Optical-thermal mathematical model for endovenous laser ablation of varicose veins.

Endovenous laser ablation (EVLA) is successfully used to treat varicose veins. However, the exact working mechanism is still not fully identified and the clinical procedure is not yet standardized. Mathematical modeling of EVLA could strongly improve our understanding of the influence of the various EVLA processes.

Endovenous simulated laser experiments at 940 nm and 1470 nm suggest wavelength-independent temperature profiles.

Background: EVLA has proven to be very successful, but the optimum methods for energy delivery have still not been clarified. A better understanding of the mechanism of action may contribute to achieving a consensus on the best laser method and the most effective use of laser parameters, resulting in optimal clinical outcomes, maintaining high success rates with minimal adverse events. The aim of this study is to assess the impact of wavelength, pullback speed and power level on the endovenous temperature profile in an experimental setting.

The heat-pipe resembling action of boiling bubbles in endovenous laser ablation.

Endovenous laser ablation (EVLA) produces boiling bubbles emerging from pores within the hot fiber tip and traveling over a distal length of about 20 mm before condensing. This evaporation-condensation mechanism makes the vein act like a heat pipe, where very efficient heat transport maintains a constant temperature, the saturation temperature of 100 degrees C, over the volume where these non-condensing bubbles exist. During EVLA the above-mentioned observations indicate that a venous cylindrical volume with a length of about 20 mm is kept at 100 degrees C.