The Impact of Pulsatile Spiral Flow on the Wall Deformation Characteristics and Low-density Lipoproteins Accumulation in the Aorta

Abstract

Spiral blood flow in the aorta is helpful in maintaining the stability of flow, reduction in lateral forces, turbulence near walls, and shear stress index. Thus, it helps in the prevention of diseases, such as atherosclerosis and atherogenesis, in the aortic arch because of the reduced accumulation of low-density lipoproteins (LDLs). To investigate the actual physics behind the aforementioned phenomenon, we conducted a fluid-structure interaction (FSI)-based numerical simulation of the three-dimensional aortic arch model under the influence of a pulsatile spiral flow. Spiral flow was introduced through the use of a mapping methodology between a spiral graft model and aortic model. The physics of time dependent pulsatile spiral turbulent flow was coupled with the structural mechanics of the aorta by using the FSI method. Results showed that the exterior interface of the aortic arch tends to rupture under the actions of centrifugal forces and secondary flow counter-rotating vortices in addition to applied pressure forces. Under systolic and diastolic conditions, the interior and exterior interfaces of the aortic arch both had small displacement, thus showing the insignificant role of velocity gradients in wall deformation. Moreover, LDL accumulation in the aorta under the influence of pulsatile spiral flow has been investigated using particle tracing methodology. The LDLs were evenly distributed in the aorta because of the influence of spiral flow. This result shows that spiral flow can contribute to the elimination of threats from diseases, such as atherosclerosis and atherogenesis.

Keywords

• fluid structure interaction
• pulsatile-spiral flow
• aortic arch
• low density lipoproteins (ldls)
• particle tracing