Clin Endosc.  2024 May;57(3):375-383. 10.5946/ce.2023.035.

A novel fully covered metal stent for unresectable malignant distal biliary obstruction: results of a multicenter prospective study

• Sakai A
• Masuda A
• Eguchi T
• Furumatsu K
• Iemoto T
• Yoshida S
• Okabe Y
• Yamanaka K
• Miki I
• Kakuyama S
• Yagi Y
• Shirasaka D
• Kohashi S
• Kobayashi T
• Shiomi H
• Kodama Y

• KMID: 2555899
• DOI: http://doi.org/10.5946/ce.2023.035

Abstract

Background/Aims
Endoscopic self-expandable metal stent (SEMS) placement is currently the standard technique for treating unresectable malignant distal biliary obstructions (MDBO). Therefore, covered SEMS with longer stent patency and fewer migrations are required. This study aimed to assess the clinical performance of a novel, fully covered SEMS for unresectable MDBO.
Methods
This was a multicenter single-arm prospective study. The primary outcome was a non-obstruction rate at 6 months. The secondary outcomes were overall survival (OS), recurrent biliary obstruction (RBO), time to RBO (TRBO), technical and clinical success, and adverse events.
Results
A total of 73 patients were enrolled in this study. The non-obstruction rate at 6 months was 61%. The median OS and TRBO were 233 and 216 days, respectively. The technical and clinical success rates were 100% and 97%, respectively. Furthermore, the rate of occurrence of RBO and adverse events was 49% and 21%, respectively. The length of bile duct stenosis (<2.2 cm) was the only significant risk factor for stent migration.
Conclusions
The non-obstruction rate of a novel fully covered SEMS for MDBO is comparable to that reported earlier but shorter than expected. Short bile duct stenosis is a significant risk factor for stent migration.

Keyword

Covered self-expandable metal stent; Malignant distal biliary obstruction; Stent migration

Figure

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  Fig. 1. (A) The fully covered self-expandable metal stent (SEMS) used in this study was constructed using a single woven nitinol wire with a silicone-covered membrane. The stent had flanged ends to mitigate migration. (B) The stent was deployed using a controlled-release, trigger-driven delivery system. This system allowed recapturing of the SEMS before complete deployment if repositioning was required.

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  Fig. 2. (A) The Kaplan–Meier curve shows the patient survival. The median overall survival was 233 days. (B) The Kaplan–Meier curve shows the time to recurrent biliary obstruction (TRBO). The median TRBO was 216 days. The non-obstruction rate at 6 months was 61%.

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  Fig. 3. The Kaplan–Meier curve shows the time to recurrent biliary obstruction (TRBO) of the patients with a length of bile duct stenosis of 2.2 cm or more (A) and others (B). The median TRBO was 276 days (A) and 158 days (B). Although not statistically significant, patients with a length of bile duct stenosis of 2.2 cm or more tended to have a longer TRBO than others (p=0.068).

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