In 2005, a 64 year-old man underwent implantation of a sirolimus-eluting stent at another hospital for the treatment of severe stenosis of the right coronary artery (RCA) that caused unstable angina pectoris affecting the inferior cardiac wall. He was subsequently admitted to our hospital because of recurrent angina. Diagnostic coronary angiography, performed in November 2006, revealed 75% stenosis of the left main trunk and 99% stenosis of the left circumflex artery. We planned to perform off-pump coronary artery bypass grafting on May 6, 2007. Ticlopidine and aspirin were discontinued 14 days and 1 day before the operation, respectively. We then started continuous intravenous heparin administration. During the operation, the right internal mammary artery was grafted to the left anterior descending artery, and after rotation of the heart in order to graft to the circumflex artery, hypotension and ST elevation in electrode II occurred. The left internal mammary artery was grafted to the left circumflex artery under the support of intra-aortic balloon pumping, but the ST elevation did not normalize. Therefore, an extracorporeal cardiopulmonary bypass was started. Despite the coronary recanalization, the ST elevation in electrode II did not recover. Because of thrombosis of the drug-eluting stent, an aorto-coronary bypass graft to the RCA was performed with a saphenous vein graft. There was no proximal blood flow at the RCA incision. Therefore, we perfused the RCA via a shunt tube from the cardiopulmonary bypass, and subsequently the ST change normalized. However, ST elevation recurred after the operation. An emergency angiography performed immediately postoperatively revealed a patent saphenous vein graft and drug-eluting stent, and spastic change in the RCA distal from drug-eluting stent. After the initiation of a continuous intravenous drip of nicorandil, hypotension and the ST change recovered. Attention to coronary artery spasm after drug-eluting stent implantation is important.