A 75-year-old female was admitted to our hospital with sudden back pain and right leg ischemia. Computed tomography showed acute type A aortic dissection with the occlusion of the right common iliac artery. The patient was treated with ascending aorta replacement and femoro-femoral bypass. Three hours after the operation, the patient went into a sudden shock. Electrocardiogram showed ventricular tachycardia and ventricular fibrillation. Percutaneous cardio-pulmonary support was administered and coronary arteriogram (CAG) was proceeded for evaluation of the coronary arteries. Although CAG revealed normal coronary arteries, intravascular ultrasound showed mobile intimal flap at left main coronary artery trunk, suggesting dissection of the coronary artery. Percutaneous coronary intervention of the left main coronary artery trunk was performed. The patient recovered from shock and was discharged from the hospital without any major complication.