1. Department of Cardiovascular Surgery, National Cerebral and Cardiovascular Center , Suita, Osaka, Japan
2. Department of Cerebrovascular Medicine, National Cerebral and Cardiovascular Center , Suita, Osaka, Japan
3. Department of Transfusion, Department of Anesthesiology, National Cerebral and Cardiovascular Center , Suita, Osaka, Japan
4. Department of Cardiovascular Surgery, Graduate School of Medicine, Kyoto University , Kyoto, Japan