A 63-year-old man was admitted to our hospital for acute myocardial infarction. A cardiac catheter study showed 3 vessels coronary disease. He was treated by percutaneous coronary intervention for a left anterior descending arterial (LAD) lesion. Unfortunately, cardiac tamponade following stenting for LAD was complicated. A percutaneous cardiopulmonary support system was commenced along with an emergent coronary artery bypass grafting to the LAD and obtuse marginal branch. A quadricuspid aortic valve was discovered by an aortotomy and identified as Hurwitz-Roberts classification type b. Blood from the left coronary main trunk had already stopped. Intraaortic balloon pumping was instituted while weaning from the cardiopulmonary bypass. The patient's postoperative course was uneventful and all bypass grafts were sufficient. He was well 1 year after the operation.