Endovenous thermal ablation (EVTA), including radiofrequency ablation (RFA) and endovenous laser ablation (EVLA), is considered the main method for the treatment of symptomatic truncal vein reflux. However, there are controversial data concerning their efficacy and safety in ablating large saphenous veins because of high risk of heat-induced thrombosis (EHIT), incomplete ablation and recanalization.1-5 The use of vacuum evacuation of the remaining intraluminal blood during endovenous laser ablation allows to decrease the risk of intraoperative (carbonization and destruction of the fiber lens) and postoperative complications (EHIT, hyperpigmentation, string feeling) and leads to reduction of recovery because of short period of vein resorption. The aim of the study is to evaluate the safety and effectiveness of endovenous thermal ablation with or without vacuum evacuation for the treatment of incompetent large saphenous veins (\>15 mm).