Antireflux metal stent for biliary obstruction: Any benefits?

Abstract

Endoscopic retrograde cholangiopancreatography with stent placement has been utilized as standard palliative management of distal malignant biliary obstruction (MBO). Compared to plastic stents, metal stents can provide longer‐term relief of symptoms. When a large‐bore metal stent is placed across the ampulla, patients are predisposed to the risk of cholangitis or stent dysfunction due to reflux of duodenal contents. To mitigate the risk of adverse events associated with the duodenobiliary reflux, efforts have been directed to development of antireflux metal stents (ARMSs). The antireflux property has been introduced through adding of an antireflux valve to the duodenal stent end. Evidence from clinical studies indicates that ARMSs may not only reduce the risk of ascending cholangitis during follow‐up but also prolong stent patency time. However, the results of clinical studies testing ARMSs are inconsistent owing to heterogeneous designs of antireflux valves and stent bodies. Metal stents are increasingly indicated for benign biliary strictures and MBO in the setting of neoadjuvant chemotherapy, and therefore, research is warranted to evaluate ARMSs for those indications. Given that endoscopic ultrasound (EUS)‐guided transmural biliary drainage has gained popularity, the optimal timing of placing an ARMS in relation to EUS‐guided and percutaneous drainage should be investigated. Development and evaluation of ARMSs require an integrative approach utilizing phantom and animal models, measurements of stent mechanical properties, and in vivo functional study after stent placement. In this review article, we summarize updated evidence on ARMSs for MBO and discuss issues that should be addressed in future studies.

Feasibility of biliary stenting to distal malignant biliary obstruction using a novel designed metal stent with duckbill‐shaped anti‐reflux valve

“…23 Therefore, further improvement is required to develop the most appropriate ARMS. 24 In the present study, the technical success rate and functional success rate of biliary stenting using D-ARMS were 93% and 87%, respectively. These values are comparable to previous reports, suggesting that D-ARMS is feasible for biliary stenting.…”

“…Their study demonstrated that a duodenal pH environment induced a morphological change of ARV leading to stent dysfunction 23 . Therefore, further improvement is required to develop the most appropriate ARMS 24 …”

A Prospective Multicenter Study of “Inside Stents” for Biliary Stricture: Multicenter Evolving Inside Stent Registry (MEISteR)

“…There are two treatment options to prevent duodenobiliary reflux itself; anti-reflux stents and stent above the papilla. Clinical trials of anti-reflux biliary stents have been conducted, but their role is still controversial [8]. Stents above the papilla, so-called "inside stents," have been investigated using both metal and plastic stents [9].…”

Endoscopic treatment of benign biliary stricture using different stents: a systematic review and meta-analysis.

“…FCSEMSs are usually designed with a larger diameter to a have longer patency period. However, this design also results in a reflux of duodenal contents, leading to cholangitis and sludge occlusion [42]. For MPSs, cholangitis resulting from frequent interventions was the most common adverse event.…”