Zhang WQ, Li KJ, Yang F, Jiang GJ, Zhang L, Jiang H, Guo H, Li SW. Association of smaller-diameter underdilation of transjugular intrahepatic portosystemic shunt stents with improved long-term survival: A propensity score-matched study. World J Gastroenterol 2026; 32(45): 121243 [DOI: 10.3748/wjg.121243]
Corresponding Author of This Article
Song-Wei Li, MD, Associate Professor, Department of Interventional Radiology, The Second Affiliated Hospital of Kunming Medical University, No. 374 Dianmian Avenue, Wuhua District, Kunming 650101, Yunnan Province, China. lisongwei@kmmu.edu.cn
Research Domain of This Article
Gastroenterology & Hepatology
Article-Type of This Article
research-article
Open-Access Policy of This Article
This article is an open-access article which was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution Non Commercial (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: http://creativecommons.org/licenses/by-nc/4.0/
Baishideng Publishing Group Inc, 7041 Koll Center Parkway, Suite 160, Pleasanton, CA 94566, USA
Share the Article
Zhang WQ, Li KJ, Yang F, Jiang GJ, Zhang L, Jiang H, Guo H, Li SW. Association of smaller-diameter underdilation of transjugular intrahepatic portosystemic shunt stents with improved long-term survival: A propensity score-matched study. World J Gastroenterol 2026; 32(45): 121243 [DOI: 10.3748/wjg.121243]
World J Gastroenterol. Dec 7, 2026; 32(45): 121243 Published online Dec 7, 2026. doi: 10.3748/wjg.121243
Association of smaller-diameter underdilation of transjugular intrahepatic portosystemic shunt stents with improved long-term survival: A propensity score-matched study
Wen-Qing Zhang, Fan Yang, Lei Zhang, Hua Jiang, Song-Wei Li, Department of Interventional Radiology, The Second Affiliated Hospital of Kunming Medical University, Kunming 650101, Yunnan Province, China
Ke-Jia Li, Department of Pharmacy, The Second Affiliated Hospital of Kunming Medical University, Kunming 650101, Yunnan Province, China
Guang-Jin Jiang, Department of Radiology, The Second People’s Hospital of Baoshan, Baoshan 678000, Yunnan Province, China
Hao Guo, Department of Radiology, The People’s Hospital of Simao District (Pu’er Central Hospital), Pu’er 665000, Yunnan Province, China
Author contributions: Zhang WQ performed the statistical analysis and wrote the original manuscript; Li KJ participated in the study design, provided postoperative medication guidance, revised the manuscript according to reviewers’ comments, and obtained the funding support; Yang F, Jiang GJ, Zhang L, and Guo H collected the data and conducted follow-up; Jiang H editing the figure; Li SW designed the study, supervised the research, performed the statistical analysis, reviewed the manuscript, and obtained the funding support. Zhang WQ and Li KJ contributed equally to the work as co-first authors. All authors have read and approve the final manuscript.
AI contribution statement: AI tools (specifically DeepSeek, Gemini, ChatGPT) were used solely for language polishing and code assistance. No AI tool was involved in the generation of research data, interpretation of results, or formulation of conclusions. All AI-generated outputs were critically reviewed and revised by the authors.
Supported by Scientific Research Fund of Yunnan Provincial Department of Education, No. 2024J0233; and Yunnan Fundamental Research Kunming Medical University Joint Projects, No. 202501AY070001-085.
Institutional review board statement: The study was reviewed and approved by the Ethics Committee of the Second Affiliated Hospital of Kunming Medical University (Approval No. PJ-KY-2026-12).
Informed consent statement: According to the Declaration of Helsinki, informed consent requirements were waived due to the retrospective nature of the study design.
Conflict-of-interest statement: All the authors report no relevant conflicts of interest for this article.
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.
Data sharing statement: No additional data are available.
