1Department of Cardiovascular Surgery, Keio University, 35, Shinanomachi, Shinjuku-ku, Tokyo, Japan
2Department of Surgical Oncology, Hiroshima University, Hiroshima, Japan
3Department of Gastroenterological Surgery, National Hospital Organization Kyushu Cancer Center, Fukuoka, Japan
4Department of Gastroenterological Surgery, Osaka University, Suita, Osaka, Japan
5Department of Thoracic Surgery, Jichi Medical University, Shimotsuke, Japan
6Department of Cardiac and Vascular Surgery, Dokkyo Medical University School of Medicine, Shimotsuga-gun, Tochigi, Japan
7Department of Cardiac Surgery, The University of Tokyo Hospital, Tokyo, Japan
8Department of General Thoracic Surgery, Gifu University Hospital, Gifu, Japan
9Department of Cardiovascular Surgery, National Cerebral and Cardiovascular Center, Suita, Japan
10Department of Healthcare Quality Assessment, Graduate School of Medicine, University of Tokyo, Tokyo, Japan
11Department of Health Policy and Management, Keio University, Tokyo, Japan
12Department of Cardiovascular Surgery, Toho University, Sakura Medical Center, Sakura, Japan
13Department of Digestive Surgery, Breast and Thyroid Surgery, Kagoshima University Graduate School of Medicine, Kagoshima, Japan
14Department of Gastroenterological Surgery, Tokai University School of Medicine, Isehara, Japan
15Division of Cardiovascular Surgery, Tohoku University Graduate School of Medicine, Sendai, Japan
16Department of Chest Surgery, St. Marianna University School of Medicine, Kawasaki, Japan
17Department of Thoracic Surgery, University of Tsukuba, Tsukuba, Japan
18Department of Cardiovascular Surgery, Mitsui Memorial Hospital, Tokyo, Japan
19Department of Cardiovascular Surgery, Kawasaki Medical School, Kurashiki, Japan
20Department of Thoracic, Endocrine Surgery and Oncology, Institute of BioMedicine, Tokushima University Graduate School, Tokushima, Japan
21Division of Cardiovascular Surgery, Department of General Surgical Science, Gunma University, Maebashi, Japan
22Department of Gastroenterological Surgery, Cancer Institute Hospital of Japanese Foundation for Cancer Research, Tokyo, Japan
23Department of Cardiovascular Surgery, Graduate School of Medicine, Kyoto University, Kyoto, Japan
24Chunichi Hospital, Nagoya, Japan
25Cardio-aortic Center, Takatsuki General Hospital, Takatsuki, Japan
26Division of Thoracic and Cardiovascular Surgery, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
27Department of Cardiovascular Surgery, Graduate School of Medicine, Osaka University, Osaka, Japan