The case was a 65-year-old woman. She underwent graft replacement of ascending aorta because she developed Stanford type A acute aortic dissection in November 2016. After six months she had a fever, so she underwent contrast-enhanced computed tomography and echocardiography at the previous hospital. An abnormal shadow was found in the artificial blood vessel, and the blood culture test was positive. The abnormal shadow was suspected to be a vegetation and was referred to our department. Vegetation was highly mobile and emergency surgery was performed considering the risk of embolism. Intraoperative findings showed that vegetation was attached to the anastomotic site of the artificial blood vessel. She was transferred to a rehabilitation hospital 57 days after the operation and is currently rehabilitating.