a b s t r a c tThis paper reviews the recent literature regarding the time-dependant computational fluid dynamics (CFD) analyses of blood flow through implanted coronary stents. The in vivo processes which result in arterial restenosis are identified. The definition and range of the computationally predicted variables which are believed to stimulate the restenosis processes are evaluated. The reviewed literature is subdivided into effect-based in which the effects of altering the flow model are investigated and designbased in which different geometric stent configurations are compared. Finally, conclusions are made regarding the body of work reviewed and recommendations are provided for future work in this field.

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The benefit of coronary stent implantation is reduced by excessive intimal hyperplasia which re-narrows the artery and the prevention of which is still a primary concern for clinicians. Abnormal hemodynamics create non-physiological viscous stress on the artery wall, one of the root causes of intimal hyperplasia following stent implantation. A methodology to comprehensively evaluate the viscous stress on the artery wall following stent implantation would be useful to evaluate a stent's hemodynamic performance.The proposed methodology employs 3D computational fluid dynamics, the variables wall shear stress (WSS), WSS gradient (WSSG), WSS angle gradient (WSSAG) and a statistical analysis to evaluate the viscous stress. The methodology is demonstrated and compared to a commonly used "threshold technique" for evaluating a stent's hemodynamic performance.It is demonstrated that the threshold technique is not adequate to fully analyse the viscous stress on the artery wall and can even be misleading. Furthermore, all three of the aforementioned variables should be considered as each provides a different perspective on the abnormalities that can arise in the arterial viscous stress.The hemodynamic performance of a stent can be assessed more comprehensively than with previously used methods by examining the arterial viscous stresses using the proposed methodology.

Abstract-Coronary stent implantation can improve blood flow in an artery that has been narrowed by the build up of arterial plaque. However, the implantation of the stent will change the geometry of the vessel wall. The haemodynamic effects of the stents presence and alteration of the vessel wall are unclear. The redistribution of flow induced vessel wall shear stress (WSS) and wall shear stress gradient (WSSG) may directly contribute to restenosis (re-blockage). Computational fluid dynamics (CFD) is used extensively to identify these parameters in stented vessels. However, simplifications to the model of the stented artery are common. In this paper, computational domains of stented arteries with increasing levels of physiological realism are created. CFD is used to predict the WSS and WSSG for each set of computational domains. Finally, the results show that certain simplifications are not valid for CFD analyses of implanted coronary stents.

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