1. Department of Thoracic and Cardiovascular Surgery, Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul 06273, Republic of Korea
2. Department of Thoracic and Cardiovascular Surgery, National Health Insurance Service Ilsan Hospital, Goyang 10444, Republic of Korea
3. Department of Thoracic and Cardiovascular Surgery, Kangbuk Samsung Hospital, Sungkyunkwan University College of Medicine, Seoul 03181, Republic of Korea