Efficacy and safety of a self‐expandable stent‐based endobiliary radiofrequency ablation: A preclinical study

Abstract

The temperature‐controlled, bipolar self‐expandable stent (SES)‐based radiofrequency ablation (RFA) system represents a novel endobiliary RFA approach; however, its efficacy and safety must be verified before clinical application. The study aimed to investigate the efficacy and safety of SES–RFA in a porcine common bile duct (CBD) model. Ablation ranges were investigated using ex vivo porcine liver according to radiofrequency energy and time. For the in vivo study, radiofrequency parameters were set at 20 W for a 20‐mm electrode and 25 W for a 25‐mm electrode at 70°C for 120 s. Twelve pigs underwent endoscopic‐guided SES–RFA using either electrode ( n  = 6 each). Animals were randomly euthanized at 24 h or 2 weeks after SES–RFA ( n  = 3 per group). The RFA‐treated CBDs were evaluated using cholangiography, cholangioscopy, hematology, histology, and immunohistochemistry. The SES–RFA system was successfully deployed and retrieved through‐the‐scope without device failure. All animals survived until the study endpoint without RFA‐related adverse events, including ductal perforation, contrast leakage, or hematoma. Hepatobiliary levels of alkaline phosphatase, aspartate aminotransferase, alanine aminotransferase, and gamma‐glutamyl transferase were significantly higher at 2 weeks than at 24 h post‐SES–RFA (all p < 0.05). Ablation ranges and degree of mucosal damage, including collagen and TUNEL‐positive deposition, were significantly increased at 2 weeks than at 24 h (all p < 0.05). The temperature‐controlled bipolar SES–RFA system effectively and safely produced circumferential coagulative necrosis without ductal perforation in the porcine CBD. The system may be used for managing unresectable malignant biliary obstruction in anatomically challenging regions where conventional RFA is difficult to use.