1) Department of Surgery, Nagasaki University Graduate School of Biomedical Science, Nagasaki, Japan
2) Tohoku Kosei Nenkin Hospital, Sendai, Japan
3) Department of Cardiovascular Surgery, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
4) Department of Cardiovascular Surgery, Tokyo Women's Medical University, Tokyo, Japan
5) All Japan Federation of Social Insurance Associations, Tokyo, Japan
6) Department of Cardiovascular Surgery, National Defense Medical College, Tokorozawa, Japan
7) Faculty of Economics Gakushuin University, Tokyo, Japan

Takashi Kanematsu¹⁾, Koichi Tabayashi²⁾, Ryuji Tominaga³⁾, Hiroshi Nishida⁴⁾, Masaharu Ito⁵⁾, Tadaaki Maehara⁶⁾, Hisao Endo⁷⁾