A 76-year-old man received implantation of sirolimus-eluting stent for total occlusion of the left circumflex artery causing an acute myocardial infarction of posterolateral wall on May 21st, 2005. Off-pump coronary artery bypass grafting was performed on June 9th for a residual 90% stenosis on the proximal segment of his left anterior descending artery. Ticlopidine and aspirin were discontinued 7 days and 2 days before the operation, respectively. Continuous intravenous drip of heparin had been given for 5 days until just prior to the operation. Though the left internal thoracic artery was successfully grafted onto the left anterior descending artery, he developed an acute myocardial infarction after the operation. An emergency angiography, performed on the 1st postoperative day showed thrombotic occlusion of the sirolimus-eluting stent in the circumflex artery and patent internal thoracic artery to the left anterior descending artery. Percutaneous catheter intervention restored the stent patency. Antiplatelet therapy including ticlopidine or clopidogrel is mandatory to prevent subacute thrombosis in drug-eluting stent. Hemorrhagic complication or major surgery may hinder continuing antiplatelet regimens and trigger acute thrombosis. Alternative antiplatelet and/or anticoagulant therapy is essential to prevent acute stent occlusion in such clinical settings.