Retrospective Study
Copyright ©The Author(s) 2022. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Hepatol. May 27, 2022; 14(5): 992-1005
Published online May 27, 2022. doi: 10.4254/wjh.v14.i5.992
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
Processing time: 349 Days and 21 Hours
Abstract
BACKGROUND

Studies have shown that covered self-expandable metallic stents (CSEMS) with a low axial forces after placement can cause early recurrent biliary obstruction (RBO) due to precipitating sludge formation.

AIM

To ascertain whether the angle of CSEMS after placement is a risk factor for RBO in unresectable distal malignant biliary obstruction (MBO).

METHODS

Between January 2010 and March 2019, 261 consecutive patients underwent self-expandable metallic stent insertion by endoscopic retrograde cholangiopancreatography at our facility, and 87 patients were included in this study. We evaluated the risk factors for RBO, including the angle of CSEMS after placement as the primary outcome. We measured the obtuse angle of CSEMS after placement on an abdominal radiograph using the SYNAPSE PACS system. We also evaluated technical and functional success, adverse events, time to RBO (TRBO), non-RBO rate, survival time, cause of RBO, and reintervention procedure as secondary outcomes.

RESULTS

We divided the patients into two cohorts based on the presence or absence of RBO. The angle of CSEMS after placement (per 1° and per 10°) was evaluated using the multivariate Cox proportional hazard analysis, which was an independent risk factor for RBO in unresectable distal MBO [hazard ratio, 0.97 and 0.71; 95% confidence interval (CI): 0.94-0.99 and 0.54-0.92; P = 0.01 and 0.01, respectively]. For early diagnosis of RBO, the cut-off value of the angle of CSEMS after placement using the receiver operating characteristic curve was 130° [sensitivity, 50.0%; specificity 85.5%; area under the curve 0.70 (95%CI: 0.57-0.84)]. TRBO in the < 130° angle group was significantly shorter than that in the ≥ 130° angle group (P < 0.01).

CONCLUSION

This study suggests that the angle of the CSEMS after placement for unresectable distal MBO is a risk factor for RBO. These novel results provide pertinent information for future stent management.

Keywords: Covered self-expandable metallic stents; Recurrent biliary obstruction; Malignant biliary obstruction; Endoscopic retrograde cholangiopancreatography; Angle; Axial force

Core Tip: We aimed to assess whether the angle of covered self-expandable metallic stents (CSEMS) after placement is a risk factor for recurrent biliary obstruction (RBO) in patients with unresectable distal malignant biliary obstruction. We included 87 patients in this study and divided them into two cohorts. We found that the angle of the CSEMS after placement was an independent risk factor for RBO. Furthermore, we demonstrated that the cut-off value of 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.