1. Department of Thoracic and Cardiovascular Surgery, Dongguk University Ilsan Hospital, Dongguk University School of Medicine, Goyang, Korea.
2. Division of Cardiac Surgery, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA.
3. Department of Thoracic and Cardiovascular Surgery, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.