Fluid-structure interaction investigation of spiral flow in a model of abdominal aortic aneurysm

• Effect of spiral flow on haemodynamic changes in a model of abdominal aortic aneurysm (AAA) is investigated.
• An increase in the intensity of spiral flow results in an increase in the maximum wall shear stress (WSS) and a decrease in the size of regions with low WSS.
• Neglecting the effect of spiral flow in modeling of AAAs can underestimate the magnitude of WSS by up to 30% and overestimate the magnitude of wall stress by up to 11%.
• Spiral nature of blood flow within AAAs reduces the risk of rupture, endothelial dysfunction and the development of atherosclerosis.

The presence of a spiral arterial blood flow pattern in both animals and humans has been widely accepted. The effect of spiral flow on physiological processes associated with abdominal aortic aneurysm (AAA) development and progressions can provide valuable information. The purpose of this study is to investigate the influence of spiral flow on haemodynamic changes in an elastic AAA model by implementing a coupled fluid–structure interaction (FSI) analysis. The results showed that an increase in the intensity of spiral flow resulted in an increase in maximum wall shear stress (WSS) and a decrease in maximum wall stress; however, the spiral flow effect on the WSS was higher than the wall stress. It was also shown that not taking into consideration the effect of spiral flow in modelling of AAA can underestimate the magnitude of WSS by up to 30% and overestimate the magnitude of wall stress by up to 11%. The presence of spiral flow within AAAs is associated with beneficial and detrimental effects. The beneficial effects are to reduce the wall stress and the size of regions with low WSS which in turn reduce the risk of rupture, endothelial dysfunction and the development of atherosclerosis. However, the increase in magnitude of WSS is seen as the detrimental effect of spiral flow.