Stent thrombosis (ST) is a rare but devastating adverse event after percutaneous coronary intervention(PCI), which results in abrupt closure of the treated artery with the risk of sudden death or myocardial infarction (MI).1 Very late (beyond 1 year) ST is even rarer and more common with drug-eluting stents(DES) compared to bare-metal stents (BMS) , representing a distinct entity complicating the use of DES.2, 3Case Report A 39 years old male who received primary PCI due to acute coronary syndrome (ACS) on Sep 18th,2008.A 3.5 mm × 28 mm sirolimus-eluting stent was implanted at proximal left anterior descending coronary artery (LAD) (Figure 1A, B).The patient received dual antiplatelet therapy (aspirin l00mg qn, clopidogrel 75 mg qd) , atorvastatin 20mg and metoprolol 12.5mg bid after procedure and remained symptomless.Since follow-up coronary angiography (CAG) on Jun 16th, 2009 showed slight haziness along proximal and middle part of stent in LAD (Figure 2), the patient kept receiving prior dual antiplatelet therapy.