Stents are implanted to dilate arteries narrowed by atherosclerotic plaques and to revascularize coronary arteries following myocardial infarction. However, in up to 20% of patients the regrowth of cells in the inner vessel wall or incomplete healing of the endothelial cell lining in the vessel lumen can cause recurrent arterial obstruction known as restenosis.
Over the last decade, stent technology has been introduced and shown excellent performance in prevention of occlusion and restenosis when compared with conventional angioplasty. With the introduction and development of drug-eluting chemistries, stents have revolutionized the treatment of coronary artery disease, by significantly reducing stent restenosis and the need for target vessel revascularization. However, with the dramatic increase in the use of these drug eluding chemistries, stent thrombosis has become a major concern. Since restenosis and thrombosis are caused by multiple factors, an ideal stent coating including drug-vehicle materials and pharmaceutical agents should not only inhibit thrombus formation, inflammatory reaction, and proliferation of smooth muscle cells, but also facilitate the process of re-endothelialization.