Metallic Stents for Treatment of Benign Biliary Obstruction: A Long-term Study Comparing Different Stents

Initial study of sediment antagonism and characteristics of silver nanoparticle-coated biliary stents in an experimental animal model

OBJECTIVE

Plastic biliary stents used to relieve obstructive jaundice are frequently blocked by sediment, resulting in loss of drainage. We prepared stents coated with silver nanoparticles (AgNPs) and compared their ability to resist sedimentation with Teflon stents in a beagle model of obstructive jaundice.

METHODS

AgNP-coated Teflon biliary stents were prepared by chemical oxidation-reduction and evaluated in an obstructive jaundice model that was produced by ligation of common bile duct (CBD); animals were randomized to two equal groups for placement of AgNP-coated or Teflon control stents. Liver function and inflammatory index were found to be similar in the two groups, and the obstruction was relieved. Stents were removed 21 days after insertion and observed by scanning and transmission electron microscopy. The AgNP coating was analyzed by energy dispersive X-ray analysis (EDXA), and the composition of sediment was assayed by Fourier-transform infrared (FTIR) spectroscopy.

RESULTS

Electron microscopy revealed a black, closely adherent AgNP stent coating, with thicknesses of 1.5-6 µm. Sediment thickness and density were greater on Teflon than on AgNP-coated stents. EDXA confirmed the stability and integrity of the AgNP coating before and after in vivo animal experimentation. FTIR spectroscopy identified stent sediment components including bilirubin, cholesterol, bile acid, protein, calcium, and other substances.

CONCLUSION

AgNP-coated biliary stents resisted sediment accumulation in this canine model of obstructive jaundice caused by ligation of the CBD.

Use of the viabil covered stent in the treatment of a benign biliary stricture with the subsequent development of acute pancreatitis

The use of bare metal stents for benign biliary strictures is typically avoided due to historically poor long-term patency. Thus, in patients who are not surgical candidates, the management of benign biliary strictures can be a frustrating process. This article describes a patient who developed a common bile duct stricture following a complex endovascular thoracoabdominal aneurysm repair. The stricture was treated with the placement of a covered metallic biliary stent; a procedure complicated by the development of acute pancreatitis.