Dual antiplatelet therapy (DAPT) after percutaneous coronary intervention increases the risk of bleeding. We studied the safety and clinical outcomes of switching from DAPT to aspirin monotherapy at 3 months after ZES implantation. We retrospectively evaluated 168 consecutive patients with coronary artery disease who had been implanted with a ZES from June 2009 through March 2010. After excluding 40 patients according to exclusion criteria such as myocardial infarction, 128 patients were divided into a 3-month DAPT group (67 patients, 88 lesions) and a 12-month conventional DAPT group (61 patients, 81 lesions). Coronary angiographic followup and clinical followup were conducted at more than 8 months and at 12 months after ZES implantation, respectively. Minor and major bleeding events, stent thrombosis (ST), and major adverse cardiac events (MACE) (death, myocardial infarction, cerebrovascular accident, target lesion revascularization, and target vessel revascularization) were evaluated. There were no statistically significant differences in the incidences of ST and MACE between the two groups. The incidence of bleeding events was significantly lower in the 3-month group than in the 12-month group (1.5% versus 11.5%, ). DAPT can be safely discontinued at 3 months after ZES implantation, which reduces bleeding risk. 1. Introduction DESs have reduced the incidences of in-stent restenosis and target lesion revascularization (TLR) compared to those with bare-metal stents (BMS). The 2007 Focused Update of ACC/AHA/SCAI Guidelines for Percutaneous Coronary Intervention (PCI) recommends dual antiplatelet therapy (DAPT) with aspirin and a thienopyridine drug ideally up to 12 months after DES implantation [1]. This long DAPT after DES implantation is associated with an increased risk of bleeding, for example, gastrointestinal bleeding and intracranial hemorrhage [2–11]. Major bleeding may deteriorate the quality of life of patients by deferring an endoscopic, dental, or surgical procedure [12]. Little evidence about the optimal duration of DAPT is available [4, 7]. Recent studies demonstrated that the duration of DAPT might be shortening when an endeavor zotarolimus-eluting stent (ZES, Medtronic Inc., Santa Rosa, CA) is used. ZES is a second-generation cobalt-alloy DES that has a highly biocompatible polymer permitting rapid release of the antiproliferative substance zotarolimus. ZES has been reported (1) to accelerate arterial healing compared with other DESs in animals [13–15], (2) to be safe in humans for 5 years [16], and (3) to have a low risk for
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