Intravascular Ultrasound Findings in ENDEAVOR II and ENDEAVOR III

The results of 2 randomized controlled trials of the Endeavor zotarolimus-eluting stent (ZES; Medtronic Vascular, Santa Rosa, CA) were recently reported: ENDEAVOR II, in which the Endeavor stent was compared with the Driver bare metal stent (BMS; Medtronic Vascular), and ENDEAVOR III, in which the Endeavor stent was compared with the first-generation Cypher sirolimus-eluting stent (SES; Cordis Corporation, Miami Lakes, FL). To examine in detail the vascular responses to the Endeavor stent, serial intravascular ultrasound (IVUS) analyses were performed in subsets of patients in the 2 trials at baseline and 8-month follow-up. The investigators report results for various IVUS parameters and compare those with published results for the first-generation SES and paclitaxel-eluting stent (PES). The ZES demonstrated significantly improved effectiveness and equivalent safety compared with the BMS in ENDEAVOR II. Although the ZES seems to be slightly less effective at inhibiting intimal hyperplasia than the SES and PES, early results are indicative of an acceptable safety profile. This finding may be due in part to the relatively complete and uniform neointimal coverage associated with the ZES.