Antireflux valve metal stent versus conventional self-expandable metal stent in distal malignant biliary obstruction: a systematic review and meta-analysis

Ann Gastroenterol. 2019 Nov-Dec;32(6):605-613. doi: 10.20524/aog.2019.0427. Epub 2019 Oct 21.


Background: In patients with distal malignant biliary obstruction (MBO), endoscopic biliary drainage using the conventional self-expandable metal stent (SEMS) is the gold standard method for palliative treatment. However, there are limited data on the role of the antireflux valve metal stent (ARVMS). The aim of this study was to compare the safety and efficacy of ARVMS and SEMS in patients with distal MBO.

Methods: We searched PubMed, Ovid, Embase and the Cochrane Library from inception until April 2019 for relevant randomized controlled trials (RCTs). The selected studies provided data regarding technical and clinical success rates, adverse events, and stent dysfunction. Data were meta-analyzed using RevMan software.

Results: Three RCTs were selected, enrolling 293 patients (147 ARVMS and 146 SEMS). The rates of technical success were 95.23% and 99.31% for ARVMS and SEMS groups, respectively (odds ratio [OR] 0.13, 95% confidence interval [CI] 0.01-1.06; P=0.06). The clinical success rates were 91.57% and 89.36% for ARVMS and SEMS groups, respectively (OR 1.30, 95%CI 0.48-3.51; P=0.61). There was no significant difference between the ARVMS and SEMS groups in terms of adverse events (OR 0.61, 95%CI 0.35-1.05; P=0.07) or stent dysfunction (OR 0.77, 95%CI 0.31-1.95; P=0.58), while the incidence of stent occlusion was significantly lower in the ARVMS group (OR 0.44, 95%CI 0.26-0.76; P=0.003).

Conclusion: Our study showed that ARVMS and SEMS had similar technical and clinical success rates. Adverse events were comparable between the 2 arms; however, ARVMS was associated with a lower risk of stent occlusion. Larger RCTs are required to verify the benefit of ARVMS in distal MBO patients.

Keywords: Biliary malignancy; biliary obstruction; meta-analysis; metal stent.