1 Department of Thoracic and Cardiovascular Surgery, Nara Medical University, 840 Shijo-cho, Kashihara, Nara, 634-8521, Japan. Electronic address: nsawabata@hotmail.com.
2 Department of Thoracic and Cardiovascular Surgery, Nara Medical University, 840 Shijo-cho, Kashihara, Nara, 634-8521, Japan.