Contemporary Reviews in Interventional Cardiology Edge Effect From Drug-Eluting Stents as Assessed With Serial Intravascular Ultrasound A Systematic Review

Several studies have demonstrated effective reduction of intimal hyperplasia within a drug-eluting stent (DES) when compared with a bare metal stent (BMS), thereby resulting in a lower incidence of target lesion revascularization.1–3 Restenosis at the stent edges, however, is not appreciably reduced by DES. Thus, to understand stent edge effect in DES, it is important to improve the efficacy of this technology. The concern that stent edge effects alter intimal hyperplasia in the stent but not at the edges has existed for many years, and often is described as the “candy wrapper phenomenon.” This phenomenon was first described in radioactive stents4,5 and is due to local inhibition of intimal growth and endothelial healing6 only within the stent. Many DES trials, therefore, sought to better understand the edge effect using intravascular ultrasound (IVUS) to assess the vessel response post stent implantation. Many studies have documented DES edge effect in olderand newer-generation DES. One challenge facing IVUS studies that assess DES edge effect is a high degree of patient-to-patient variability, along with potential variability among the different DES types. Because of these variables and the relatively small size of most sequential IVUS studies, there is no general consensus regarding stent edge effect in DES. We therefore reviewed the literature to find common findings and tendency. This review focused on 4 DES types approved by the United States Food and Drug Administration: the Cypher sirolimus-eluting stent (SES) (Cordis), the Taxus paclitaxel-eluting stent (PES) (Boston Scientific), the Endeavor zotarolimus-eluting stent (ZES) (Medtronic CardioVascular Inc.), and the XIENCE V everolimus-eluting stent (EES) (Abbott Vascular).