1. Department of Cardiovascular Surgery, Hachioji Medical Center, Tokyo Medical University, Tokyo, Japan,
2. Sakakibara Heart Institute, Tokyo, Japan,
3. School of Medicine, Keio University, Tokyo, Japan,
4. School of Medicine, Jikei University, Tokyo, Japan,
5. Tokyo Women's Medical College, Tokyo, Japan,
6. Kanto Teishin Hospital, Tokyo, Japan,
7. School of Medicine, Junntendo University, Tokyo, Japan,
8. Mitsui Memorial Hospital, Tokyo, Japan