Yuki Ikeno1, Katsuhiro Yamanaka1, Hiroshi Tanaka1, Yutaka Okita2. 1. Department of Cardiovascular Surgery, Kobe University Graduate School of Medicine, Kobe, Japan. 2. Department of Cardiovascular Surgery, Kobe University Graduate School of Medicine, Kobe, Japan. Electronic address: yutakaokita@gmail.com.