1. Department of Thoracic and Cardiovascular Surgery, Sejong General Hospital, Bucheon, Republic of Korea
2. Clinical Research Center, Korea University Anam Hospital, Korea University, Seoul, Republic of Korea
3. Department of Thoracic and Cardiovascular Surgery, Korea University Anam Hospital, College of Medicine, Korea University, Seoul, Republic of Korea
4. Department of Thoracic and Cardiovascular Surgery, Uijeongbu St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Uijeongbu, Republic of Korea