Endoscopic stenting of a fully covered self-expandable metal stent with a hole in each cavity in malignant hilar biliary obstruction: A preclinical proof-of-concept study and initial human experience

Background and Aim Stent placement for biliary drainage in patients with malignant hilar biliary obstruction (MHBO) has been a topic of long-standing debate, and the best approach remains controversial. Therefore, we aimed to evaluate the efficacy, safety, and removability of multi-hole fully covered self-expandable metal stents (MH-FCSEMSs) in a preclinical experiment using swine hilar bile duct obstruction (HBDO) models and to assess the feasibility and safety of stent placement in patients with MHBO. Methods Three minipigs underwent endoscopic retrograde cholangiopancreatography (ERCP)-guided endobiliary-radio frequency ablation (EB-RFA) to establish Bismuth type II hilar bile duct stenosis models. Four weeks after EB-RFA, 10 mm-diameter and 4 cm-length MH-FCSEMSs were endoscopically inserted into the left intrahepatic bile duct of the models. Stent patency and migration, as well as adverse events including cholangitis and endoscopic stent removability, were assessed three months after stent placement. Additionally, clinical applications of MH-FCSEMS were performed in two patients with MHBO to determine feasibility, safety, and stent patency. Results MH-FCSEMSs were successfully inserted into the left main intrahepatic bile duct and common hepatic duct of the models under ERCP in all three animals without any technical difficulties. Cholangiograms performed 12 weeks after MH-FCSEMS placement showed no stent migration, and all were successfully removed from the animal models. The functional success rate, defined as a decrease in serum total bilirubin level of more than 50% at 12 weeks after stent placement, was 100%. Moreover, MH-FCSEMSs were successfully inserted in two patients with hilar cholangiocarcinoma. The procedures were technically feasible, and no major periprocedural complications were noted. Conclusion The preliminary long-term results of both preclinical and clinical pilot studies suggest that endoscopic biliary drainage using MH-FCSEMS may be a safe and effective treatment option for stenting and stent revision in the management of HBDO. Further studies comparing clinical outcomes to those of MH-FCSEMSwithout multi-hole in malignant hilar biliary obstruction will be needed to verify the clinical benefits.