Radiofrequency ablation of the porcine liver with complete hepatic vascular occlusion

Background: We studied the effects of radiofrequency ablation, relative to hepatic blood flow, on the volume and shape of the resulting tissue necrosis. The extent of necrosis is directly proportional to the size of the electrode and inversely related to blood flow, Which dissipates the heat generated. Methods: Two areas of necrosis were created in each of eight porcine livers, which were assigned to four groups according to blood flow occlusion: no occlusion, occlusion of the hepatic artery and portal vein, occlusion of the hepatic veins, and complete hepatic vascular occlusion. After 25 minutes of liver reperfusion, the animals were euthanized, and the livers were examined. Results: Complete vascular occlusion resulted in the greatest area of necrosis (28.6 +/- 3.4 cm(3)), followed by occlusion of the hepatic artery and portal vein (19.2 +/- 5.9 cm(3)), occlusion of hepatic veins (14.4 +/- 2.6 cm(3)), and no occlusion (4.9 +/- 1.5 cm(3)). The volume of the necrotic areas created during complete vascular occlusion were significantly greater than those created With no occlusion, as well as those created with only the hepatic artery and portal vein occluded (P < .05). Conclusions: Complete vascular occlusion, combined with radiofrequency ablation, increases the volume of necrosis and creates a more spherical ablative area.