Flow-Mediated Drug Transport from Drug-Eluting Stents is Negligible: Numerical and In-vitro Investigations.

Abstract

Prior numerical studies have shown that the blood flow patterns surrounding drug-eluting stents can enhance drug uptake in stented arteries. However, these studies employed steady-state simulations, wherein flow and drug transport parameters remained constant with respect to time. In the present study, numerical simulations and in-vitro experiments were performed to determine whether luminal blood flow patterns can truly enhance drug uptake in stented arteries. Unlike the aforementioned studies, the time-varying depletion of drug within the stent coating was modelled and the simulation results were validated qualitatively with the in-vitro experiments. The simulations showed that the non-Newtonian properties of blood, its complex near-wall behavior, and the pulsatility of its flow all affect drug uptake only modestly. Furthermore, flow-mediated drug transport was found to be negligible due to the rapid rate at which drug depletes at the stent coating surfaces that are exposed to arterial blood flow. For fluid dynamicists, these results show that steady-state simulations must be avoided when modelling drug transport in stented arteries. For device designers, these results may be used to optimize the shape of drug-eluting stent struts and coatings to improve stent efficacy.