Secondary uncovered versus fully-covered metal stents for the management of occluded stent in unresectable distal malignant biliary obstruction

Introduction: Self-expandable metallic stents (SEMS) have been widely placed for unresectable distal malignant biliary obstruction (UDMBO). However, the dysfunction rate is 19-40% and its treatment is controversial. We aimed asses the efficacy and safety of a secondary biliary stents (uncovered (UC) versus fully-covered (FC) stent) for the management of occluded SEMS.

Patients and methods: Between 2015 and June 2023, 41 patients with UDMBO underwent secondary biliary stent placement as "stent-in-stent" (20 FCSEMS and 21 UCSEMS). The primary outcomes were technical and clinical success of SEMS placement. Secondary outcomes included adverse events (AEs), patency and survival. Patients were prospectively followed until death or loss of follow-up.

Results: Technical (100% vs 85.5%) and clinical (100% vs 95.2%) success rates were similar in FCSEMS and UCSEMS groups. The median follow-up period was 510 days (range 290-630). The median duration of stent patency of FCSEMS (220 days, IQR 137.5-442.5) was longer than UCSEMS (150 days, IQR 110-362.5) (P=0.395), although stent dysfunction within 6 months was not different between groups. Multivariate analysis indicated that sex (HR=0.909, 0.852-0.970), antitumor treatment (HR=0.248, 0.032-0.441), stent patency (HR=0.992, 0.986-0.998) and clinical success (HR=0.133, 0.026-0.690) were significant factors for overall survival. There were no remarkable differences in AEs.

Conclusions: The placement of additional biliary stent using the stent-in-stent method is an effective and safe rescue treatment for patients with UDMBO and occluded stent. In addition, the use of FCSEMS compared UCSEMS has unclear benefits regarding stent patency and overall survival.