EVLT (Endovenous Laser Treatment) is a procedure leading to occlusion of varicose veins. It involves putting a fibre optic into a saphenous vein through a catheter. Then the laser is turned on and slowly withdrawn from the vein.
Thanks to light tissue interaction mainly thermal effects occur, the tissue is heated and the walls of the vein shrink, because of alteration of endothelium and contraction of collagen.
There are two possibilities of performing the treatment: with pulsed and continuous-wave laser operation. Using the pulsed operation also the fibre is withdrawn step by step. A better choice is to use continuous-wave laser and to withdraw the fibre also continuously, what provides more homogenous illumination of the vein, less tissue damage outside the vein and better results.