In vivo evaluation of a new bioabsorbable self-expanding biliary stent

Background: Bioabsorbable stents may offer advantages for the treatment of benign and malignant biliary strictures, including large stent diameter, decreased biofilm accumulation and proliferative changes, elimination of the need for stent removal and imaging artifacts, and prospects for drug impregnation. However, suboptimal expansion has hampered prior iterations. A new bioabsorbable biliary stent (BioStent) was evaluated in a porcine model. Methods: BioStents were placed in 8 animals for long-term follow-up. The following were evaluated: accuracy and ease of delivery and deployment, radial expansion, and radiologic visualization. Stent function and bio-tolerance were assessed by cholangiography, serum bilirubin, and necropsy for histopathology performed in pairs at 2, 49 6, and 12 months. Results: Stents were delivered without sphincterotomy and were deployed easily, accurately, and with good immediate stent expansion and radiographic visualization. On follow-up, all stents were fully expanded and serum bilirubin levels remained within the normal range. Although there was no clinical evidence of biliary obstruction, filling defects were common at cholangiography. On histopathologic evaluation, there was neither bile duct integration or proliferative change. Conclusions: The BioStent bioabsorbable biliary stent, modified with axial runners, can be effectively deployed endoscopically, is self-expanding, is visualized radiographically, and remains patent up to 6 months. There was no bile duct integration or proliferative change, which are potential advantages. Stent occlusion and migration remain concerns.