Anchoring of fully covered self-expandable metal stents: selected patients or all?

We recently read with interest the article by Paik et al. reporting a randomized controlled study that demonstrated that an additional double-pigtail plastic stent anchoring a fully covered self-expandable metal stent (FCSEMS) for malignant biliary obstruction prevented stent migration and prolonged patency without any serious adverse events [1]. International consensus recommends the use of covered metal stents for unresectable malignant distal biliary stricture [2], with stent migration being one of the most concerning adverse events with FCSEMSs [3]. Before applying double-pigtail stent anchoring of FCSEMSs in general practice, there are several points that need to be clarified.

First, the shorter length of the FCSEMSs used in this study may have resulted in a higher migration rate in the non-anchored group, this having been even higher than that for FCSEMSs used in benign lesions, around 5 %–37 % [1] [4]. Kogure et al. revealed that the stent migration rate in FCSEMSs used for malignant distal biliary obstruction was only 14 % with stent lengths of mostly 6 or 8 cm [3]. Furthermore, plastic stent anchoring of FCSEMSs has also been reported to carry a higher risk of sludge formation in the plastic stent [5]. Is the benefit of the antimigration effect from using an anchoring plastic stent really greater than the reduced stent patency rate?

Second, the patient factors associated with migration do not seem to have been well described and analyzed. The timing of FCSEMS insertion, severity of biliary stenosis, length of stenosis, angulation of the common bile duct, and tumor response to chemotherapy would all be important factors associated with the stent migration rate. Third, the relative position of the FCSEMS and critically the obstructive level are also of concern. The waist of the FCSEMS and the relative length of the FCSEMS to the stenosis are possible factors related to stent migration.

We appreciate the concept of plastic stents anchoring FCSEMSs as in this study. However, we consider the use of plastic stents to anchor FCSEMSs should be considered for selected patients, but not all.

Publication History

Article published online:
24 November 2021

• References

• 1 Paik WH, Woo SM, Chun JW. et al. Efficacy of an internal anchoring plastic stent to prevent migration of a fully covered metal stent in malignant distal biliary strictures: a randomized controlled study. Endoscopy 2021; 53: 578-585
• 2 Nakai Y, Isayama H, Wang HP. et al. International consensus statements for endoscopic management of distal biliary stricture. J Gastroenterol Hepatol 2020; 35: 967-979
• 3 Kogure H, Ryozawa S, Maetani I. et al. A prospective multicenter study of a fully covered metal stent in patients with distal malignant biliary obstruction: WATCH-2 study. Dig Dis Sci 2018; 63: 2466-2473
• 4 Dumonceau JM, Tringali A, Blero D. et al. Biliary stenting: indications, choice of stents and results: European Society of Gastrointestinal Endoscopy (ESGE) clinical guideline. Endoscopy 2012; 44: 277-298
• 5 Li J, Li T, Sun P. et al. Covered versus uncovered self-expandable metal stents for managing malignant distal biliary obstruction: a meta-analysis. PLoS One 2016; 11: e0149066