1. Division of Cardiology, Nowon Eulji Medical Center, Eulji University School of Medicine, Seoul, Korea.
2. Division of Vascular Surgery, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
3. Cardiovascular Center, Korea University Guro Hospital, Seoul, Korea.
4. Division of Cardiology, Department of Internal Medicine, Kangwon National University School of Medicine, Chuncheon, Korea.