Mass transfer by advection and diffusion from a drug-eluting stent

Stents are often used to maintain the diameter of the coronary artery lumen. The insertion of a stent into an artery often results in the accumulation of scar tissue in response to the stent’s presence. Drug-eluting stents dispense a drug designed to limit the growth of such scar tissue, thus reducing the likelihood of restenosis. The trajectory of the eluted drug is of critical clinical importance. The bifurcation of the drug between the artery tissue and the blood-carrying lumen is a highly relevant issue to the success of stenting. Prior simulations of this issue have dealt with highly specific situations. Here, the problem is nondimensionalized in order to obtain universal solutions. The results, in terms of the Sherwood number, are reported in terms of the Reynolds and Schmidt numbers, and a mass-transfer version of the Biot number. It was found that the highest rates of mass transfer occurred at the forwardmost portion of the stent. The rate of drug delivery to the lumen was greater than that to the artery tissue.