1. Department of Cardiovascular Surgery; Machida Municipal Hospital, Graduate School of Medical and Dental Science, Tokyo Medical and Dental University
2. Department of Cardiovascular Surgery; Tokyo Yamate Medical Center
3. Department of Cardiovascular Surgery; Machida Municipal Hospital
4. Department of Cardiovascular Surgery, Graduate School of Medical and Dental Science; Tokyo Medical and Dental University
5. Department of Cardiovascular Surgery; Yokosuka Kyosai Hospital
6. Department of Cardiovascular Surgery; Musashino Red Cross Hospital; Tokyo Japan