With a recent approval of new DES, zotarolimus-eluting stent (Endeavor, Medtronic, Minneapolis, MN), other comparison studies have been conducted to compare Endeavor zotarolimus-eluting stent with the sirolimus-eluting stent and paclitaxel-eluting stent. zotarolimus and sirolimus share some common structural and biological properties. In vitro data suggest that sirolimus and tetrazole containing rapamycin analogs have similar inhibitory effects in a mixed lymphocyte reaction assay. The ENDEAVOR clinical trials are currently in progress to evaluate a phosphoryl choline (PC)-coated zotarolimus-eluting stent(ZES) for the prevention of restenosis. The Endeavor zotarolimus-eluting stent utilizes a cobalt alloy balloon-expandable stent (Driver; Medtronic) with a geometry similar to the stainless steel stent used in this preliminary study (S7; Medtronic). The Endeavor ZES also employees a PC strut surface coating as the drug delivery reservoir with a dose of 10 g/mm of ABT-578. The Endeavor (ZES), however, differs from the stent used in this experimental study by the addition of a drug-free PC topcoat to serve as a diffusion barrier to retard drug release from the polymer reservoir. Angiographic analysis at 4 months in the 100-patient focal de novo lesion ENDEAVOR I feasibility study demonstrated a mean in-stent percent diameter stenosis of approximately 14% and a late lumen loss of 0.3 mm with a low frequency of target lesion revascularization (1%). The clinical outcomes from the ENDEAVOR II (1,500 patients randomized to ABT-578 or bare metal stent) and the ENDEAVOR III (436 patients randomized 3:1 to ABT-578 or Cypher) trials as well as other ongoing studies showed efficacy of the PC-coated ABT-578-eluting stent. In ENDEAVOR III study, the Endeavor stent had larger late loss and higher binary restenosis in both the analysis segment and stented segment.