Influence of Geometric Parameters on the Hemodynamic Characteristics of the Vertebral Artery

The carotid arteries (CAs) and vertebral arteries (VAs) are principal conduits for cerebral blood supply and are common sites for atherosclerotic plaque formation. To date, there has been extensive clinical and hemodynamic reporting on carotid arteries; however, studies focusing on the hemodynamic characteristics of the VA are notably scarce. This article presents a systematic analysis of the impact of VA diameter and the angle of divergence from the subclavian artery (SA) on hemodynamic properties, facilitated by the construction of an idealized VA geometric model. Research indicates that the increase in the diameter of the VA is associated with a corresponding increase in the complexity of the vortex structures at the bifurcation with the SA. When the VA diameter is constant, a 30 deg VA-SA angle yields better hemodynamic capacity than 45 deg and 60 deg angles, and the patterns of blood flow and helicity values are consistent across different angles. Elevated oscillatory shear index (OSI) zones are mainly at the origin of the VA, with an elliptical low OSI region within. As the diameter increases, the high OSI region spreads downstream. Increasing the bifurcation angle decreases OSI values in and below the elliptical low OSI region. These findings are valuable for studying the physiological and pathological mechanisms of VA atherosclerosis.