The safety of Habib VesOpen bipolar radiofrequency ablation catheter used in the treatment of portal vein tumor thrombus: an experimental study in miniature pig models

Objective: To explore the safety of Habib VesOpen bipolar radiofrequency ablation (RFA) catheter used in the treatment of portal vein tumor thrombus (PVTT). Methods: A total of 10 miniature pigs were randomly divided into 3 groups. Group A(n = 6): RFA of normal portal vein was directly performed; group B (n = 2): balloon obstruction of the portal vein was performed first, which was followed by RFA for the fresh thrombus in the portal vein; group C (n = 2): PVTT model was established first, and RFA of the portal vein was carried out when the portal thrombus became organized. MRI examination was employed at one, 3 and 4 weeks after RFA; the animals were sacrificed 4 weeks after RFA and pathological examination of portal vein was performed. Results: Pigs of group A received portal vein RFA under the condition of 5 W power for 0.6-3.6 min. No obvious abnormality was detected by MRI and pathological examination, which were performed one month after the treatment. In the pigs of group B, MRI performed after RFA showed that the damage of portal vein area was more serious than that in the pigs of group A; abdominal MRI examination performed at one, 3 and 4 weeks after RFA showed that the portal venous edema was gradually decreased; pathological examination at one month after RFA demonstrated serious injury of adjacent liver tissue. Pigs of group C received portal vein RFA under the condition of 7 W power for 1.5 min; no obvious edema of the ablated area was observed on MRI performed after RFA, and pathological examination revealed organized thrombus necrosis and vascular endothelial cell damage. Conclusion: When Habib VesOpen bipolar RFA catheter is used for the treatment of PVTT, the RFA power and time should be properly selected according to the severity of PVTT. In order to ensure a safer procedure, high power and short ablation time should be used when the severity of PVTT is mild, while low power and longer ablation time are recommended when the PVTT is more severe. (authors)