1. Department of Cardiovascular Surgery, Fukushima Medical University, School of Medicine
2. Department of Plastic and Reconstructive Surgery, Tokyo Women’s Medical University
3. Iwata Vascular and Vein Clinic
4. Sakata Vascular Surgery Clinic
5. Department of Surgery, Metropolitan Health and Medical Treatment Corporation Ohkubo Hospital
6. Department of Cardiovascular Surgery, Tokyo Medical University
7. Department of Cardiovascular Surgery, Yokohama Minami Kyosai Hospital
8. Department of Cardiology, Mie University Graduate School of Medicine
9. Tsukuba Vascular Center, The Committee for Survey of the Japanese Society of Phlebology