Endovenous laser ablation - an update

Varicose veins can be effectively treated using endovenous laser ablation (EVLA). The effectiveness of EVLA depends not only on the laser energy density in the vein but also on the continuous laser emission and the pulse mode. The current s2k guideline on the diagnosis and treatment of varicose veins contains numerous practice-relevant notes and recommendations.

It is possible to treat symptomatic varicose veins orally if surgery is not the preferred option or if postoperative problems exist, but with the exception of spider veins, all other forms of the condition are treatable with an open surgical procedure. At the same time, there are certain contraindications to surgical intervention, namely the following [2–5]:

Acute thrombosis of the deep leg vein and/or pelvic vein
Peripheral arterial occlusive disease from Fontaine stage III (except with special indication)
Known pregnancy
Moribund patient (ASA score 5)

An essential component in all endovenous procedures is ultrasound, before, during, and after surgery [6]. Endovenous thermal ablation (EVTA) has consistently demonstrated positive results in varicose great saphenous vein (GSV), small saphenous vein ( SSV), anterior accessory saphenous vein (AASV) and posterior accessory saphenous vein ( PASV), as well as in incompetent perforating veins and venous malformations [6,7]. The efficacy of the procedure is highly dependent on the laser energy density (LEED) in the vein, which should be set to a range of 60-100 J/cm vein and appropriate for the vein diameter, with success also dependent on continuous laser emission and pulse mode.

EVLA with short wavelengths and bare fiber

EVLA with short wavelengths (810-980 nm) and simple optical fiber (“bare fiber”) has been reported to cause comparatively more severe postoperative pain than laser emission of the same wavelength with jacket-tip fiber. Longer wavelengths, both with and without a modified probe, have been reported to produce less severe postoperative pain, as have radiofrequency ablation and steam ablation.

The increased discomfort is associated with frequent internal bleeding, which usually manifests as moderate bruising (31% on average; this also depends on the dressing technique [8]), but also as burns and/or necrosis (0-2.6%) and sensory nerve damage (2.4% on average) [9]. Longer wavelengths (980 nm instead of 810 nm) routinely result in much lower severity [10,11]. Postoperative hyperpigmentation with short wavelengths and bare fibers has been reported to be 0-43%, with an average of 31.3% [9], but decreasing to 0-4% five years after surgery.

With the short-wavelength and fiberless procedure, superficial venous thrombosis and periphlebitic tissue reactions have been reported at an average of 6.5%; this incidence of postoperative phlebitis has not been observed differently compared with other thermal ablation procedures [12]. Postoperative infections are rarely reported with this application; again, no measurable differences were found compared with other thermal ablation procedures [12].

Thromboembolic complications can be categorized as ablation thrombi, DVT, and pulmonary embolism. If a thrombus forms postinterventionally at the proximal junction of the treated vein, it is referred to as “EHIT” (endovenous heat-induced thrombosis); if it extends into the deep venous system, it is referred to as “PASTE” (post-ablation superficial thrombosis extension) [13]. Fortunately, such cases occur very rarely [14,15]. There are numerous recommendations for dealing with the risks of “EHIT” and “PASTE” (classification according to Dexter et al.) [13].

EVLA with longer wavelengths and modified probes

In recent years, there have been scientific publications focusing on EVLA techniques with longer wavelengths (1320-1940 nm) and modified probes. By focusing on EVLA with longer wavelengths (1470 nm) and radial fibers at continuous pull-off (1-2 mm/s), controllable and reproducible thermal effects on tissue could be achieved to a greater extent than with shorter wavelengths with “bare fiber” [16–39]. In addition, accentuated tissue damage such as carbonization or vein wall perforation, as observed with shorter wavelengths and “bare fiber”, occurs less frequently. Overall, EVLA with long wavelength and radial fiber can be considered as low risk, with this modified laser probe offering advantages over bare fiber in particular, as it causes less pain and bruising with no negative impact on the effectiveness of vein closure up to 5 years after the procedure [18,28,36].

Important outcomes at a glance

In the last 20 years, most RCTs and case studies have focused on the treatment of saphenous vein (GSV) insufficiency and saphenous vein (SSV) insufficiency, whereas much less attention has been paid to endothermic ablation of SSV; almost all long-term data refer exclusively to short-wavelength lasers (810-980 nm) and “bare fiber” [40]. Endovenous laser ablation is proving to be an effective treatment for varicose veins of the great saphenous vein [12,14]. From the time of treatment until 5 years after the procedure, a significant improvement is observed in all respects.

An analysis of different treatment modalities for GSV ablation showed that short-wavelength (810-980 nm) and “bare fiber” EVLA is inferior to radial probe EVLA [18] and EVSA (endovenous hot steam ablation) [41], although it is comparable to radiofrequency-driven segmental thermal ablation (sRFA) and bipolar radiofrequency ablation (bRFA) [42–44]. On superficial inspection, the procedure can be seen to be immediately effective, with reproducible occlusion rates of 95-100% on duplex ultrasound [42,45,46], with occlusion maintained in 85-88% of cases 4-5 years later [47,48], representing an anatomic treatment success rate comparable to that of other forms of thermal ablation procedures [41,42].

However, in the longer term, maintenance of therapeutic outcomes appears to be highly dependent on factors related to vein diameter and energy density, so success rates may decline, although results have not always been reproducible in various studies [46,49]. Compared with EVLA with longer wavelengths and radial probes, the results of all available studies show that the closure rates of the longer-wavelength form are 87.5% and 100% after observation periods of 3 months to 5 years [19]. In addition, all clinical studies show that the adverse side effects of this form of treatment and the need for dereb prevention measures are low and the convalescence period is minimal: most patients have resumed normal physical activity within 2 days.

The results of EVLA with long wavelengths (1320-1940 nm) and modified probes can be observed in a variety of studies of different forms: randomized controlled [17,18,20,21,24,30,31,34,35], prospective comparative [19,22,23,26,29], retrospective comparative [33,37], and prospective cohort studies [16,25,28,32,38].

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