Partially covered metal stents have longer patency than uncovered and fully covered metal stents in the management of distal malignant biliary obstruction: a retrospective study

Abstract

BackgroundSelf-expandable metal stents (SEMSs) are widely used for malignant biliary obstructions. Nitinol-covered SEMSs have been developed to improve stent patency. Currently, SEMSs may be uncovered, partially covered, or fully covered; however, there is no consensus on the best stent type for the management of malignant distal biliary obstruction (MDBO).MethodsPatients with unresectable MDBO receiving SEMS (Wallflex™) were retrospectively analyzed. Time to recurrent biliary obstruction (TRBO) and survival time were compared among the three types of SEMSs. Univariate and multivariate analyses were performed to identify risk factors for stent dysfunction.ResultsIn total, 101 patients received SEMSs for unresectable MDBO (44 uncovered, 28 partially covered, and 29 fully covered SEMSs). Median survival time was 200, 168, and 276 days in the uncovered, partially covered, and fully covered SEMSs groups, respectively. There were no differences in survival among the three groups. Median TRBO was 199, 444, and 194 days in the uncovered, partially covered, and fully covered SEMSs groups, respectively. Partially covered SEMSs had longer TRBO than uncovered (p = 0.013) and fully covered (p = 0.010) SEMSs. Tumor ingrowth occurred only with uncovered SEMSs and stent migration occurred only with fully covered SEMSs. Multivariate analyses confirmed that partially covered SEMSs have lower risk of dysfunction.ConclusionsPartially covered SEMSs with a proximal uncovered flared end have longer patency than uncovered and fully covered SEMSs by preventing tumor ingrowth and stent migration.

Self-Expanding Metallic Biliary Stents: Time to Suit Up?

“…The rate of stent migration also did not differ significantly (14 vs. 8%; P = 0.113). The results are similar to a recent retrospective analysis by Yokota et al [7] comparing the clinical outcome of uncovered, partially covered, and fully covered of Wall-Flex™ stents in patients with MBO. Although there was no significant difference in patient survival among the three groups, the rate of RBO was numerically, but not statistically significantly lower with partially covered SEMSs (28.6%) as compared to uncovered (45.4%; P = 0.215) and fully covered (55.2%; P = 0.106) stents.…”

Current Endoscopic Management of Malignant Biliary Stricture

“…Recent studies have revealed that fully covered SEMS (FCSEMS) that are used for MDBO treatment have low stent migration rates and trigger few cholecystitis events [51]. A prospective study of unresectable pancreatic cancer with obstructive jaundice demonstrated a significantly longer survival time and no stent dysfunction for covered SEMS with an anti-migration system than it did without an anti-migration system [52,53]. These studies suggest that covered SEMS are a valuable and cost-effective option for MDBO treatment because of their increased patency, less tumor in-growth, and easy removal [53,54].…”

“…A prospective study of unresectable pancreatic cancer with obstructive jaundice demonstrated a significantly longer survival time and no stent dysfunction for covered SEMS with an anti-migration system than it did without an anti-migration system [52,53]. These studies suggest that covered SEMS are a valuable and cost-effective option for MDBO treatment because of their increased patency, less tumor in-growth, and easy removal [53,54]. However, several recent large studies [55][56][57] and a recent meta-analysis from Canada [58] have revealed no clear benefit of FCSEMS over uncovered SEMS (UCSEMS) in terms of stent patency and complications.…”

Biomaterials in Gastroenterology: A Critical Overview

“…While SEMSs pushed the service life of the stents to 6 months or longer, they also have drawbacks, for instance getting embedded into the duct walls. Covering the metal wire with polymers solved this issue, but increased the risk of stent migration, albeit the covered SEMSs may offer generally a lower risk of dysfunction [165] in spite of previous different opinions [166].…”