1. Division of Vascular Surgery, Department of Surgery, Tohoku University Graduate School of Medicine, Sendai, Miyagi, Japan
2. Division of Vascular Surgery, Department of Surgery, Ishinomaki Red Cross Hospital, Ishinomaki, Miyagi, Japan
3. Division of Vascular Surgery, Department of Surgery, Japan Community Health Care Organization Sendai Hospital, Sendai, Miyagi, Japan
4. Division of Vascular Surgery, Department of Surgery, Iwate Prefectural Isawa Hospital, Osyu, Iwate, Japan