1. Department of Cardiovascular Surgery, Fukuoka Tokushukai Hospital, Kasuga, Fukuoka, Japan
2. Department of Cardiovascular Surgery, Ureshino Medical Center, Ureshino, Saga, Japan
3. Department of Cardiovascular Surgery, Oosumikanoya Hospital, Kanoya, Kagoshima, Japan
4. Department of Thoracic and Cardiovascular Surgery, Saga University School of Medicine, Saga, Saga, Japan