OA-Art 71.qxp

Percutaneous invasion of coronary arteries began with Andreas Gruentzig, who performed the first human percutaneous transluminal coronary angioplasty (PTCA). Stents, which overcame many of the limitations encountered with PTCA alone, were the next big milestone in the field of interventional cardiology. However, the incidence of restenosis even with stents remained high, at 20–40%. Over time, a better understanding of vascular pathology and how it responds to therapy along with advances in medical technology, led to the introduction of drug-eluting stents (DESs). Restenosis is the result of neo-intimal proliferation which occurs after the deployment of a stent. The various drugs used to coat the stent are capable of suppressing neo-intimal proliferation. Sirolimus, a macrolide antibiotic with immunosuppressive and cytostatic properties, is one such drug. It interacts with the mammalian target of rapamycin (m-TOR) receptor, causing down-regulation of cyclic dependant kinase, thereby arresting cell growth. A polymer is utilized as a vehicle to coat the surface of the stent with this drug. The polymer also controls the extended release pharmacokinetics of a drug inside the human arteries. The results of the RAVEL (RAndomized Study with the Sirolimus-eluting VELocity Balloon Expandable Stent) SIRIUS (Sirolimus-Eluting Stent in De Novo Native Coronary Lesions), RESEARCH REGISTRY, E-SIRIUS (European Sirolimus-Eluting Stent in De Novo Coronary Lesions) and many other studies have demonstrated the efficacy of and low restenosis rates following the use of sirolimus-coated stents.