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, Samsung Medical Center, Sungkyunkwan University College of Medicine, Seoul 06351, Republic of Korea
3. Department of Emergency Medicine, Hanyang University Seoul Hospital, Hanyang University College of Medicine, Seoul 04763, Republic of Korea
4. Department of Medicine, College of Medicine, Hanyang University, Seoul 04763, Republic of Korea
5. Biostatistics Lab, Medical Research Collaborating Center, Hanyang University, Seoul 04763, Republic of Korea
6. Department of Thoracic and Cardiovascular Surgery, Hanyang University Seoul Hospital, Hanyang University College of Medicine, Seoul 04763, Republic of Korea
7. Department of Thoracic and Cardiovascular Surgery, Korea University Anam Hospital, Korea University College of Medicine, Seoul 02841, Republic of Korea
8. Division of Cardiac Surgery, Department of Surgery, Johns Hopkins Hospital, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
9. Division of Neurosciences Critical Care, Department of Neurology, Neurosurgery, Anesthesiology and Critical Care Medicine, Johns Hopkins Hospital, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA