You are in: eMedicine Specialties > Dermatology > DISEASES OF THE VESSELS Varicose Veins Treated With Radiofrequency Ablation TherapyArticle Last Updated: Sep 29, 2005AUTHOR AND EDITOR INFORMATIONSection 1 of 10
  Author: Craig F Feied, MD, FACEP, FAAEM, FACPh, Professor of Emergency Medicine, Georgetown University School of Medicine; General Manager, Microsoft Enterprise Health Solutions Group Craig F Feied is a member of the following medical societies: American Academy of Emergency Medicine, American College of Emergency Physicians, American College of Phlebology, American College of Physicians, American Medical Association, American Medical Informatics Association, American Venous Forum, Medical Society of the District of Columbia, Society for Academic Emergency Medicine, and Undersea and Hyperbaric Medical Society Coauthor(s): Robert Weiss, MD, Associate Professor, Department of Dermatology, Johns Hopkins University School of Medicine; Margaret Weiss, MD, Assistant Professor, Department of Dermatology, Johns Hopkins University School of Medicine Editors: Désirée Ratner, MD, Director of Dermatologic Surgery, George Henry Fox Assistant Clinical Professor, Department of Dermatology, Columbia Presbyterian Medical Center, New York Presbyterian Hospital; David F Butler, MD, Professor of Dermatology, Texas A&M University College of Medicine; Director, Division of Dermatology, Scott and White Clinic; Director Dermatology Residency Training Program, Scott and White Clinic; John G Albertini, MD, Consulting Staff, Dermatologic Surgery, The Skin Surgery Center; Glen H Crawford, MD, Assistant Clinical Professor, Department of Dermatology, University of Pennsylvania School of Medicine; Chief, Division of Dermatology, The Pennsylvania Hospital; William D James, MD, Paul R Gross Professor of Dermatology, University of Pennsylvania School of Medicine; Vice-Chair, Program Director, Department of Dermatology, University of Pennsylvania Health System Author and Editor Disclosure Synonyms and related keywords: RFA, RF ablation, endothermal radiofrequency catheter treatment, closure procedure, RF-mediated endovenous occlusion, endovascular diathermic vessel occlusion INTRODUCTIONSection 2 of 10
  Venous insufficiency resulting from superficial reflux because of varicose veins is a serious problem that usually progresses inexorably if left untreated. When the refluxing circuit involves failure of the primary valves at the saphenofemoral junction, treatment options for the patient are limited, and early recurrences are the rule rather than the exception. In a traditional surgical approach, ligation and division of the saphenous trunk and all proximal tributaries are followed either by stripping of the vein or by avulsion phlebectomy. Proximal ligation requires a substantial incision at the groin crease. Stripping of the vein requires additional incisions at the knee or below and is associated with a high incidence of minor surgical complications. Avulsion phlebectomy requires multiple 2- to 3-mm incisions along the course of the vein and can cause damage to adjacent nerves and lymphatic vessels. Radiofrequency endovenous ablation, a newer procedure, is less invasive than surgery and has a lower complication rate. The procedure is well tolerated by patients and produces good cosmetic results. Excellent clinical results are seen at 4-5 years, but the long-term efficacy of the procedure is not yet known. TECHNOLOGYSection 3 of 10
Radiofrequency endovenous ablation works by thermal destruction of venous tissues. Electrical energy passes through the tissues in the form of high-frequency alternating current and is converted into heat, which causes irreversible localized tissue damage. Radiofrequency energy is delivered through a special catheter with deployable electrodes at the tip; the electrodes touch the vein walls and deliver energy directly into the tissues without coagulating blood. Energy delivery Special thermocouples monitor the temperature at the deployable electrodes. During the procedure, the temperature within the vessel wall is limited to 85°C to avoid thermal injury to the surrounding tissues or carbonization of the vein wall. As the vein is denatured by heat, it contracts around the catheter, lowering impedance and reducing heat generation. If excessive debris builds up on the catheter tip, a sensor that monitors the impedance of the circuit shuts down the system. As the heat causes the vessel to shrink in the treated area, the catheter is gradually withdrawn along the course of the vein until the entire vessel has been treated. Image 1 demonstrates a schematic diagram of the process. Catheters Many different radiofrequency ablation catheters are available for medical applications, but the Closure catheter, manufactured by VNUS Medical Technologies, is the only commercially available radiofrequency ablation system designed for venous ablation. Image 2 shows the Closure console, and Image 3 shows 2 sizes of radiofrequency ablation catheters. HISTOLOGIC FINDINGSSection 4 of 10
Immediately after treatment, biopsy specimens show a significant reduction in the size of the vein lumen, with denudation of endothelium, thrombus formation, thickened vessel walls, loss of collagen birefringence, and inflammatory changes. The zone of thermal damage is limited to 2 mm beyond the point of contact with the electrodes. In more than 90% of patients, biopsy specimens demonstrate complete occlusion of the vein lumen 6 weeks after treatment. The lumen is completely ablated in most areas, with some portions of the vessel demonstrating a small residual lumen containing organized fibrous thrombi. Birefringence is present, and new collagen growth is evident. TECHNIQUESection 5 of 10
