During September 13th – 14th, 2022, Assoc. Prof. Nuttawut Sermsathanasawadi of the Division of Vascular Surgery, Department of Surgery, Faculty of Medicine Siriraj Hospital, Mahidol University, attended the “XIX World Congress of the International Union of Phlebology” in Istanbul, Turkey, and delivered two special lectures on the topics: “Treatment of marginal vein in KT: Endovenous thermal ablation or foam?” and “Vein ablation by glue – Safety and efficacy issues.” including moderated the of the UIP session 10: Vein and Lymphatic University – UIP: What would I do? and Non-Thermal Non-Tumescent Ablation Strategies and Techniques.