Background Trimetazidine (Vastinan짰) has been shown to have anti-ischemic properties. However, there is no previous data regarding its impact impact on drug-eluting stent (DES) associated coronary artery spasm (CAS). We investigated the impact of Trimetazidine on acetylcholine (Ach)-induced coronary artery spasm (CAS) and 12-month clinical outcomes in patients (pts) underwent percutaneous coronary intervention (PCI) with DES. Methods Among 1862 consecutive pts treated with DES, 1010 pts underwent repeat angiogram within 12 months either because of routine follow up or recurrent chest pain suspicious of DES associated spasm. Among them, 160 pts underwent the acetylcholine (Ach) provocation test by injecting incremental doses of 20, 50, 100 ug into the left coronary artery between March 2004 and April 2009. The Ach provocation test results, its associated parameters, and 12-month clinical outcomes of pts treated with DESs were compared between the trimetazidine group (n=66) and non- trimetazidine group (n=94). Results The baseline characteristics were similar between the two groups. All the pts who received the trimetazidine as an angina medication after the stenting, Vastinan SR짰 35mg bid daily were administered for more than 6 months. The rate of positive Ach provocation test results after the stenting and CAS associated parameters were not different between the two groups. Further, at 12 months, overall clinical outcomes including the rate of death, myocardial infarction (MI), repeat PCI, major adverse cardiac events (MACE) were similar between the two groups (Table 1). Conclusion In our study, trimetazidine administration after the DES implantation did not exert any impact on the Ach provocation test results and at least one-year major clinical outcomes.