Linear Endovenous Energy Density (LEED) Should Always be Quoted with the Power Used, in Endovenous Thermal Ablation – Results from an In-Vitro Porcine Liver Model Study.

Introduction: Endovenous thermal ablation (EVTA) is the first line treatment of symptomatic truncal venous reflux. Linear Endovenous Energy Density (LEED) is the measure of energy used per cm of treated vein. The rate of application of energy influences thermal spread and tissue damage. However, time is absent from LEED. The aim of this study was to test the effect of time during EVTA in a validated in-vitro model.

Methods: We used a bipolar radofrequency catheter and the previously validated porcine liver model to assess any thermal effects. We used combinations of power and pullback speeds giving LEEDs of 40, 60, 80 and 100 J/cm. High-resolution digital images of the ablation tracts were taken. Each setting was repeated 5 times. Thermal spread was measured using digital measuring software, tissue carbonisation assessed by a defined scale and any device-tissue sticking during treatment was recorded.

Results: LEED was significantly positively correlated to thermal spread (r(20) = .86, P < .00001) and carbonisation of the tissue (r(24) = .82, p < .00001). Power was significantly correlated with carbonisation (r(24) = .50, p = .009) but not with thermal spread (r(20) = .34, p = .121). Pullback had no significant correlations with thermal spread or carbonisation. Catheter sticking was only found when the power was >= 15 W or the LEED was >= 80 J/cm.

Conclusion: LEED is a good measure of EVTA but does not take into account the time of energy application to tissue. Power, which does include time, has a significant correlation with tissue carbonisation, and is also important in device-tissue sticking. Pullback has no significant correlation to any tissue effects. Quoting the LEED alone in reporting EVTA is inadequate. It is essential to include the power used when LEED is quoted.

Nielsen, A. G., Croucher, A. A., Muschamp, S. D., Losty, E., Worthington, T., Kiely, M. J., & Whiteley, M. S. (2022, November 24). Linear Endovenous Energy Density (LEED) Should Always be Quoted with the Power Used, in Endovenous Thermal Ablation – Results from an In-Vitro Porcine Liver Model Study. https://doi.org/10.31219/osf.io/v8znr