Corresponding author: Song-Wei Li, MD, Associate Professor, Department of Interventional Radiology, The Second Affiliated Hospital of Kunming Medical University, No. 374 Dianmian Avenue, Wuhua District, Kunming 650101, Yunnan Province, China. lisongwei@kmmu.edu.cn
Received: March 27, 2026 Revised: May 19, 2026 Accepted: June 29, 2026 Published online: December 7, 2026 Processing time: 202 Days and 14.7 Hours
Abstract
BACKGROUND
In clinical practice, the choices of stent diameter and dilation strategy during the transjugular intrahepatic portosystemic shunt (TIPS) procedure are critical factors that influence patient outcomes, necessitating a balance between adequate portal decompression and preventing complications. Therefore, optimizing stent implantation strategies is urgently needed to enhance patient outcomes.
AIM
To evaluate the impact of underdilating an 8-mm expanded polytetrafluoroethylene (ePTFE)-covered stent to ≤ 6 mm vs ≥ 7 mm during the TIPS procedure on postoperative overt hepatic encephalopathy (OHE), rebleeding, stent dysfunction, and survival.
METHODS
This retrospective cohort study included 192 patients who underwent TIPS with an 8-mm ePTFE-covered stent in a tertiary hospital between August 1, 2016, and December 31, 2020. Patients were divided into two groups based on underdilation diameter (≤ 6 mm vs ≥ 7 mm); subsequent 1:1 propensity score matching (PSM) yielded 78 patients per group. The primary endpoints were overall survival (OS) and OHE incidence, and the secondary endpoints included variceal rebleeding and shunt dysfunction. Kaplan-Meier survival analysis, the log-rank test, and multivariable Cox regression analysis were used to assess the effect of stent underdilation on post-TIPS survival.
RESULTS
Among the 192 patients, 49 developed OHE within 1 year after TIPS. During follow-up, 48 patients died, 24 experienced rebleeding, and 15 developed shunt dysfunction. Before PSM, the incidences of OHE in the ≤ 6 mm and ≥ 7 mm groups were 24.4% and 26.5%, respectively (P = 0.748); after PSM, these incidences were 21.8% and 28.2% (P = 0.355). Mortality rates were lower in the ≤ 6 mm group than in the ≥ 7 mm group both before (16.7% vs 32.4%, P = 0.012) and after matching (14.1% vs 34.6%, P = 0.003). No significant differences were observed between the groups regarding rebleeding rates (before PSM: 14.4% vs 10.8%, P = 0.444; after PSM: 14.1% vs 11.5%, P = 0.632) or shunt dysfunction rates (before PSM: 5.6% vs 9.8%, P = 0.274; after PSM: 5.1% vs 11.5%, P = 0.148). Ordinal logistic regression demonstrated no significant association between the underdilation strategy and OHE severity (odds ratio = 0.683, 95% confidence interval: 0.194-2.404, P = 0.552). Kaplan-Meier analysis after PSM showed improved OS in the ≤ 6 mm group (log-rank P = 0.015). Multivariable Cox regression identified underdilation to ≤ 6 mm as an independent protective factor for OS (hazard ratio = 0.422, 95% confidence interval: 0.203-0.877, P = 0.021).
CONCLUSION
Underdilating an 8-mm ePTFE-covered stent during the TIPS procedure does not affect postoperative rebleeding or shunt dysfunction. Compared with underdilation to ≥ 7 mm, underdilation to ≤ 6 mm does not decrease the incidence of postoperative OHE but reduces mortality risk, conferring a substantial survival benefit.
Core Tip: In our study, underdilating an 8-mm expanded polytetrafluoroethylene-covered stent to ≤ 6 mm vs ≥ 7 mm during transjugular intrahepatic portosystemic shunt showed no significant differences regarding the incidences of postoperative rebleeding, shunt dysfunction, and overt hepatic encephalopathy; however, it substantially reduced the mortality risk in the ≤ 6 mm group. Underdilating the stent to ≤ 6 mm appears to recalibrate the risk-benefit balance during transjugular intrahepatic portosystemic shunt with 8-mm expanded polytetrafluoroethylene-covered stents, yielding superior mid-to-long-term survival benefits.
