1. Division of Vascular and Transplant Surgery, Department of Surgery, College of Medicine, The Catholic University of Korea, Seoul, Korea.
2. Divison of Vascular Surgery, Department of Surgery, Seoul National University Bundang Hospital, Seongnam, Korea.
3. Department of Biostatistics, School of Medicine, Inha University, Incheon, Korea.
4. Department of Biostatistics, Graduate School of Korea University, Seoul, Korea.