A Prospective, Randomized, 6-Month Comparison of the Coronary Vasomotor Response Associated With a Zotarolimus- Versus a Sirolimus-Eluting Stent : Differential Recovery of Coronary Endothelial Dysfunction

ObjectivesWe prospectively compared coronary endothelial dysfunction in patients with zotarolimus-eluting stent (ZES) versus sirolimus-eluting stent (SES) implantation at 6-month follow-up.BackgroundA ZES has been associated with uniform and rapid healing of the endothelium.MethodsFifty patients were randomly treated with intravascular ultrasound-guided stenting with a single stent to the mid-segment of the left anterior descending artery (20 ZES, 20 SES, and 10 bare-metal stents), and endothelial function was estimated before and after intervention at 6-month follow-up by incremental acetylcholine (Ach) (10, 20, 50, and 100 μg/min) and nitrate (200 μg/min) infusions into the left coronary ostium. The vascular response was quantitatively measured in the 5-mm segments proximal and distal to the stent.ResultsIn the drug-eluting stent groups, more intense vasoconstriction to incremental doses of Ach was observed at 6-month follow-up compared with the responses before stenting. Endothelial function associated with the ZES was more preserved at 6-month follow-up compared with the SES. Vasoconstriction to Ach was more prominent in the distal segments than the proximal segments in both the ZES and SES groups. Endothelium-independent vasodilation to nitrate did not differ significantly among the study groups.ConclusionsVasoconstriction in response to Ach in the peri-stent region was less pronounced in the ZES group than the SES group at 6-month follow-up, which suggests that endothelial function associated with ZES can be more preserved than the SES.