Novel biliary self-expanding metal stents: indications and applications

Abstract

Endoscopic insertion of a self-expanding metal stent (SEMS) through a malignant common bile duct stricture is the first line of palliation for malignant jaundice. Patency of these stents remains a major concern. SEMS dysfunction can result from tumor ingrowth, overgrowth and/or clogging. Initial SEMS modifications involved covering the central part of the stent in order to reduce ingrowth and ultimately increase patency. Fully covered stents became available shortly after reports of their use in human patients. The potential removability and radial strength of SEMS have led to evaluation of their use in new indications including benign biliary strictures, post sphincterotomy bleeding and perforation. Other aspects of development include the addition of features such as anti-reflux valves, drug elution and spontaneous biodegradability. These aspects and their clinical implications are reviewed and discussed.

Keywords:

• benign biliary stricture
• biliary leak
• biliary stenosis
• endoscopy
• ERCP
• malignant biliary stricture
• plastic stent
• self-expanding metal stent

Acknowledgements

The authors would like to acknowledge Sandy Field from Sandy Field Scientific for their editorial assistance.

Financial & competing interests disclosure

Dr Jacques Devière has received research support from Cook and Boston Scientific. The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed.

Key issues

• Endoscopic self-expanding metal stents (SEMS) insertion is the first-line approach for palliation of common bile duct malignant strictures. For hilar malignancies, its efficacy is still being compared with the percutaneous approach.

• Fully covered self-expanding metal stent is a promising tool for benign biliary stricture calibration, particularly in cases of chronic pancreatitis.

• Fully covered self-expanding metal stent is also a potential candidate for palliation of distal malignant biliary stricture, particularly in the setting of neoadjuvant therapy or diagnostic uncertainty.

• A wide variety of fully covered self-expanding metal stent have been developed, but the level of evidence supporting their efficacy and safety is still limited for many of them.

• Current drug-eluting stents do not affect neoplastic disease but could be an option for reducing SEMS clogging rates.

• Antireflux features seem to reduce clogging rates without affecting drainage properties.

• Bioabsorbable stents display decreased radial force and disaggregates into the surrounding tissue and should not be used in routine practice.

• The optimal strategies in malignant hilar stricture are still a matter of debate, making comparisons difficult.