An unsteady analysis of arterial drug transport from half-embedded drug-eluting stent

摘要

The present investigation deals with the physiological transport of drug from a half-embedded drug-eluting stent (DES), having struts of circular cross-section. The release of drug is driven by physiochemical transport forces viz. convection and diffusion where the relative strength of these two forces determines drug penetration and distribution on the arterial wall. The luminal drug distribution is modelled by the unsteady convection–diffusion equation whereas distribution within the arterial tissue is modelled by the unsteady diffusion equation only. This investigation reveals the asymmetry of drug distributions (both luminal and tissue) for different values of Peclet number. Moreover, drug deposition is highest when all strut surfaces elute drug and it is lowest when only the contacting surface is drug-eluting. The governing equations of motion accompanied by the appropriate choice of boundary and initial conditions are solved numerically by marker and cell method (MAC) in order to compute the physiologically significant quantities with desired degree of accuracy. The necessary checking for numerical stability has been incorporated in the algorithm for better precision of the results obtained. The key factors like the wall shear stress, the luminal and the tissue drug concentrations and the flow velocity profile are exhibited graphically in order to validate the applicability of the model considered herein.