Features and Parameters of Drug-Eluting Stent Deployment Discoverable by Intravascular Ultrasound

Abstract

The only routinely available tool for assessing many features of stent implantation, intravascular ultrasound (IVUS) has become indispensable in trials of drug-eluting stents (DESs) and is currently the best way to identify or exclude causes of DES failure. Although IVUS resolution is not sufficient for determining reendothelialization, serial (postprocedure and follow-up) IVUS can measure intimal hyperplasia (IH), assess acute and late incomplete stent apposition, detect the presence and persistence of edge dissections, assess vascular responses such as remodeling, study edge effects, compare overlapping with nonoverlapping segments, and look for causes of restenosis and thrombosis. Percentage IH volume is one IVUS measure of efficacy that has been routinely assessed and compared in studies of DESs; IH volume and external elastic membrane, luminal, and stent cross-sectional area are others. This review details and evaluates IVUS findings in the important clinical trials conducted with the first-generation DESs: a sirolimus-eluting stent, a polymeric paclitaxel-eluting stent, and a nonpolymeric paclitaxel-eluting stent. IVUS results apparent in DES failure (restenosis and thrombosis) are also examined.