Citation: Zhang WQ, Li KJ, Yang F, Jiang GJ, Zhang L, Jiang H, Guo H, Li SW. Association of smaller-diameter underdilation of transjugular intrahepatic portosystemic shunt stents with improved long-term survival: A propensity score-matched study. World J Gastroenterol 2026; 32(45): 121243
Liver cirrhosis is the eleventh leading cause of death worldwide, resulting in over one million fatalities each year[1]. As cirrhosis advances to a decompensated stage, it progressively leads to portal hypertension (PH), one of its most severe complications. PH can cause life-threatening complications, including esophagogastric variceal bleeding, refractory ascites, and hepatic hydrothorax, with the six-week mortality rate for acute variceal bleeding reaching 20%[2]. These complications pose a substantial threat to patient survival. The transjugular intrahepatic portosystemic shunt (TIPS) procedure creates a shunt between the hepatic and portal veins using minimally invasive techniques, markedly decreasing portal resistance. Compared with other treatments, TIPS not only alleviates clinical symptoms but also substantially lowers mortality rates in patients with decompensated cirrhosis[3,4].
Recently, the extensive use of expanded polytetrafluoroethylene (ePTFE)-covered stents in the TIPS procedure has substantially reduced shunt stenosis rates (bare stents: 50%-70% vs covered stents: 10%-20%), thereby considerably improving patient prognoses[5]. Consequently, guidelines recommend ePTFE-covered stents as the standard option for TIPS creation[6-8]. However, insufficient individualized shunt strategies and post-TIPS complications, such as hepatic encephalopathy (HE) and shunt dysfunction, persist as substantial challenges. In clinical practice, the selections of stent diameter and dilation strategy during TIPS are critical factors that influence patient outcomes, necessitating a balance between adequate portal decompression and preventing complications. An appropriate shunt diameter is essential for lowering portal pressure and preventing rebleeding; however, an excessively large diameter may result in over-shunting, which can lead to HE and inadequate liver perfusion[9,10]. The occurrence of HE following TIPS remains a major concern, particularly given the high postoperative mortality rate (60%) among patients with end-stage liver cirrhosis[11]. These factors underscore the urgent need to optimize stent implantation strategies to improve patient outcomes.
Selecting the stent diameter during TIPS placement, specifically to precisely regulate shunt flow, represents a fundamental challenge in balancing efficacy and safety. Larger-diameter stents (e.g., 10 mm) facilitate effective portal decompression but are associated with an increased risk of overt HE (OHE). Conversely, smaller-diameter stents (e.g., 6-8 mm) decrease the incidence of postoperative OHE but may result in PH recurrence due to inadequate shunting[12-14]. Underdilation strategies, which involve the controlled expansion of stents using balloons smaller than the stent’s diameter (e.g., expanding an 8-mm stent with a 5-, 6-, or 7-mm balloon), have emerged as innovative techniques aimed at achieving “appropriate shunting”. Theoretically, this approach reduces the incidence of postprocedural OHE and mitigates ischemic liver damage by facilitating “moderate shunting”, thereby lowering the portal pressure gradient (PPG) and improving prognosis[15]. However, clinical evidence supporting these strategies remains limited, primarily consisting of retrospective single-center studies with small sample sizes[16]. These studies lack high-quality evidence linking stent underdilation strategies to postoperative OHE incidences and survival rates.
This study aims to address the challenges of balancing efficacy (lowering portal pressure) and safety (minimizing OHE risk) in traditional TIPS procedures. We hypothesize that employing smaller-diameter (≤ 6 mm) balloon underdilation strategies may lead to improved clinical outcomes - specifically by reducing postoperative OHE incidence and improving overall survival (OS) rates - without substantially increasing variceal rebleeding or shunt dysfunction risks. To test this hypothesis, we conducted a retrospective cohort study of patients who underwent TIPS using 8-mm ePTFE-covered stents, applying 1:1 propensity score matching (PSM) to enhance group comparability. The primary endpoints were all-cause mortality rate and OHE incidence, and the secondary endpoints included variceal rebleeding and shunt dysfunction.
MATERIALS AND METHODS
Study design and patient selection
We conducted a retrospective analysis of the demographic and baseline clinical characteristics of 275 patients with liver cirrhosis and PH who underwent the TIPS procedure at the Second Affiliated Hospital of Kunming Medical University between August 1, 2016, and December 31, 2020. The last follow-up date was December 31, 2023. After excluding patients who received non-Viatorr stents (n = 18), underwent parallel TIPS procedures (n = 1), had unsuccessful surgeries (n = 2), or had incomplete or missing follow-up data (n = 62), a total of 192 patients were ultimately included in the study (Figure 1). Institutional review board approval was obtained from the Ethics Committee of the Second Affiliated Hospital of Kunming Medical University (Approval No. PJ-KY-2026-12). In accordance with the Declaration of Helsinki, informed consent requirements were waived due to the retrospective nature of the study.
