[1] Osaka Univ Hosp, Dept Cardiovasc Surg, Yamadaoka 2-2, Suita, Osaka 5650871, Japan
[2] Dokkyo Koshigaya Med Ctr, Dept Cardiovasc Surg, Saitama, Japan
[3] Chiba Univ Hosp, Dept Cardiovasc Surg, Chiba, Japan
[4] Hyogo Coll Med, Dept Cardiovasc Surg, Nishinomiya, Hyogo, Japan
[5] Dokkyo Univ, Med Sch Hosp, Dept Cardiovasc Surg, Mibu, Tochigi, Japan
[6] Osaka Police Hosp, Dept Cardiovasc Surg, Osaka, Japan
[7] Ehime Univ Hosp, Dept Cardiovasc Surg, Matsuyama, Ehime, Japan
[8] Rinku Gen Med Ctr, Dept Cardiovasc Surg, Osaka, Japan