Present radiofrequency ablation catheters cannot be easily passed along a tortuous superficial vein; therefore, the procedure is principally of use in the treatment of truncal varicose veins, such as the greater saphenous vein, with saphenofemoral incompetence. Preprocedure Ultrasonography is used to confirm and map all areas of reflux and to trace the path of the refluxing greater saphenous trunk from the saphenofemoral junction down the leg to the upper part of the calf. An appropriate entry point is selected just above or just below the knee, at a point permitting cannulation of the vessel with a 16-gauge needle introducer. The vein, the saphenofemoral junction, and the anticipated entry point are marked on the skin with a surgical marker. Procedure The leg is prepared and draped, and a superficial local anesthetic agent is used to anesthetize the site of cannulation. Needle puncture of the vessel is guided by ultrasonography. The Seldinger technique is used to place a guidewire into the vessel, and an introducer sheath is passed over the guidewire, which is removed. The Closure catheter is passed through the sheath, and the tip is advanced to the saphenofemoral junction under ultrasonographic visualization. With ultrasonographic guidance, a local anesthetic agent is injected into the tissues surrounding the greater saphenous vein within its fascial sheath. The anesthetic is injected along the entire course of the vein from the catheter insertion point to the saphenofemoral junction. In most patients, 60-120 mL of lidocaine 0.25-0.5% is sufficient both to anesthetize the vessel and to compress the vessel. Note the importance of delivering the anesthetic agent in the correct intrafascial location, with a volume sufficient to compress the vein and dissect it away from other structures along its entire length. Ultrasonography is used to position the catheter tip at the level of the terminal valve of the saphenofemoral junction, and the catheter electrodes are deployed. The electrodes should be just distal to the valve cusps of the terminal or subterminal valve, but the catheter must not extend into the femoral vein because injury to the femoral vein may cause deep vein thrombosis. When the console is switched on and the test mode is activated, the baseline impedance should be 250-300 ohms and the baseline temperature should be 32-37°C. When radiofrequency energy is applied, the thermocouple temperature should rise to 80-85°C within 10-15 seconds. If the temperature does not rise quickly, a malpositioned catheter tip should be strongly suspected. After the temperature reaches 85°C and remains constant for 15 seconds, the catheter tip is slowly withdrawn at a rate of approximately 1 cm per minute (1 mm every 6 seconds). After the catheter tip is 4 cm below the saphenofemoral junction, the rate of withdrawal is increased to approximately 2.5 cm per minute (1 mm every 2-3 seconds). If the catheter tip enters an area of the branch point at which the vein is particularly dilated, the temperature drops quickly. In this case, the tip is left in place until the temperature rises to 85°C and remains constant for 5 seconds, after which the tip is withdrawn again as before. The patient rarely experiences a sudden heat sensation if the catheter tip reaches an area with an adherent nerve. If this happens, the catheter is rapidly withdrawn, approximately 1 cm past that point, to minimize the risk of nerve injury. When the catheter reaches the introducer sheath in the distal vein, the impedance rises abruptly and the console automatically shuts off. Postprocedure Posttreatment sonograms confirm the contraction of the vessel and the absence of flow along the entire length of the treated vessel. If persistent flow is observed, the procedure may be repeated immediately, provided the catheter can still be easily passed along the vessel to the desired site of treatment. FOLLOW-UP CARESection 6 of 10
Compression is of vital importance after any venous procedure. Compression is effective in reducing postoperative bruising and tenderness, and it can also reduce the risk of venous thromboembolism in both the treated leg and the untreated leg. A class II (30- to 40-mm Hg gradient) compression stocking is applied to the treated leg, and, if the patient is willing, it is also applied to the untreated leg. Bed rest and lifting of heavy objects are forbidden, and normal activity is encouraged. The patient is reevaluated 3-7 days after the operation, at which time duplex sonograms should demonstrate a closed greater saphenous vein and no evidence of thrombus in the femoral, popliteal, or deep veins of the calf. At 6 weeks, an examination should reveal clinical resolution of truncal varices, and an ultrasonographic evaluation should demonstrate a completely closed vessel and no remaining reflux. If any residual open segments are noted, sclerotherapy is performed under ultrasonographic guidance. For patient education resources, visit eMedicine's Circulatory Problems Center. Also, see eMedicine's patient education article Varicose Veins. COMPLICATIONSSection 7 of 10
Reported complications of the procedure are rare. Local paresthesias can occur from perivenous nerve injury but are usually temporary. Thermal injury to the skin was reported in clinical trials when the volume of local anesthetic was not sufficient to provide a buffer between the skin and a particularly superficial vessel, especially below the knee. Pregression of thrombus from local superficial phlebitis has occasionally been observed when compression was not used. The greatest current area of concern is deep vein thrombosis, with one 2004 study documenting deep vein thrombus requiring anticoagulation in 16% of 73 limbs treated with a radiofrequency ablation procedure. OUTCOMESSection 8 of 10
Although the procedure is relatively new, published results show a high early success rate with a very low subsequent recurrence rate up to 5 years after treatment. Early and mid range results are comparable to those obtained with other more invasive surgical techniques. Patient satisfaction is high, with 95% of patients reporting that they would recommend the procedure to a friend. MULTIMEDIASection 9 of 10
REFERENCESSection 10 of 10
Varicose Veins Treated With Radiofrequency Ablation Therapy excerpt Article Last Updated: Sep 29, 2005 | |||||||||||||||||||||
