Evaluation of endovenous radiofrequency ablation and laser therapy with endoluminal optical coherence tomography in an ex vivo model

Abstract

In our ex vivo cow foot model, eOCT is able to reproduce normal vein wall structures and endovenous acute thermal alterations, such as tissue ablation and vessel wall perforations. Endovenous eOCT images can also be analyzed quantitatively to measure media thickness or vein lumen diameter. Endovascular OCT could become a valuable alternative tool for morphologic investigation of tissue alterations after endovenous thermal procedures.

Randomized clinical trial of VNUS® ClosureFAST™ radiofrequency ablation versus laser for varicose veins

“…One possible explanation for the reduced pain scores following RFA may be that the controlled heating and segmental ablation technique of VNUS  ClosureFAST TM reduces the number of vein wall perforations and the extravasation of blood into the tissues 26,27 ; this has been shown to occur after use of the 980-nm laser in animal models 26 and in humans 28 .…”

Endovenous laser therapy – application studies and latest investigations

“…In endovenous radiofrequency ablation (VNUS Closure) reproducible, defined thermal damage to tissue can already be produced through the implementation of feed-back mechanisms with automatic generator-steered regulation of energy density and standardized treatment protocols. By contrast, using ELT with the bare-fiber technique the effects on tissue are clearly very varied [18,28]. Because of the use of differing wavelengths, different pull-back protocols and different energy densities, ELT can hardly be standardized.…”

“…Applying a high amount of fluence rate to the tissue (FR > 1000 W/cm) and exceeding the ablation threshold of the tissue, local perforations could occur [14,28,29]. Such tissue effects could be observed during bare fibre light application, especially in cases the fibre tip is contact to the tissue.…”

“…Using bare fibre tip technique the mechanism of heat induction and heat transfer to the vessel target is still not investigated in detail. Thus, reducing side effects and clarification of the underlying mechanism in mind, an improved and reproducible light energy application to the vessels wall is requested [14,28,29].…”

“…Variations in the laser wavelength and power settings result in different temperature levels and thermal alterations. In addition the light application technique, more precisely the light distribution within the vessel, could influence the type of response as well, for example vessel wall perforation could be observed in case of bare fibre technique in combination with special treatment protocols [14,28,29]. With respect to this, the blood as the primary medium around the laser fibre tip influences the mechanism and the process as well.…”