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 rad io-frequency (RF) lesion size and on potential associated biliary and porta l lesions. Radiofrequency lesions using a 1-cm exposed-tip cooled electrode were created in pig liver. Liver perfusion was modified by arterial emboli zation (n = 2), left portal clamping (n = 2), and both (n = 2). Two pigs we re used as controls. Two weeks after, control portography was performed, an imals were killed, and exvivo cholangiography was carried out. Pathological studies evaluated the lesion surface and associated portal and biliary dam ages. A mathematical regression model showed that portal occlusion increase d 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 sten oses were found in 4 cases (two arterial occlusions, one portal occlusion, and one associated occlusion). One case of partial portal vein thrombosis w as 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 les ions but is associated with a risk of biliary, portal, or parenchymal compl ications.