Importance of eliminating portal flow to produce large intrahepatic lesions with interstitial laser coagulation.

Background: Interstitial laser coagulation is a local treatment modality for solid tumours, such as liver metastases. Perfusion by the vascular system can transfer heat from the treatment site, thereby reducing the volume of destroyed tissue.
Methods: This effect was investigated in a pig model (n = 10). Lesions were produced in the liver with four interstitial laser fibres (5 W per fibre for 6 min): (1) with flow through the liver (n = 9); (2) with the portal vein clamped (n = 8); and (3) with both hepatic artery and portal vein clamped (n = 6). The pigs were killed and the liver was dissected; lesions were assessed macroscopically and microscopically.
Results: The volume of the lesion was significantly larger when portal flow was eliminated (30.6 versus 6.4 cm3, P < 0.001).
Conclusion: Hepatic blood flow substantially reduces the size of the lesion produced by laser coagulation. Portal flow should therefore be occluded during laser treatment to produce lesions of clinically relevant dimensions.