Jae Gun Kwak1, Chang-Ha Lee2, Seong Ho Kim3. 1. Department of Thoracic and Cardiovascular Surgery, Sejong General Hospital, Bucheon, Gyeonggi, Republic of Korea. 2. Department of Thoracic and Cardiovascular Surgery, Sejong General Hospital, Bucheon, Gyeonggi, Republic of Korea. Electronic address: leechha@gmail.com. 3. Department of Pediatrics, Sejong General Hospital, Bucheon, Gyeonggi, Republic of Korea.