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©The Author(s) 2022. Published by Baishideng Publishing Group Inc. All rights reserved.
Angle of covered self-expandable metallic stents after placement is a risk factor for recurrent biliary obstruction
Kojiro Tanoue, Hirotsugu Maruyama, Yuki Ishikawa-Kakiya, Yosuke Kinoshita, Kappei Hayashi, Masafumi Yamamura, Masaki Ominami, Yuji Nadatani, Shusei Fukunaga, Koji Otani, Shuhei Hosomi, Fumio Tanaka, Noriko Kamata, Yasuaki Nagami, Koichi Taira, Toshio Watanabe, Yasuhiro Fujiwara
Kojiro Tanoue, Hirotsugu Maruyama, Yuki Ishikawa-Kakiya, Yosuke Kinoshita, Kappei Hayashi, Masafumi Yamamura, Masaki Ominami, Yuji Nadatani, Shusei Fukunaga, Koji Otani, Shuhei Hosomi, Fumio Tanaka, Noriko Kamata, Yasuaki Nagami, Koichi Taira, Toshio Watanabe, Yasuhiro Fujiwara, Department of Gastroenterology, Osaka City University Graduate School of Medicine, Osaka 545-8585, Japan
Author contributions: Tanoue K and Maruyama H contributed to study conception and design; Tanoue K and Maruyama H analyzed and interpreted the data; Tanoue K, Maruyama H, Ishikawa-Kakiya Y, Kinoshita Y, Hayashi K, Yamamura M, Ominami M, Nadatani Y, Fukunaga S, Otani K, Hosomi S, Tanaka F, Kamata N, Nagami Y, Taira K, and Watanabe T wrote, reviewed, and/or revised the manuscript; Fujiwara Y supervised the study; all authors reviewed and approved the final manuscript.
Institutional review board statement: The study was reviewed and approved for publication by our institutional reviewer.
Informed consent statement: All study participants provided written informed consent for personal and medical data collection prior to study enrolment. All patients were given the opportunity to opt out of this study on our website’s homepage.
Conflict-of-interest statement: All authors declare that they have no conflict of interest to disclose.
Data sharing statement: The original anonymous dataset is available upon request from the corresponding author at hiromaruyama99@gmail.com.
Open-Access: This article is an open-access article that was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution NonCommercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See:
https://creativecommons.org/Licenses/by-nc/4.0/ Corresponding author: Hirotsugu Maruyama, MD, PhD, Doctor, Lecturer, Department of Gastroenterology, Osaka City University Graduate School of Medicine, 1-4-3 Asahimachi, Abeno-ku, Osaka 545-8585, Japan. hiromaruyama99@gmail.com
Received: June 8, 2021
Peer-review started: June 8, 2021
First decision: August 18, 2021
Revised: September 1, 2021
Accepted: April 24, 2022
Article in press: April 24, 2022
Published online: May 27, 2022
ARTICLE HIGHLIGHTS
Research background
Covered self-expandable metallic stents (CSEMS) cause recurrent biliary obstruction (RBO), which prevents the continuation of treatment and causes the quality of life in patients with unresectable distal malignant biliary obstruction (MBO) to be poor. To date, sludge formation and food impaction have remained to be major causes of RBO. Recently, CSEMS with a low axial force (AF) to improve compatibility with the bile duct have been used frequently, with increasing concerns that they are likely to cause early RBO as a result of sludge formation and food impaction.
Research motivation
We hypothesized that the time to RBO (TRBO) of CSEMS with a low AF was short. We considered that proving this hypothesis has great significance in the management of patients with CSEMS placement in the clinical practice.
Research objectives
We aimed to evaluate whether the angle of CSEMS after placement is a risk factor for RBO in patients with unresectable distal MBO.
Research methods
Finally, we included 87 patients in this study. We divided the patients into two cohorts, RBO group and non-RBO group, and evaluated the risk factors for RBO including the angle of CSEMS after the placement. Using the SYNAPSE PACS system, we measured the obtuse angle of CSEMS after placement on an abdominal radiograph.
Research results
We found that the angle of CSEMS after placement was an independent risk factor for RBO. Further, we demonstrated that the cut-off value for the angle of CSEMS after placement was 130°, and that time to RBO in the < 130° group was significantly shorter than that in the ≥ 130° group. In our study, among patients who caused RBO of CSEMS in the < 130° angle group, 86% had elevated liver enzymes in the latest laboratory data before the occurrence of RBO, compared with previous laboratory data, and all patients were asymptomatic.
Research conclusions
The findings suggest that the angle of CSEMS after placement for unresectable distal MBO is a risk factor for RBO, and TRBO of CSEMS with a low AF is shorter than that of other CSEMS. Hence, while managing such patients, we suggest the replacement of CSEMS even in asymptomatic patients if the liver enzymes are elevated and the CSEMS angle is < 130°. Additionally, by deploying a new CSEMS with a high AF as needed, it could be possible to expect long-term maintenance without stent dysfunction.
Research perspectives
These results are novel and provide pertinent information for future stent management. However, further prospective studies with larger cohorts are needed to validate our findings.
