complex patient-specific retina vascular network, considering deformable red blood cells, white blood cells, and obstructed vessels. The results show that blockages can significantly alter flow rates in distant vessels. Cells exhibit a fluctuating flow pattern and can accumulate at bifurcations, leading to physical blockages. The addition of white blood cells decreases local flow rates. A reduced order model accurately predicts hematocrit and flow rate distribution, with the Fahr & UAELIG;us-Lindqvist model being the most accurate.