Comparison of vascular response to zotarolimus-eluting stent versus sirolimus-eluting stent: Intravascular ultrasound results from ENDEAVOR III

Background The purpose of this study was to investigate the vascular response of zotarolimus-eluting stent (ZES) and sirolimus-eluting stent (SES) using serial intravascular ultrasound (IVUS). Methods Data were obtained from the Endeavor Drug-Eluting Coronary Stent System Versus the Center Siromlimus-Eluting Coronary Stent System in De Novo Native Coronary Artery Lesions (ENDEAVOR) III trial, a randomized study comparing ZES and SES for the treatment of de novo native coronary artery lesions. Serial (baseline and 8-month follow-up) IVUS was available in 258 patients (190 ZES, 68 SES). Results At 8 months, ZES had greater percentage of neointimal volume index (ZES 1.1 +/- 0.8 mm(3)/mm vs SES 0.2 +/- 0.1 mm(3)/mm, P <.01), resulting in smaller lumen volume index (6.0 +/- 2.0 mm(3)/mm vs 7.0 +/- 2.1 mm(3)/mm, P <.05). Zotarolimus-eluting stents showed larger IVUS-detectable neointimal coverage over stent surface (50.2% vs 10.5%, P <.01) and greater mean neointimal thickness (0.19 +/- 0.07 mm vs 0.10 +/- 0.06 mm, P <.01). Zotarolimus-eluting stents had a significantly lower incidence of late-acquired incomplete stent apposition. Conclusions Zotarolimus-eluting stent is associated with a significantly greater amount of neointimal hyperplasia compared with SES. This amount of hyperplasia in ZES is distributed throughout the stent at 8-month follow-up.