Safety and reliability of hepatic radiofrequency ablation near the inferior vena cava: an experimental study.

PURPOSE

The heat-sink effect produced by rapid blood flow through large vessels (diameter (D) ≥ 5 mm) is an important factor that influences ablation zone size after radiofrequency ablation (RFA). Currently, however, the interactions between hepatic RFA lesions and large vessels are not well understood. The purpose of this study was to examine the effects of RFA lesions occurring near large vessels (D ≥ 5 mm) in the canine liver.

MATERIALS AND METHODS

Thirty healthy adult mongrel dogs were used, with 15 dogs randomly assigned to groups I and II. In group I, the closest distance from the tip of the RFA electrode to the large vessel (D ≥ 5 mm) was more than 20 mm; in group II, this distance to the wall of the inferior vena cava (IVC) was no more than 5 mm. RFA was performed on the liver of each dog according to standard procedures. The blood flow velocity of the IVC, the computerised tomography (CT), the pathological characteristics of the RFA lesions and procedure-related complications were examined.

RESULTS

No death or complications occurred in any dogs. Vascular walls were not affected, except for when the tips of the electrode stuck to the IVC. The coagulative necrosis region was decreased, and its shape was fusiform close to the IVC. Some normal hepatic cells were found in the necrotic region near the IVC.

CONCLUSIONS

It is both safe and feasible to perform RFA near the IVC. The shape and size of the coagulation zone should be considered when electrodes are placed in this area. Near the IVC, the size of the coagulation zone was decreased, and it was incompletely formed.