Affiliation: | ∗ Department of Thoracic and Cardiovascular Surgery, Asan Medical Center, University of Ulsan College of Medicine, Seoul, South Korea;† Division of Biostatistics, Center for Medical Research and Information, University of Ulsan College of Medicine, Seoul, South Korea;‡ Department of Thoracic and Cardiovascular Surgery, Seoul Saint Mary''s Hospital, College of Medicine, Catholic University of Korea, Seoul, South Korea |