1. Ochanomizu Vascular and Vein Clinic, Tokyo, Japan
2. Cardiovascular Center, Fukushima Daiichi Hospital, Koriyama, Fukushima, Japan
3. Department of Surgery, Sendai Hospital of East Japan Railway Company, Sendai, Miyagi, Japan
4. Shokoku Shintaro Clinic, Okayama, Okayama, Japan
5. Tsukuba Vascular Center, Moriyakeiyu Hospital, Moriya, Ibaraki, Japan