What is the procedure for endovenous thermal ablation (EVA) in a patient with symptomatic varicose veins?

Endovenous Thermal Ablation Procedure

Overview of the Procedure

Endovenous thermal ablation (EVA) is performed as an outpatient procedure under local tumescent anesthesia, using ultrasound guidance to deliver thermal energy directly into the incompetent saphenous vein, causing immediate vein wall damage and subsequent fibrotic occlusion. 1, 2

Pre-Procedure Preparation

• Ultrasound mapping is performed to identify the exact location of the incompetent vein, measure vein diameter, document reflux duration, and assess the deep venous system for patency 1, 2
• The patient is positioned supine or in slight Trendelenburg position to facilitate venous access 3
• The skin entry site is selected, typically at the knee level for great saphenous vein (GSV) treatment or at the calf for small saphenous vein (SSV) treatment 4

Tumescent Local Anesthesia Administration

• Tumescent local anesthesia (TLA) is administered using ultrasound guidance to create a fluid compartment around the target vein, providing anesthesia, thermal protection for surrounding tissues, and compression of the vein 3
• A standard volume of 10-12 ml/cm of tumescent solution is infiltrated into the perivenous space along the entire length of the vein to be treated 3
• For bilateral GSV treatment, the mean total TLA volume is approximately 931 ml; for unilateral treatment, approximately 425 ml 3
• The tumescent solution creates a protective barrier that reduces the risk of thermal injury to surrounding nerves, muscles, and skin 1, 3

Venous Access and Catheter Placement

• Ultrasound-guided percutaneous access is obtained using the modified Seldinger technique, typically 2-5 cm below the saphenofemoral junction for GSV or below the saphenopopliteal junction for SSV 1, 2
• A small skin incision (2-3 mm) is made, and the vein is punctured under direct ultrasound visualization 4
• A guidewire is advanced through the needle, followed by a catheter sheath 4
• The laser fiber or radiofrequency catheter is advanced through the sheath to the target position, typically 1-2 cm from the saphenofemoral or saphenopopliteal junction 1, 4
• Ultrasound confirmation of catheter tip position is mandatory before energy delivery to avoid treating the deep venous system 1, 2

Energy Delivery

For Laser Ablation (EVLA)

• Laser energy is delivered continuously as the fiber is slowly withdrawn at a controlled rate, typically 1-2 mm per second 4, 5
• Modern wavelengths >1900 nm (such as 1940 nm) allow for lower power settings (average 4.5 watts) and linear energy density (LEED) of approximately 41 J/cm 5
• The laser causes immediate vein wall damage through direct thermal injury and steam bubble formation 6, 5

For Radiofrequency Ablation (RFA)

• Radiofrequency energy is delivered in segmental fashion as the catheter is withdrawn in 7-cm increments 2, 4
• The catheter heats the vein wall to approximately 120°C, causing collagen contraction and vein wall shrinkage 2
• Treatment cycles last 20 seconds per segment 2

Immediate Post-Procedure Management

• Ultrasound evaluation is performed immediately after energy delivery to confirm complete vein occlusion and assess vein wall thickness 4
• The catheter and sheath are removed, and manual pressure is applied to the puncture site 4
• A compression dressing is applied, and the patient is fitted with compression stockings (20-30 mmHg) 1, 2
• Patients mobilize immediately after the procedure and are discharged the same day 4, 6

Adjunctive Procedures

• Ambulatory phlebectomy may be performed simultaneously through 2-3 mm stab incisions to remove large varicose tributaries 1, 2
• Ultrasound-guided foam sclerotherapy can be administered to treat smaller tributary veins (2.5-4.5 mm diameter) during the same session 1, 7
• The combination approach addresses both truncal reflux and symptomatic varicose branches in a single treatment session 1, 7

Technical Success Rates

• Endovenous thermal ablation achieves 91-100% occlusion rates at 1-year follow-up for appropriately sized veins (≥4.5 mm diameter) 1, 2, 4
• At 2-year follow-up, occlusion rates remain high at 95.9% for laser ablation 5
• Long-term follow-up at mean 6.7 years demonstrates 86% overall satisfaction with sustained symptom relief and absence of varicosities 4

Post-Procedure Surveillance

• Early duplex ultrasound (2-7 days post-procedure) is mandatory to detect endovenous heat-induced thrombosis (EHIT) and assess initial treatment success 1, 2
• Follow-up ultrasound at 1 month confirms complete vein occlusion 4, 5
• Long-term surveillance at 6 months, 1 year, and 2 years documents durability of treatment 4, 5

Complications and Risk Mitigation

• Deep vein thrombosis occurs in 0.3% of cases and pulmonary embolism in 0.1% 1, 2
• Approximately 7% risk of temporary nerve damage from thermal injury, though most resolves spontaneously 1, 2
• Common minor complications include phlebitis, bruising, and temporary skin discoloration 1
• Tumescent anesthesia provides thermal protection and significantly reduces the risk of skin burns and nerve injury 3