Covered vs Uncovered Metal Stents for Palliative Biliary Decompression in Inoperable Malignant Distal Bile Duct Obstruction

Inclusion Criteria: * distal bile obstruction referred for ERCP with intended palliative metal stent placement for palliation of jaundice * 18 years of age or older * serum bilirubin \> 2mg/dL Exclusion Criteria: * prior endoscopic or percutaneous biliary drainage * post-surgical anatomy * primary site of biliary obstruction involving the common hepatic duct or hilum * tumor involving gastric outlet, duodenum, or ampulla either precluding endoscopic access to the papilla or otherwise preventing endoscopic biliary cannulation