Figure 1 Flow chart of patient selection.
A total of 275 patients with liver cirrhosis and portal hypertension underwent transjugular intrahepatic portosystemic shunt procedures. After excluding patients who received non-Viatorr covered stents (n = 18), underwent parallel transjugular intrahepatic portosystemic shunt procedures (n = 1), had unsuccessful surgeries (n = 2), or had incomplete or missing follow-up data (n = 62), 192 patients were ultimately included in the study. TIPS: Transjugular intrahepatic portosystemic shunt; PSM: Propensity score matching.
PSM
Patients were divided into ≤ 6 mm and ≥ 7 mm groups based on the balloon diameter used to underdilate the 8-mm ePTFE-covered stent during TIPS: 90 patients in the ≤ 6 mm group and 102 patients in the ≥ 7 mm group. PSM using the nearest neighbor matching algorithm in IBM SPSS Statistics 25.0 (SPSS Inc., Armonk, NY, United States) was performed with a caliper of 0.2 to adjust for age, sex, body mass index, type of cirrhosis, Child-Pugh (CTP) classification, and indication, yielding a well-balanced cohort of 78 matched patient pairs (Table 1).
Table 1 Patient characteristics before and after propensity score matching, n (%)/mean ± SD.
Clinical assessments and the TIPS procedure were performed by two experienced interventional radiologists. After successful puncture of the right internal jugular vein under local anesthesia, the TIPS set (RUPS-100; Cook, Bloomington, IN, United States) was inserted into the hepatic vein to puncture and access the portal vein. Subsequently, the RUPS-100 outer sheath was guided into the main portal vein over a stiff guidewire. The pre-procedural PPG was measured using a pressure sensor system. All patients underwent portal vein angiography to identify esophageal and gastric varices, which were subsequently embolized with metal coils (MReye; Cook Inc., Bloomington, IN, United States). An 8-mm ePTFE-covered stent (Viatorr; W.L. Gore & Associates, Flagstaff, AZ, United States) was subsequently placed across the hepatic puncture tract, followed by partially dilating the hepatic parenchymal segment of the stent using either ≤ 6 mm or ≥ 7 mm balloon catheters (Advance; Cook, Bloomington, IN, United States). Postoperatively, angiography and PPG measurements were performed. The selection of the shunt balloon diameter was initially influenced by early clinical cases favoring ≥ 7 mm dilation; however, subsequent procedures accounted for clinical practice and the specific needs of Asian populations, leading to a preference for ≤ 6 mm.
Follow-up and outcome
Post-TIPS management followed the Chinese clinical guidelines in conjunction with actual clinical practice. For primary prophylaxis against HE, lactulose (15 mL orally three times daily) was administered. Because rifaximin was unavailable in our region during the study period, no patients received it. Diuretics were not routinely used for primary prophylaxis against ascites recurrence but were adjusted individually based on the patient’s ascites status and renal function during postoperative follow-up. All patients were followed up at 1 week, 1 month, 6 months, and 1 year postoperatively, with annual assessments thereafter. Follow-up was primarily conducted through telephone calls, outpatient clinic visits, or inpatient medical record reviews, resulting in an average follow-up duration of 52 months. The primary outcomes assessed were postoperative OHE incidence and all-cause mortality, and the secondary endpoints included postoperative rebleeding incidence and shunt dysfunction. OS was defined as the time interval from the TIPS procedure until death from any cause during the follow-up period. OHE was defined as grade II or higher based on the West Haven criteria[17]. Postoperative rebleeding was defined as recurrent melena, hematemesis, or other signs of gastrointestinal bleeding after TIPS, subsequently confirmed by endoscopy as variceal hemorrhage. Shunt dysfunction was diagnosed if contrast-enhanced computed tomography (CT) of the portal vein or ultrasound revealed stent stenosis or occlusion.
