To evaluate complications after radiofrequency ablation (RFA) of the porcine liver through portal vein penetration.

Twelve pigs were divided into two groups. In group I (n=11) animals, the portal veins were directly penetrated with an electrode, and in the group II (n=16) animals, the portal veins were located within the expected ablation area. For the group I pigs, RFA were performed for seven minutes after complete portal vein passing of the exposed tip. Gray-scale and Doppler ultrasonography, and CT were performed before and after RFA on the procedure day, and on day two. If any complications were found, the same studies were performed at day seven. We analyzed the presence and extent of thrombotic occlusion, the vascular stricture, the arterioportal shunt, and the presence of an intra-abdominal hemorrhage. We applied Fisher's exact test to compare the complication rate between the two groups;, a value was considered statistically significant if the p-value was less than 0.05.

In the group I animals (n=11), three had complete thrombotic occlusion of the portal vein. Among these three animals,, one had a segmental infarction, and one animal showed a partial occlusion. In the group II animals (n=16), complications were not identified. Statistical analysis revealed the complication rate of group I was significantly higher than that of group II (p=.019).

The portal vein occlusion rate was significantly higher in the portal vein penetrating group than in the non-penetrating group.