A 27-year-old female with Marfan's syndrome underwent successful emergency surgery for rupture of an abdominal aortic aneurysm. Annulo-aortic ectasia with a saccular aneurysm of the aortic arch was revealed by angiography after the initial operation. Cabrol's operation with replacement of the aortic arch was performed. Because bleeding from the distal anastomotic portion was uncontrollable, the segment was ligated and an extra-anatomical bypass was performed from the ascending aortic graft to the bilateral femoral arteries. Intra-graft balloon pumping was carried out in the extra-anatomical bypass graft while the patient was in low cardiac output condition after the second operation. This was considered to be an effective circulatory assist procedure.