Statistical analysis
Statistical analysis was performed using IBM SPSS 25.0 software and R version 4.2.1; all tests were two-tailed, and P < 0.05 was considered statistically significant. The normality of the data distribution was assessed. Quantitative data were expressed as means ± SDs for normally distributed continuous variables, or medians (interquartile ranges) for non-normally distributed variables; intergroup comparisons were performed using independent-samples t-tests or Mann-Whitney U tests, respectively. Categorical data were expressed as n (%) and compared using the χ2 test. To adjust for intergroup confounding factors and enhance balance, 1:1 PSM was performed using a nearest-neighbor algorithm. The underdilation diameter (≤ 6 mm vs ≥ 7 mm) served as the grouping variable, and covariates included age, sex, body mass index, cirrhosis type, CTP classification, and indication, with a caliper of 0.2. Post-matching results showed that all standardized mean differences were below 0.1, indicating successful covariate balance. Kaplan-Meier curves for OS were plotted for both groups pre- and post-matching, and intergroup differences were assessed using the log-rank test. To further ascertain the effect of the underdilation strategy on postoperative OS, univariate and multivariable Cox regression analyses were conducted on the matched cohort.
RESULTS
Patient characteristics
Of the 275 patients screened based on the inclusion and exclusion criteria, 192 were ultimately included in this study. Table 1 presents the baseline characteristics of the patients both pre- and post-PSM. Prior to PSM, there were 90 patients in the ≤ 6 mm underdilation group and 102 patients in the ≥ 7 mm group. The groups showed significant differences in age, gender, TIPS indication, presence of tumors, and hypertension (P < 0.05). Post-PSM, both groups consisted of 78 patients, achieving balance across all observed variables, with no significant intergroup differences (P > 0.05). The post-PSM standardized mean differences for all variables were less than 0.1, indicating effective matching (Figure 2).
Figure 2 Comparison of standardized mean differences in the main baseline characteristics of transjugular intrahepatic portosystemic shunt patients before and after propensity score matching.
Before propensity score matching, there were statistically significant differences between the two groups regarding liver cancer, indication for transjugular intrahepatic portosystemic shunt, hypertension, sex, and age; the standardized mean differences for all variables were > 0.2. After propensity score matching, the standardized mean differences for all variables were < 0.1, indicating effective matching. PSM: Propensity score matching.
Outcomes
Rebleeding and shunt dysfunction: Before PSM, the incidences of postprocedural rebleeding in the ≤ 6 mm and ≥ 7 mm groups were 14.4% and 10.8%, respectively (P = 0.444); after PSM, these incidences were 14.1% and 11.5%, respectively (P = 0.632). Similarly, the incidences of postoperative shunt dysfunction in the ≤ 6 mm and ≥ 7 mm groups were 5.6% and 9.8% before PSM (P = 0.274), and 5.1% and 11.9% after PSM (P = 0.148), demonstrating no significant intergroup differences.
OHE: Among the 192 patients pre-PSM, 49 (25.5%) developed OHE within 1 year post-procedure; post-PSM, 39 of 156 patients (25.0%) developed OHE within the same timeframe. The 1-year postoperative OHE incidences in the ≤ 6 mm and ≥ 7 mm groups were 24.4% and 26.5% pre-PSM (P = 0.748), and 21.8% and 28.2% post-PSM (P = 0.355). To further assess the impact of the underdilation strategy on postoperative HE severity, patients were categorized using the West Haven criteria: Among the 49 patients with OHE, 8 had grad 1, 10 had grade 2, 20 had grade 3, and 11 had grade 4. Ordinal multivariable logistic regression, adjusted for potential covariates, revealed no significant association between the underdilation strategy and OHE severity [odds ratio (OR) = 0.683, 95% confidence interval (CI): 0.194-2.404, P = 0.552; Figure 3].
Figure 3 Forest plot of risk factors for hepatic encephalopathy severity in post-transjugular intrahepatic portosystemic shunt patients using ordinal logistic regression.
No significant association between the underdilation strategy and overt hepatic encephalopathy severity (odds ratio = 0.683, 95% confidence interval: 0.194-2.404, P = 0.552). OR: Odds ratio; CI: Confidence interval; BMI: Body mass index; MELD: Model for end-stage liver disease; TIPS: Transjugular intrahepatic portosystemic shunt; PPG: Portal venous pressure gradient.
