[1] New Tokyo Hosp, Dept Cardiovasc Surg, 1271 Wanagaya, Matsudo, Chiba 2702232, Japan
[2] Midori Hosp, Dept Cardiovasc Surg, 1-16 Edayoshi,Nishi Ku, Kobe, Hyogo 6512133, Japan
[3] Takatsuki Gen Hosp, Dept Cardiovasc Surg, Takatsuki, 1-3-13 Kosobe Machi, Takatsuki, Osaka 5691192, Japan
[4] Kyoto Prefectural Univ Med, Dept Cardiovasc Surg, Kamigyo Ku, Kyoto 6028566, Japan
[5] Natl Cerebral & Cardiovasc Ctr, Dept Cardiovasc Surg, 6-1 Kishibe-Shimmachi, Suita, Osaka 5648565, Japan
[6] Saiseikai Kumamoto Hosp, Dept Cardiovasc Surg, 5-3-1 Chikami,Minami Ku, Kumamoto, Kumamoto 8614101, Japan
[7] Kawasaki Saiwai Hosp, Dept Cardiovasc Surg, 31-27 Omiya Chyou,Saiwai Ku, Kawasaki, Kanagawa 2120014, Japan
[8] Nagoya Daiichi Hosp, Japanese Red Cross Aichi Med Ctr, Dept Cardiovasc Surg, 3-35 Michishita Chyou,Nakamura Ku, Nagoya, Aichi 4530046, Japan
[9] Kansai Med Univ, Dept Cardiovasc Surg, 2-5-1 Shin Machi, Hirakata, Osaka 5731010, Japan
[10] Hyogo Coll Med, Dept Cardiovasc Surg, 1-3-6 Minatojima,Chuo Ku, Kobe, Hyogo 6500045, Japan
[11] Yokohama City Univ, Sch Med, Dept Biostat, 3-9 Fukuura,Kanazawa Ku, Yokohama, Kanagawa 2360004, Japan
[12] Tottori Univ, Dept Cardiovasc Surg, 4-101 Koyama Cho, Minami, Tottori 6808550, Japan
[13] Osaka Univ, Grad Sch Med, Dept Cardiovasc Surg, 2-2 Yamadaoka, Suita, Osaka 5650871, Japan