Aim
Antireflux plastic biliary stents prevent duodenal biliary reflux and improve the stent patency rate. However, the efficacy of the antireflux valve in a self‐expandable metal stent (SEMS) for a malignant biliary obstruction has not been well established. We evaluated the efficacy of a SEMS with an antireflux valve using in vitro flow studies and determined the impact of reducing duodenobiliary reflux on the stent patency rate.
Methods
In vitro testing was conducted using a bile perfusion system to evaluate the antegrade and retrograde flow resistance, and to determine the ideal shape for the valve. Then, a prospective case series in humans was conducted with an adequately designed SEMS with an antireflux valve.
Results
During the study period, five patients with an unresectable non‐hilar malignant biliary obstruction underwent insertion of a SEMS with an antireflux valve. Placement of the SEMS with anantireflux valve was successful on the first attempt in all patients, and no procedure‐related complications occurred. Follow up was obtained in all cases. Serum bilirubin level did not decrease to the normal range within 1 month in four patients. Stent occlusions occurred in all four patients as a result of valve malfunctions due to sludge impaction or a clog. Therefore, the study was terminated early due to unexpected results.
Conclusion
SEMS with an antireflux valve was ineffective in patients with non‐hilar malignant biliary obstruction due to limitations on current stent technology.