Development of drug-eluting stents (DES)

Abstract This chapter starts with a discussion on the first coronary intervention, balloon angioplasty, and then followed by the development of stents. Stent implantation definitely reduced the incidence of acute periprocedural complications and initial failures of angioplasty (acute occlusion and elastic recoil) as well as significantly reduced the incidence of restenosis, a new narrowing that develops inside the dilated artery. However, the first-generation stents were associated with somewhat higher incidence of subacute thrombosis and late in-stent restenosis (ISR). Next, the pathophysiology of restenosis is discussed. A logical solution to the problem of restenosis was to deliver a drug at the site of the injury to stop smooth muscle cell proliferation. Thus, a typical drug-eluting stent (DES) design consists of metallic scaffolding (BMS), a layer of drug carrier substance, and antiproliferative agent itself. Subsequently, there are several ways to measure stent performance and to compare different designs: laboratory tests (mainly mechanical), animal testing, and finally, clinical trials. Finally, specific features of stent designs are discussed for first-, second- and next-generation DES.