Safety, efficacy, and removability of a fully covered multi-hole metal stent in a swine model of hilar biliary stricture: a feasibility study

Background and study aims Use of fully covered self-expandable metal stents (FCSEMS) for biliary drainage of malignant hilar biliary strictures is limited because of risk of cholangitis due to side branch obstruction. The aim of this study was to evaluate the safety and efficacy of unilateral placement of a multi-hole FCSEMS (FCSEMS-MH), which had a 2.5-mm hole in the center of the membrane on each cavity, in a swine model of hilar biliary stricture. Materials and methods Six female mini pigs were included in this prospective study. The hilar biliary stricture model was prepared using an endobiliary radiofrequency ablation. FCSEMS-MHs were endoscopically inserted into the peri-hilar bile duct of all the animals. Outcomes were assessed in terms of adverse events (AEs) including cholangitis, stent patency, stent migration, and endoscopic stent removability for 1 month after stenting. Results In terms of hilar biliary stricture types, two animals were of Bismuth type I and four were of type II. Technical success rate for endoscopic metal stenting was 100 % (6/6), and the functional success rate, which was evaluated 7 days after stent insertion, was also 100 % (5/5). The immediate overall AE rate was 0 %. There was no procedure-related mortality and stent migration did not occur in any animal during the 4-week stent indwelling period. Stents were removed from all six animals at 4 weeks post-stenting. Conclusion Unilateral placement of FCSEMS-MH might be safe and effect for swine hilar biliary stricture models. However, long-term follow-up and comparative studies are needed to verify the usefulness of this stent.

Self-Expanding Metallic Stents in Malignant Biliary Obstruction-Patency and Clinical Efficacy: A Prospective Study from North India Tertiary Center

ABSTRACT Background and Aims: Endoscopic insertion of self-expandable metallic stent (SEMS) is now accepted as first line modality of treatment for palliation in unresectable extra-hepatic biliary obstructive jaundice. This study was done to assess the clinical efficacy and duration of patency of endoscopically inserted metallic stent in un-resectable malignant biliary obstruction. Materials and Methods: Between 2015 to 2017, 101 patients who underwent ERCP and SEMS placement for palliation of malignant biliary obstruction were included prospectively. Main outcome measures were technical success, clinical success, mean duration of SEMS patency, clinical efficacy, rate of biliary re-intervention and survival of patients. Results: Overall technical success and clinical success was achieved in 93% and 82.2% respectively. Mean duration of SEMS patency was 109 days. Analysis in subgroup of patients classified according to site of obstruction (Hilar -68, Distal CBD-33) showed that median duration of stent patency was significantly better in distal biliary stricture (135 days vs 95 days), whereas re-intervention rates were higher in higher biliary stricture than distal stricture (41% Vs 6%). Seven patients with hilar biliary stricture suffered post-SEMS insertion cholangitis. Conclusion: SEMS placement is feasible palliative method for un-resectable malignant biliary obstruction with acceptable technical and clinical success. The duration of SEMS patency and clinical efficacy is significantly better in distal biliary stricture whereas re-intervention rate is higher in hilar biliary stricture.