title: Reply.
authors.affiliation: Department of Thoracic and Cardiovascular Surgery, Seoul National University Hospital, 101 Daehak-ro, Jongno-gu, Seoul 03080, Korea.
authors.forename: Ho Young
authors.initials: HY
authors.lastname: Hwang
authors.affiliation: Department of Thoracic and Cardiovascular Surgery, Seoul National University Hospital, 101 Daehak-ro, Jongno-gu, Seoul 03080, Korea.
authors.forename: Jae-Woong
authors.initials: JW
authors.lastname: Choi
authors.affiliation: Department of Thoracic and Cardiovascular Surgery, Seoul National University Hospital, 101 Daehak-ro, Jongno-gu, Seoul 03080, Korea. Electronic address: ahnhyuk@snu.ac.kr.
authors.forename: Hyuk
authors.initials: H
authors.lastname: Ahn