OS: Of the 192 patients prior to PSM, 48 (25.0%) died during follow-up; after PSM, 38 of 156 patients (24.4%) died in the same period. Mortality rates were significantly lower in the ≤ 6 mm group than in the ≥ 7 mm group both pre-PSM (16.7% vs 32.4%, P = 0.012) and post-PSM (14.1% vs 34.6%, P = 0.003), with the difference becoming more pronounced after matching (Table 2). Kaplan-Meier OS curves for the post-PSM cohort demonstrated that patients in the ≤ 6 mm group experienced a significant mid-to-long-term survival benefit compared with those in the ≥ 7 mm group (log-rank P = 0.015; Figure 4).
Figure 4 Kaplan-Meier curves for overall survival after propensity score matching.
Patients in the ≤ 6 mm group experienced a significant mid-to-long-term survival benefit compared with those in the ≥ 7 mm group (log-rank P = 0.015).
Table 2 Outcome events before and after propensity score matching, n (%).
To further adjust for confounding factors impacting postoperative OS, a Cox regression analysis was conducted. Multivariable Cox regression confirmed that ≤ 6 mm stent underdilation was an independent protective factor for OS after adjusting for age, indications, CTP and MELD scores, liver cancer, ascites, and other related factors (hazard ratio = 0.422, 95%CI: 0.203-0.877, P = 0.021). The postoperative mortality risk in the ≤ 6 mm group was 0.422 times that of the ≥ 7 mm group, indicating that a smaller-diameter underdilation strategy can reduce the post-procedure mortality risk (Table 3).
Table 3 Prognostic factors identified via Cox regression after propensity score matching.
Impact of different underdilation levels on postoperative rebleeding and shunt dysfunction
This study focuses on the prognostic impact of different stent underdilation levels in patients with cirrhosis-related PH undergoing TIPS with 8-mm ePTFE-covered stents. Our findings indicate that stent underdilation to ≤ 6 mm vs ≥ 7 mm does not significantly affect the risk of variceal rebleeding or shunt dysfunction.
The core therapeutic goal of TIPS is to control variceal rebleeding and refractory ascites by reducing the PPG; consequently, stent diameter and balloon dilation directly affect the effectiveness of portal decompression[8]. Previous studies have primarily compared 8-mm and 10-mm stent diameters regarding hemodynamics and clinical outcomes, finding that larger stents more effectively reduced the PPG and yielded higher patency rates but potentially increased the risk of HE, despite comparable efficacy in preventing variceal rebleeding[18,19]. Our investigation examined the impact of stent underdilation on preventing variceal rebleeding by uniformly employing 8-mm ePTFE-covered stents. Our findings indicate that whether the underdilation diameter was ≤ 6 mm or ≥ 7 mm, the incidence of postprocedural rebleeding remained consistently low. This suggests that the more restricted shunting accomplished with a ≤ 6-mm balloon provides portal decompression efficacy for preventing variceal rebleeding comparable to that of a ≥ 7-mm balloon. According to TIPS guidelines, achieving a postoperative PPG < 12 mmHg or a baseline reduction ≥ 60% is the desired outcome for portal hemodynamic alterations[8,20]. Our study suggests that employing a smaller-diameter (≤ 6 mm) underdilation approach in the Asian population can meet this hemodynamic target (median postoperative PPG, 10-12 mmHg) without elevating the variceal rebleeding risk. This outcome holds substantial clinical implications, affirming the safety of this underdilation strategy.
Both groups exhibited low incidences of shunt dysfunction, with no significant differences observed, underscoring the intrinsic importance of the covered-stent material. The superior efficacy of ePTFE-covered materials in preventing pseudo-intimal hyperplasia and stent thrombosis has been well documented in landmark studies[5]. In our research, using covered stents appears to have overshadowed the incremental effects associated with a 1- to 2-mm diameter difference resulting from stent underdilation strategies. The inherent properties of the ePTFE covering are the primary determinants of long-term stent patency. The modest changes in underdilation diameters employed in this study did not negate these advantages; this aligns with accumulating evidence that the routine application of ePTFE-covered stents has substantially diminished the incidence of shunt dysfunction, rendering it a less frequent complication than in the bare-stent era.
