Shear-induced platelet activation and its relationship with blood flow topology in a numerical model of stenosed carotid bifurcation

摘要

Vascular pathologies responsible for the narrowing (stenosis) of arterial lumen are a major healthcare problem in the Western world. The presence of stenosis, by further altering the yet disturbed hemodynamics within the vessel, could lead to the establishment of varying and abnormal shear stress levels which may induce activation and aggregation of platelets, thus enhancing the development of the pathology and increasing the risk for thromboembolic complications. In this study, we present a comprehensive analysis of the local hemodynamics within an image-based model of a 51% stenosed internal carotid artery, focused on the influence of the disturbed flow caused by the stenosis on transport and flow-induced activation of platelets. The flow field was resolved using computational fluid dynamics, and the flow-induced level of activation of transported platelets was predicted by adopting a consolidated Lagrangian-based blood damage model that takes into account the cumulative effect of the shear stress level and the time of exposure to it. Moreover, by adopting a Lagrangian-based bulk flow-descriptor, we investigated the influence that helical flow dynamics within the bifurcation has on platelet activation in order to assess whether a relationship exists between bulk flow structures and platelet activation levels. The results confirm that the presence of stenosis enhances the risk for flow-induced activation of platelets, and that helical flow is instrumental in moderating the burden of shear-induced activation of platelets in stenosed carotid bifurcations.