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).

Preoperatively all patients should be examined in a standing position clinically and with duplex ultrasound (DUS) marking of the diameters of the target great saphenous veins (GSV) or small saphenous veins (SSV) at the following levels:

• great saphenous vein: saphenofemoral junction (SFJ), vein ectasia below the SFJ by 3 cm, upper third of the thigh, middle third of the thigh, lower third of the thigh, upper third of the leg, middle third of the leg, lower third of the leg;
• small saphenous vein: saphenopopliteal junction (SPJ), ectasia below the SPJ by 3 cm, upper third of the leg, middle third of the leg, lower third of the leg.

It is recommended to calculate the required linear energy density (LEED) per centimeter of vein length using the following formula depending on the level of measurement of the target vein diameter: LEED=d*k, where LEED is the linear energy density (J/cm), "d" is the vein diameter (mm), "k" is the coefficient based on the measurement level: upper half of the thigh - 10, lower half of the thigh - 8, upper half of the leg - 6, lower half of the leg - 4.

Under local anesthesia, the target vein is punctured and the introducer is then installed. For the first group of patients (ELVeS Radial 2ring fiber), there is no need for preliminary preparation of the fiber. For the second group (ELVeS Radial 2ring Pro fiber), it is recommended to fill the ELVes Radial 2ring Pro catheter with a pre-prepared heparin solution (200 ml 0.9% Na Cl + 1 ml (5000) heparin) before use. Passing the fiber and installing it in the orifice of the target vein. Performing tumescent anesthesia (1000 ml 0.9% NaCl, 10 ml 2% lidocaine, 0.25 ml 0.1% adrenaline, 56 ml 4% sodium bicarbonate at room temperature) with recording the volume of the solution used. Performing EVLA with recording the parameters at different levels (power, extraction rate). When performing laser obliteration in patients of the second group, the ELVeS Radial 2ring Pro fiber catheter is connected to a vacuum suction using a high-pressure line to evacuate residual blood from the lumen of the vein during EVLA. Compression underwear of class 2 according to RAL or class 3 according to ASQUAL (23-32 mm Hg).

Inclusion Criteria:

• Age over 18 years
• Varicose veins of the lower extremities with clinical class C2-C6 with a diameter of the GSV or SSV ≥ 15 mm in a standing position
• Informed consent

Exclusion Criteria:

• pregnancy or lactation
• malignant neoplasms
• inability or unwillingness of any patient to wear compression stockings
• hypersensitivity to lidocaine
• concomitant diseases: diabetes mellitus, bronchial asthma, severe liver and kidney diseases, acute thrombosis and thrombophlebitis, skin and/or soft tissue infection, infectious diseases, obliterating peripheral arteriosclerosis, diabetic angiopathy, heart defects requiring surgical intervention, fever, toxic hyperthyroidism, obesity, tuberculosis, sepsis, blood cell composition disorder, all diseases requiring bed rest, heart disease with decompensation, known hereditary thrombophilia
• period after treatment for alcohol addiction
• sedentary lifestyle
• history of acute deep vein thrombosis
• history of superficial thrombophlebitis
• history of drug or other addiction
• use of oral contraceptives or other hormonal drugs

The study data are available to all investigators in the chronic vein disease registry

From 15 March 2025 to 15 February 2026