Long-term results of temperature-controlled endobiliary radiofrequency ablation in a normal swine model

Background and Aims Endobiliary radiofrequency ablation (EB-RFA) is a new adjunctive method for biliary drainage restoration. However, a concern remains about long-term adverse events of this procedure, such as biliary stricture, perforation, and hemorrhage. Therefore, we aimed to assess the long-term effects of in vivo EB-RFA in a swine model. Methods Six mini-pigs were divided into 2 groups: 10-W/33-mm EB-RFA and 7-W/18-mm EB-RFA. Endoscopic retrograde cholangiography–guided temperature controlled EB-RFA (80°C, 7-10 W, 120 seconds) was performed. After 28 days all mini-pigs underwent follow-up ERC and were killed to assess the long-term effects of EB-RFA. Results All mini-pigs developed biliary stricture (median length, 10.5 mm; range, 6-15) with jaundice (total bilirubin, 5.84 mg/dL; range, 4.3-9.2) and purulent bile at 1 month after EB-RFA. A significant difference was found in the length of stricture on cholangiogram between the 10 W/33-mm and 7 W/18-mm EB-RFA groups (median, 14 vs 6 mm; P = .034); however, no differences were found in the width of the stricture and laboratory findings. Histologic examination revealed marked thickening of bile duct with severe damage of whole layers replaced with reactive myofibroblastic proliferation, dense collagen laydown, chronic and acute inflammation, and fat necrosis. However, long-term adverse events, such as perforation or hemorrhage, were not found. Conclusions As a long-term result of EB-RFA, segmental biliary stricture with cholangitis develops in proportion to the power/length of the RFA electrode. Therefore, biliary stents should be placed to maintain biliary drainage after EB-RFA.