1 Department of Cardiovascular Surgery, The Sakakibara Heart Institute of Okayama, 2-5-1, Nakai-cho, Kita-Ku, Okayama, 700-0804, Japan. kondounobuo0515@gmail.com.
2 Department of Cardiovascular Surgery, The Sakakibara Heart Institute of Okayama, 2-5-1, Nakai-cho, Kita-Ku, Okayama, 700-0804, Japan.