A 66-year-old man with thoracic and abdominal aortic aneurysm suffered from microembolism in the lower extremities after total arch replacement. He presented with livedo reticularis with palpable peripheral pulses, and the serum creatinine kinase level elevated up to 7,695. The abdominal aortic aneurysm, but not the thoracic aorta, was the origin of this complication. The morphological change of thrombus in the abdominal aorta detected by ultrasonography was the key to the diagnosis. Graft replacement of the abdominal aorta finally resolved his problem.