N. Antonova 1, X. Dong 2, P. Tosheva 1, E. Kaliviotis 3, I. Velcheva 4
1 Department of Biomechanics, Institute of Mechanics, Bulgarian Academy of Sciences – Sofia, Bulgaria,
2 School of Civil Engineering, Tianjin University – Tianjin, China,
3 Division of Engineering, King's College – London, UK,
4 Department of Neurology, University Hospital of Neurology and Psychiatry “St. Naum”, Medical University – Sofia, Bulgaria

Objective: The aim of the study is to perform 3D numerical analysis of blood flow in the carotid artery bifurcation with and without stenoses.

Material and Methods: The analysis is based on the numerical simulation of Navier-Stokes equations. Four cases of carotid bifurcation are considered: common carotid artery (CCA) bifurcation without stenoses, with one, two and three stenoses are presented too. The analysis is performed considering one pulse wave period and it is based on the finite volume discretization of the Navier-Stokes equations.

Results: The structures of the flow around the bifurcation from CCA to the internal (ICA) and external carotid artery (ECA) are obtained considering characteristic time points for one pulse wave period. The axial velocity distribution and wall shear stress (WSS) distribution and contours are presented. The results manifest unsteady blood flow in the carotid bifurcation and dependence of the flow disturbances on the time and type of the stenoses. The recirculation zone behind the stenosis is the area of low WSS. Comparison of the peak WSS for the four different cases shows that it reaches the maximum value of about 6.7Pa at the characteristic point of T=0,2s for the cases with two and three stenoses.

Discussion: The obtained distribution of the WSS around the bifurcation allows a prediction of the probable sites of stenosis growth. The use of imaging investigation with mapping of WSS distribution in the carotid arteries in parallel with numerical analysis could help to demonstrate the risks of embolism or plaque rupture posed by particular plaque deposits.

Key words: blood flow 3D numerical analysis, carotid bifurcation, stenosis, wall shear stress.