Drug-eluting stents: Are they still the answer?
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Corresponding author Ronald J. Krone, MD Section of Cardiology, Washington University School of Medicine, 660 South Euclid, Campus Box 8086, St. Louis, MO 63110, USA. E-mail: [email protected] Current Cardiovascular Risk Reports 2008, 2:334 –341 Current Medicine Group LLC ISSN 1932-9520 Copyright © 2008 by Current Medicine Group LLC
Drug-eluting stents have profoundly impacted the interventional cardiology field. Their efficacy against the smooth muscle hyperplasia responsible for in-stent restenosis has significantly altered practice patterns and patient selection for percutaneous and surgical revascularization. However, their potent antiproliferative properties and polymer coatings delay the healing process of the arterial wall and appear to prolong the duration of stent thrombogenicity. The actual clinical impact of this effect is controversial. However, the sequelae of stent thrombosis can be catastrophic and have driven much recent discussion on this subject. This article attempts to provide perspective on the benefits and limitations of these devices so that their use achieves maximum benefit and lowest risk.
Introduction The fi rst coronary stent was placed by Sigwart and Puel in 1986 to treat acute vessel closure secondary to percutaneous transluminal coronary angioplasty (PTCA). It soon became apparent that mechanical scaffolding ameliorated acute and chronic recoil, resulting in better luminal gains and lower restenosis rates than PTCA alone [1]. However, early coronary stent use was complicated by high subacute (1–30 days after deployment) thrombosis rates despite aggressive anticoagulation regimens. It was not until the benefits of routine high pressure stent deployment [2] and dual antiplatelet therapy [3] were appreciated that coronary stent placement achieved contemporary thrombosis rates of less than 1%, permitting routine use. Although superior to PTCA alone, routine coronary stenting continued to have high 6-month target lesion revascularization rates. Vessel injury caused by stent
deployment was found to induce arterial wall smooth muscle cell proliferation and migration within the stent. To combat this in-stent restenosis, drug-eluting stents (DES; stents coated with polymer-eluting antiproliferative drugs) were developed. In 2002, the fi rst randomized trial between a bare metal stent (BMS) and a stent eluting the cell cycle inhibitor sirolimus (SES) was released [4]. The SES treatment group demonstrated no angiographic target lesion restenosis at 6 months compared with a 26% restenosis rate in the BMS arm. In addition, a marked improvement existed in event-free survival and target lesion revascularization rates at 1 year. In 2004, TAXUSIV, a randomized controlled trial comparing a stent eluting the antimicrotubule agent paclitaxel with BMS, showed similar promising results [5]. Because of their effectiveness at reducing target lesion revascularization, DES use rapidly penetrated the US market and expanded to lesion subtypes not included in the original studies. Concerns about the thrombotic ri
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