Platelet activation in flow through a stenosis model: Comparison between CFD and CDPIV results

The activation of the hemostatic system is related to platelet activation, and may be initiated by a series of rheological and hemodynamic processes. The cumulative effect of the shear stress level and the duration the platelet is exposed to, can determine whether it is brought beyond its activation threshold. Thus, time histories of individual platelets tracked down to locate the regions where activated platelets might be found. For this purpose Numerical simulations (NS) of 3D eccentric and axisymmetric models of a coronary stenosis was conducted. NS were validated by Continuous Digital Particle Image Velocimetry (CDPIV). The results indicated that platelets that were exposed to elevated stresses at the stenosis throat and then entrapped in the recirculation zone had a higher incidence of activation. The decrease in wall shear stress in the recirculation zone diminished the capacity of the geometry to embolize the deposits, allowed, at the same time for prolonged contact with the wall, and led to possible thrombus formation.