On the creation of wall shear stress by helical flow structures in stented coronary vessels

Abstract

AbstractThe post-operative situation in a stented vessel is characterised by struts which extend into the vessel lumen. These barriers on the surface provoke a topological change of the blood flow inducing flow deceleration and stagnation zones. Low values of wall shear stress (WSS) especially up- and downstream of the struts are found accordingly. Clinical studies correlate the occurrence of complications like restenosis and thrombosis with the alteration of the spatial WSS distribution. In this study 3D computational models were used to characterise the flow topology of three different stent types. For this purpose steady state simulations of the flow field within a simplified stented coronary artery were performed. The stent types differ in their strut patterns so that the variation of the induced flow structures can be observed. The aim of these investigations is to evaluate the effect of a purposeful flow control by altering the design of the struts. An improved alignment of the struts will be able to guide the flow to benefit the spatial WSS distribution. To compare the performance of the different stent types the size of the area charged with a WSS value below 0.5 Pa is used as a criterion. We will demonstrate that those strut pattern which generate helical flow structures significantly reduce the critical region of low WSS values.