Impact of luminal flow on mass transport through coronary arteries : a study relevant to drug-eluting stent

Abstract

The paper is concerned with an investigation of the effects of luminal flow and drug diffusivity on drug transport from a well-apposed drug-eluting stent, having struts of trapezoidal cross-section. The problem is studied theoretically by developing a suitable numerical model. Keeping the relevance of the physiological situation in view, the model is developed where the luminal drug transport is considered as an unsteady convection diffusion process, while the drug transport within the arterial tissue is supposed to commence as an anisotropic diffusion process. Considering axi symmetry and using cylindrical coordinate system, the marker and cell (MAC) method has been used to handle the governing equations of motion for the luminal flow and the luminal and tissue drug transport in a stentbased drug delivery. Quantitative estimates of the effects of parameters like Reynolds number and Peclet number on the wall shear stress and the transport of drug through both the lumen and the tissue are obtained and the computed numerical values presented in graphical form. The study clearly indicates that with an increase in the Peclet number, there occurs a reduction in both the luminal and tissue drug concentration. Simulation of the results predicts that there exist two distinct recirculation regions from proximal and distal to
the trapezoidal strut, where the latter is significantly larger than the former. The observation is consistent with that of previous investigations available in the literature. This further validates the applicability of the present numerical model.