1. The Japanese Association for Thoracic Surgery Tokyo Japan
2. Department of Cardiac Surgery The University of Tokyo Hospital Tokyo Japan
3. Department of Cardiovascular Surgery Keio University Hospital Tokyo Japan
4. Department of Healthcare Quality Assessment University of Tokyo Japan
5. The Japan Cardiovascular Surgery Database Organization Tokyo Japan
6. Department of Cardiovascular Surgery Toho University Sakura Medical Center Sakura Japan
7. Takatsuki General Hospital Cardio‐Aortic Center Osaka Japan