Mass transfer phenomena. A case study: drug-eluting stents.

A stent is a small mesh tube that is inserted permanently into a stenotic artery. The stent restores the original value of the arterial section to ensure the physiological flow rate. One of the problems caused by stent insertion is re-narrowing of the treated vessel. To overcome this phenomenon drug-eluting stents (DES) have been recently introduced. Referred to as a coated ormedicated stent, a DES is a normal metal stent that has been coated with a pharmacologic agent (drug) that is known to interfere with the process of restenosis (reblocking). However, the design of such devices is a very complex task because their performance in widening the arterial lumen and preventing further restenosis is influenced by many factors such as the geometrical design of the stent, the mechanical properties of the materials and the chemical properties of the drug that is released. Mathematical models and numerical simulation techniques are appropriate to study such phenomena with the aim to be used as a predictive tool for the effective design of drug eluting stents. We present in this section a brief review fluid dynamics and drug release models developed by the authors for the numerical simulation of drug eluting coronary stents