Introduction: Immediately adjacent to large hepatic veins, tumour ablation by radiofrequency or electrolysis may be impaired by heat or current sink effects. Ablation may also cause vessel injury and thrombosis. The aim of this study was to evaluate the safety and efficacy of radiofrequency and electrolytic ablative techniques adjacent to large hepatic veins.
Methods: Electrolytic and radiofrequency zones of ablation were created adjacent to hepatic veins in large white pigs. After 72 h the zones of ablation created were examined histologically for (a) the extent of tissue necrosis up to the vessel and (b) the presence of intimal damage and mural thrombus in the veins.
Results: An unexpected complication of electrolysis near large veins was cardiac tamponade. This current related phenomenon could easily be avoided. In seven of nine electrolysis zones of ablation necrosis was completely adjacent to the vessel wall, but in only four of seven radiofrequency zones of ablation. All zones of ablation were associated with intimal necrosis, and most with mural thrombosis.
Conclusions: Ablation of hepatic tumours by radiofrequency and electrolysis is unreliable adjacent to hepatic veins. Both techniques are associated with mural thrombus formation, and so risk thrombo-embolic complication. These ablative modalities are not recommended for zones of ablation adjacent to hepatic veins.