Radiofrequency-induced thermotherapy (RFiTT) in a porcine liver model and ex vivo great saphenous vein.

AIMS: To investigate the thermal spread achieved in porcine liver when using an optimised radiofrequency ablation protocol and correlate findings with the effects seen in ex vivo great saphenous vein (GSV), in order to justify clinical use with the new treatment protocol.

MATERIAL AND METHODS: Porcine liver and GSV sections were treated with radiofrequency-induced thermotherapy (RFiTT) using the following settings: 20 W at 1 s/cm (linear endovenous energy density; LEED 20 J/cm), 18 W at 1 s/cm (LEED 18 J/cm), 18 W at 3 s/cm (LEED 54 J/cm), 6 W interrupted pull-back 6 s stationary every 0.5 cm (LEED 72 J/cm). Thermal spread in the liver was measured via digital imaging. GSV sections were sent to an independent laboratory for histological analysis. Previous work suggests a thermal spread of >0.65 mm in liver correlates with transmural thermoablation of a GSV.

RESULTS: Parameters giving a LEED of 72 J/cm produced the best results, with a clear transmural effect in the GSV and maximal thermal spread of 1.65 mm, without excessive thermal damage or carbonisation in the ablation tract.

CONCLUSIONS: Our porcine liver model correlated well with histological findings and was representative of the thermoablative effects observed in the GSV wall treated with RFiTT. Clinical investigations are now being carried out to investigate the efficacy of this protocol in the clinical setting.