Understanding the Drug-Eluting Stent Trials

The advent of intravascular stenting dramatically reduced the incidence of restenosis among patients undergoing percutaneous transluminal coronary angioplasty. However, a substantial percentage of patients, particularly those with risk factors such as diabetes mellitus or complicated lesions, remain at risk for restenosis. Drug-eluting stents overcome this problem by releasing bioactive agents from a polymeric coating directly into the vessel wall, inhibiting the cellular mechanisms of restenosis while avoiding systemic toxicity. Recent data indicate that local targeting of the proliferative process with drug-eluting stents dramatically reduces the risk for restenosis, even among high-risk patients. A range of bioactive coatings are currently available or in late clinical trials. Both sirolimus- and paclitaxel-eluting stents have demonstrated efficacy in a broad range of patient types; early data from clinical trials of second-generation stent coatings, such as everolimus and ABT-578 (zotarolimus), suggest that these agents are also effective in preventing restenosis. This article reviews the pathophysiology of in-stent restenosis and surveys recent key clinical trials of drug-eluting stents.