Endovenous Laser Ablation (EVLA) for Treatment of Varicose Veins: A Comparison of EVLA with 1470 nm and 1940 nm Lasers

INTRODUCTION: Endovenous laser ablation (EVLA) using 1470 nm, which targets water as its chromophore, has become the standard endovenous thermal treatment for incompetent truncal veins. Recently, there has been growing interest in the use of 1940 nm, due to the greater absorption by water. This increased absorption has led to claims that, with the longer wavelength, less power is needed to achieve the same biological effect during treatment, resulting in fewer adverse post-operative sequelae. METHODS: Review of the current literature comparing 1940 nm and 1470 nm EVLA, which includes both laboratory-based and clinical studies. Reports on the use of 1920 nm were combined with those on 1940 nm. RESULTS: Increased absorption of the longer wavelength by water results in more thermal damage closer to the EVLA device. Thus, there may be an advantage to using the longer wavelength in EVLA of thin-walled veins at low power. However, in saphenous veins, which have thicker walls, there is little evidence that this different energy distribution in the vein wall makes any clinical difference. Reduced pain is likely to be due to reduced power during treatment. This is likely to result in more long-term failures of ablation using 1940 nm. CONCLUSION: There is a difference in the distribution of thermal damage in the vein wall between EVLA at 1470 nm and 1940 nm. However, there is little evidence of any clinically significant difference when used in incompetent saphenous veins. Clinical studies looking for a difference need to report the size and wall thickness of the treated vein, the power used as well as the energy per centimetre (LEED), and long-term ablation rates in addition to early post-operative pain, induration, paraesthesia and ecchymosis. Also, power loss in different laser / fibre systems and technical differences, such as those that might allow blood to remain in the vein being treated, need to be considered.