1. Department of Cardiovascular Surgery, Teine Keijinkai Hospital, Sapporo, Hokkaido, Japan.
2. Department of Thoracic Surgery, Teine Keijinkai Hospital, Sapporo, Hokkaido, Japan.
3. Department of Plastic and Reconstructive Surgery, Teine Keijinkai Hospital, Sapporo, Hokkaido, Japan.