Observational Study
Copyright ©The Author(s) 2023. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastroenterol. Jul 21, 2023; 29(27): 4344-4355
Published online Jul 21, 2023. doi: 10.3748/wjg.v29.i27.4344
Predicting portal venous anomalies by left-sided gallbladder or right-sided ligamentum teres hepatis: A large scale, propensity score-matched study
Hsuan-Yin Lin, Rheun-Chuan Lee, Jyh-Wen Chai, Chiann-Yi Hsu, Yen Chou, Hsuen-En Hwang, Chien An Liu, Nai-Chi Chiu, Ho-Hsian Yen
Hsuan-Yin Lin, Jyh-Wen Chai, Department of Radiology, Taichung Veterans General Hospital, Taichung 407219, Taiwan
Rheun-Chuan Lee, Hsuen-En Hwang, Chien An Liu, Nai-Chi Chiu, Department of Radiology, Taipei Veterans General Hospital, Taipei 11267, Taiwan
Rheun-Chuan Lee, Hsuen-En Hwang, Chien An Liu, Nai-Chi Chiu, School of Medicine, National Yang Ming Chiao Tung University, Taipei 112, Taiwan
Chiann-Yi Hsu, Department of Medical Research, Taichung Veterans General Hospital, Taichung 40705, Taiwan
Yen Chou, Department of Radiology, Fu Jen Catholic University Hospital, Taipei 24352, Taiwan
Ho-Hsian Yen, Department of Radiology, Far Eastern Memorial Hospital, New Taipei City 220, Taiwan
Author contributions: Lin HY and Lee RC contributed to the conception and design; all authors contributed to the administrative support; Lin HY, Lee RC and Chai JW contributed to the provision of study materials or patients; all authors contributed to the collection and assembly of data; Lin HY and Hsu CY contributed to the data analysis and interpretation; Lin HY contributed to the manuscript writing and final approval of manuscript.
Institutional review board statement: The study was reviewed and approved by the Institutional Review Board I&II of Taichung Veterans General Hospital (Approval No. TCVGH-IRB No. CE22408B).
Informed consent statement: Patients were not required to give informed consent to the study because the analysis used anonymous clinical data that were obtained after each patient agreed to treatment by written consent.
Conflict-of-interest statement: The authors of this manuscript declare no relationships with any companies, whose products or services may be related to the subject matter of the article.
Data sharing statement: No additional data are available.
STROBE statement: The authors have read the STROBE Statement—checklist of items, and the manuscript was prepared and revised according to the STROBE Statement—checklist of items.
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: Hsuan-Yin Lin, MD, Attending Doctor, Department of Radiology, Taichung Veterans General Hospital, No. 1650 Taiwan Boulevard Section 4, Taichung 407219, Taiwan. b101096132@tmu.edu.tw
Received: March 29, 2023
Peer-review started: March 29, 2023
First decision: May 23, 2023
Revised: June 6, 2023
Accepted: July 6, 2023
Article in press: July 6, 2023
Published online: July 21, 2023
ARTICLE HIGHLIGHTS
Research background

The presence of right-sided ligamentum teres (RSLT) is often accompanied by portal venous anomalies (PVAs) and is considered a worrisome characteristic in hepatobiliary interventions. Most studies hypothesis that left-sided gallbladder (LGB) must exist with RSLT. However, in a reported study, right-sided gallbladder (RGB) was observed in livers with RSLT. Therefore, the relationship between the ligamentum teres hepatis (LT), gallbladder (GB), and PVAs is controversial and requires further investigation, despite the rarity of the anatomical variation of LT and GB, which can complicate statistical analysis.

Research motivation

To verify whether the RSLT coexists with a typical RGB, represent genuine existing variations or were merely misinterpreted and to determine the key predictors of major PVA, we conducted a comprehensive investigation. Additionally, to the best of our knowledge, all previous articles focusing on the RSLT had small sample sizes, not exceeding 1000.

Research objectives

First, to draw attention to the uncommon occurrence of the RSLT without the presence of the gallbladder (LGB), and secondly, to assess the reliability of both the LT and gallbladder location in predicting PVAs.

Research methods

This retrospective study examined a total of 8552 contrast-enhanced abdominal computed tomography examinations conducted between 2018 and 2021, involving 4483 men and 4069 women, with a mean age of 59.5 ± 16.2 (SD) years. The primary focus was to assess major PVAs as a surrogate outcome. The cases were categorized into four subgroups based on the locations of the gallbladder and LT. On one hand, we analyzed the prevalence of PVAs based on LT locations while controlling for gallbladder location (n = 36). On the other hand, we controlled for LT location and determined the prevalence of PVAs based on gallbladder locations (n = 34). Lastly, we investigated the independent influence of LT location on PVA using propensity score matching (PSM) and inverse probability of treatment weighting (IPTW).

Research results

We identified a total of 9 cases where the RSLT coexisted with a typical RGB location. Among the cases with a LGB, the presence of RSLT was associated with a significantly higher prevalence of PVAs compared to those with a typical LT [80.0% vs 18.2%, P = 0.001; odds ratio (OR) = 18, 95% confidence interval (CI): 2.92-110.96]. However, when RSLT was present, there was no statistically significant difference in PVA prevalence between RGB and LGB cases (88.9% vs 80.0%, P > 0.99). We employed PSM and IPTW to ensure balanced cohorts in terms of demographics and gallbladder locations. After adjusting for these factors using PSM, the RSLT group still exhibited a significantly higher PVAs prevalence compared to the LT group (77.3% vs 4.5%, P < 0.001; OR = 16.27, 95%CI: 2.25-117.53). Similar results were observed when utilizing IPTW (82.5% vs 4.7%, P < 0.001).

Research conclusions

RSLT doesn't always coexist with LGB. RSLT can predict PVA independently while the gallbladder location does not serve as a sufficient predictor.

Research perspectives

Further investigation is needed to determine whether the existence of RSLT can predict the most predominant type of biliary or arterial anatomical variation.