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ADVANCES IN DERMATOLOGIC SURGERY - Editors: Jeffrey S. Dover, MD and Murad Alam, MD
Advances in Techniques for Endovenous Ablation of Truncal Veins
G. S. Munavalli, MD, MHS,1,2,3 and R. A. Weiss, MD1,3
Venous disease affects 40%-55% of the population; common symptoms include leg pain, swelling, and skin changes.1,2 It encompasses a wide spectrum of clinical manifestations, from asymptomatic spider veins overlying the ankles, to bulging branches of the greater or great saphenous vein (GSV) extending across the anterior thigh, to leg swelling and chronic ulceration of the lower medial calf. Venous insufficiency, the most common form of venous disease,2 occurs when a high-pressure leakage develops between the deep and superficial systems, or within the superficial system itself (e.g., within GSV, and the lesser or small saphenous vein (LSV), (Figure 1)), followed by sequential failure of the venous valves in the superficial veins. Venous blood escapes from its normal flow path and flows in a retrograde direction down into an already congested leg.
In 2002, the US FDA approved endovenous laser treatment as a minimally invasive method of ablating incompetent saphenous veins. This in-office procedure uses local anesthesia, thus eliminating the need for general or spinal anesthesia. Unlike the invasive processes of stripping and ligation, obtaining percutaneous access to a vein under local anesthesia and using a form of directed laser energy from the inside to shrink and seal the targeted vein allow for quick patient recovery (Figure 2).
Endovenous ablation was first performed by inserting a bipolar radiofrequency (RF) fiber into a targeted varicose or refluxing saphenous vein and heating from within.3 With more than 60,000 procedures performed worldwide since 1999, radiofrequency shrinkage of veins has become a valuable addition to treating large varicose veins resulting from saphenous reflux. Today, systems are also available that utilize various infrared wavelengths to accomplish endoluminal heating and shrinkage of saphenous trunks.
This article will focus on two types of endovenous treatment using laser: laser targeting hemoglobin (810nm, 940nm, and 980nm) and laser: laser targeting water (1320nm).
Utilization of Tumescent Anesthesia
Tumescent anesthesia, or the placement of large volumes of dilute anesthesia in a perivascular position under the direction of duplex guidance, serves several purposes:
Using the tumescent technique, sealing the GSV via the endovenous approach is a painless procedure permitting immediate post-treatment ambulation. In our experience, the incidence of deep vein thrombosis (DVT) as measured by Duplex ultrasound 3-14 days after treatment is 0%.
Endoluminal Laser Ablation Targeting Hemoglobin (810nm, 940nm, and 980nm)
Endovenous laser treatment allows delivery of laser energy directly into the blood vessel lumen in order to produce endothelial and vein wall damage with subsequent fibrosis. Various lasers are used (Table 1). The presumed target for lasers with 810nm, 940nm, and 980nm wavelengths is red blood cells. Steam bubbles are generated as blood is boiled within the lumen, resulting in thrombotic vein occlusion. Direct thermal effects on the vein wall are probably not important. The extent of thermal injury to the tissue is dependent on the quantity of blood in the lumen, the rate of pullback, and the amount of tumescent anesthesia placed around the vein.
Endoluminal Laser Ablation (1320nm) Targeting Water
In an attempt to circumvent problems associated with hemoglobin-absorbing wavelengths, the 1320nm laser was investigated for endovenous ablation beginning in 2002. US FDA clearance was achieved in September 2004 for treatment of GSV, and in August of 2005 for the obliteration of reflux in the lesser saphenous vein.
The 1320 nm CoolTouch CTEV™ (CoolTouch) uses a special conducting laser fiber coupled with an automatic pullback device pre-set to pull back at 1mm/sec (Figure 3). Tissue water is the target, and the presence or absence of red blood cells within the vessels is not relevant to the effectiveness of the procedure. This 1.32m wavelength is unique among endovenous ablation lasers in that this wavelength is absorbed only by water and not by hemoglobin (Figure 4).
Our own experience with the 1320nm device reflects a reduction in pain and bruising of 80% as compared with the 810nm device. Having treated more than 200 greater saphenous veins with the 1320nm laser, we have found the incidence of mild pain is 5%, and our success rate of vein ablation is 95% at 2 years. Goldman6 has reported a similar experience, concluding that at 6 months follow-up, a 5-watt, 1320nm intravascular laser with 1mm/sec automatic pullback, delivered through a diffusion-tip fiber, was shown to be safe and effective for treating an incompetent great saphenous vein up to 1.2 cm in diameter (Figure 5).
We believe that there is reduced pain with the 1320nm laser due to reduced vein perforations, less thrombus formation, and more uniform heating. Pain that is experienced after treatment with the 1320nm laser is probably related to heat dissipation into the surrounding tissue, rather than to vein perforations, as the incidence of bruising is extremely low. In our own unpublished studies we have found that emitting 5 watts of 1320nm radiation through a 600µ fiber moving at 1mm/sec in a 2mm-thick vein wall results in a peak temperature of the exterior vein wall of 48oC. Unfortunately, in a saphenous vein, for effective sealing and shrinkage, higher energies must sometimes be utilized. (Figure 5).
The 1320nm water-targeting device appears to be associated with less pain and bruising than 810nm, 940nm, or 980nm hemoglobin-targeting endovenous devices.
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