Varicose Veins: Endovenous Laser Treatment

Thrombus formation using endovenous lasers: an in vitro experiment

“…Higher energy (LEED) has been proposed to avoid the creation of thrombus, which can re-canalize and cause treatment failure. 7 Results of these experiments provide support for the theory that pulsed lasers generate less coagulum when compared with CW lasers implying that pulsed lasers also create less thrombus during ELA. Of these pulsed lasers, only the 1320 nm Nd:YAG is commercially available, and for this reason its settings were investigated more extensively than the other pulsed lasers (Nd:YAG 1064 nm and THOYAG 2100 nm).…”

“…Prototype-modified tip fibres were included in this study to model commercially available fibres with fibre-centring devices that have been shown to reduce vein perforations by minimizing contact with the vein wall during treatment. 7,8 Experiment details can be seen in Figures 1 and 2. In vivo procedures utilized a constant fibre withdrawal velocity to evenly distribute laser energy 3 using a pullback mechanism (cardiovascular device used to withdraw a catheter from the vessel lumen at constant, precise rates).…”

“…Along with other methods such as surgical ligation/stripping, sclerotherapy and radio frequency ablation, pulsed and continuous wave (CW) mid-infrared lasers are effectively used to treat incompetent great saphenous veins via thermal coagulation of the vein lumen (often referred to as endovenous laser ablation or ELA). 1–10 ‘Soft Thrombus’ in the context of endovenous thermal vein closure is distinguished from the hard carbonized deposits that are frequently found on the fibre tip after it is withdrawn from the vein. The soft thrombus is very fragile and will be wiped off of the fibre tip when the vein closes around it or when the fibre is withdrawn.…”

“…Carbonized blood has been observed on fibre tips at temperatures in excess of 1000°C, with a variety of laser wavelengths. 5,7,12 This carbonized blood has been found to reduce the transmission of light to the laser target, thus reducing procedure efficacy. 7,12…”

Effect of spatial light distribution on the thermal response of vascular tissue

“…Reportedly, blood around the fiber tip is the main cause to circumvent the light transmission to the vein wall and to induce recanalization due to thrombotic effects and steam bubble generation [26]. In clinical situations, the blood inside the vein is often removed and even emptied by using a Trendelenburg position, and tumescent solution is then injected around the vein in order to reduce pain, to protect the perivenous tissue by cooling, and to exert compression around the vein [27,28]. Recently, F.L.…”