Radio-frequency tissue ablation of the liver: Effects of vascular occlusion on lesion diameter and biliary and portal damages in a pig model

The aim of this study was to assess the effect of vascular occlusion on radio-frequency (RF) lesion size and on potential associated biliary and portal lesions. Radiofrequency lesions using a 1-cm exposed-tip cooled electrode were created in pig liver. Liver perfusion was modified by arterial embolization (n = 2), left portal clamping (n = 2), and both (n = 2). Two pigs were used as controls. Two weeks after, control portography was performed, animals were killed, and exvivo cholangiography was carried out. Pathological studies evaluated the lesion surface and associated portal and biliary damages. A mathematical regression model showed that portal occlusion increased by 43 mm(2) (+40 %) the surface of RF lesions, arterial occlusion by 135 mm(2) (+126 %), and associated occlusion by 466 mm(2) (+435%). Biliary stenoses were found in 4 cases (two arterial occlusions, one portal occlusion, and one associated occlusion). One case of partial portal vein thrombosis was found in one case of portal occlusion and resolved at 2 weeks. Ischemic damages adjacent to RF lesions were found in cases of combined occlusions. The reduction of liver perfusion increases significantly the size of RF lesions but is associated with a risk of biliary, portal, or parenchymal complications.