1. Department of Cardiovascular Surgery, JA Hiroshima General Hospital, Hiroshima, Japan
2. Department of Rehabilitation, JA Hiroshima General Hospital, Hiroshima, Japan
3. Department of Surgery, Institute of Biomedical and Health Science, Hiroshima University, Hiroshima, Japan
4. Department of Cardiovascular Surgery, Graduate School of Medicine, Hiroshima University, Hiroshima, Japan