1. Division of Emergency and Critical Care Medicine, Department of Acute Medicine, Nihon University School of Medicine, Itabashi-ku, Tokyo, Japan
2. Department of Cardiology, Nihon University Hospital, Chiyoda-ku, Tokyo, Japan
3. Department of Cardiovascular Surgery, Nihon University School of Medicine, Itabashi-ku, Tokyo, Japan
4. Department of Neurosurgery, Nihon University School of Medicine, Itabashi-ku, Tokyo, Japan.