Coated stents: local pharmacology.

Despite excellent restoration of acute vessel perfusion, coronary stenting has been limited by subacute thrombosis within 3-10 days and by neointimal proliferation leading to restenosis by 6 months post-intervention. A variety of pharmacotherapeutics have been utilized in an attempt to prevent these sequelae. Drug regimens that reduce thrombosis have the potential for serious toxicities, and no regimen to date has been shown clinically to reduce the incidence of restenosis. Local drug delivery via stents coated with immobilized drug or coated with a drug-releasing polymer matrix offers the possibility of focal therapeutic drug effect within target tissues without serious side-effects arising from systemic drug administration. Before the promise of this treatment modality is realized, however, a more detailed understanding is needed of the local pharmacologic influences on drug activity. Drug-device parameters, such as stent surface area and mode of drug attachment, and drug-tissue parameters, including drug solubility in and non-specific binding to tissues, interact in a complex manner to determine local tissue drug dose, distribution and, consequently, effect.