Clinical advantages of a metal stent with an S-shaped anti-reflux valve in malignant biliary obstruction

Abstract

BACKGROUND AND AIM: Transpapillary stent insertion is the standard treatment for palliating malignant biliary obstruction. However, luminal occlusion often occurs due to sludge formation, tumor ingrowth, or tumor overgrowth. Currently, influx of duodenal contents by duodenobiliary reflux is considered a mechanism of stent obstruction. The aim of the present study was to evaluate the efficacy and safety of a metal stent with an anti-reflux valve in distal malignant biliary obstruction. METHODS: Thirty-two patients diagnosed with unresectable malignant biliary obstruction were enrolled. This trial was conducted at two tertiary hospitals in Korea from June 2009 to June 2011. An uncovered metal stent (M.I.Tech) with an S-type anti-reflux valve was placed. RESULTS: A total of 32 patients were enrolled. The technical success rate of stent insertion was 100%. The median duration of stent patency was 14.4 months. Stent occlusion occurred in 11 cases, which was caused by sludge formation in six cases, tumor ingrowth in four cases, and migration of the stent membrane in one case. During the follow-up period, there were no episodes of ascending cholangitis, acute pancreatitis, or bleeding. CONCLUSIONS: The new metal stent with an S-shaped anti-reflux valve demonstrated a relatively long duration of stent patency. This was attributable to reductions in duodenobiliary reflux by the anti-reflux valve. Also, the stent with an S-shaped anti-reflux valve is technically feasible and very safe. However, further prospective, randomized comparison studies of stents with anti-reflux valves and conventional stents are needed to evaluate the duration of stent patency.