Most prior studies have indicated that smaller TIPS stent diameters correlate with elevated rates of postoperative shunt dysfunction[9,14]. However, our data suggest that using ePTFE-covered stents may alleviate this issue. Given the advancements in modern materials science, reevaluating the conventional focus on TIPS-associated complications may be appropriate. This shift could redirect clinical attention from the limitations of smaller-diameter shunts in preventing rebleeding or shunt dysfunction toward optimizing other vital prognostic outcomes, particularly survival rates and HE incidence.
Association between underdilation and postoperative HE
In clinical practice, managing HE following TIPS presents a substantial challenge closely linked to the volume of portosystemic shunting. A primary strategy to alleviate this complication involves adjusting the shunt stent diameter. Theoretically, smaller-diameter stents should decrease blood flow through the portosystemic shunt, thereby reducing OHE risk[13,18]. However, our study revealed no statistically significant differences in the 1-year postoperative OHE incidence between the ≤ 6 mm and ≥ 7 mm underdilation groups, either before or after rigorous PSM. This finding contradicts the main hypothesis of prior studies concerning stent underdilation[16,21]. Additionally, further analysis using ordinal multivariable logistic regression confirmed that the degree of stent underdilation did not serve as an independent predictor of OHE severity. This comprehensive evaluation of incidence and severity indicates that underdilation strategies may not be the sole or primary factors influencing the complex pathophysiology of OHE after TIPS. To explain the lack of significant differences in OHE incidence between the groups, we propose the following three factors.
The “threshold effect” of the underdilation degree: In this study, ≥ 7 mm underdilation still represents a relatively conservative dilation strategy compared with previous studies comparing 8-mm and 10-mm stents, resulting in limited increases in shunting volume. With an 8-mm stent, the marginal differences in underdilation (≤ 6 mm vs ≥ 7 mm) are likely insignificant - physiologically insufficient to translate into substantial changes in clinical OHE incidence, especially when accounting for individual variations in portosystemic collateral circulation burden and hepatic metabolic reserves.
Impact of passive stent expansion: Some studies suggest that stent underdilation strategies are reliable and effective for preventing TIPS-related OHE. While this concept appears mechanistically plausible, the effect of subsequent passive stent expansion must be considered. Various studies have confirmed that ePTFE-covered stents, even when initially underdilated, gradually undergo passive expansion to their full nominal diameter over time[22,23]. In this study, using 8-mm ePTFE-covered stents with intentional underdilation (the ≤ 6 mm group) likely resulted in eventual passive expansion to 7-8 mm, narrowing the actual shunting volume differences between the groups. Therefore, absent measures to prevent subsequent passive dilation, underdilating with a balloon smaller than the nominal stent diameter may not produce a lasting change in shunt volume, thereby failing to sustain improvements in the clinical progression of OHE.
Equilibrium of baseline OHE risk among patients: OHE incidence is affected not only by stent diameter but also by additional factors such as age, liver function grade, spontaneous portosystemic shunts, malnutrition, inflammatory responses, and diabetes[24-27]. In this study, PSM effectively balanced the baseline characteristics between the groups, thereby minimizing confounding influences on postoperative OHE incidence. Moreover, lactulose was administered for primary prophylaxis in all post-TIPS patients, whereas rifaximin was not administered to any patients. This homogeneity in postoperative HE prophylaxis between the two groups further reduced study bias. Notably, OHE severity did not exhibit a significant correlation with the underdilation degree (OR = 0.683, 95%CI: 0.194-2.404, P = 0.552). This finding suggests that additional underlying factors may substantially affect postoperative OHE incidence, beyond variations in shunt diameter, and thus warrant further investigation. Therefore, we contend that for the Asian population, applying 8-mm ePTFE-covered stents during TIPS should not involve the indiscriminate adoption of an aggressive strategy aimed at reducing the shunt diameter to ≤ 6 mm as a primary method for preventing postoperative OHE. Determining the final shunt expansion diameter should be guided by a thorough clinical assessment.
Improvement in long-term survival with smaller-diameter underdilation
The primary finding of this study is the significant and independent association between stent underdilation to ≤ 6 mm and improved OS. This survival advantage remained evident even after rigorous adjustments for confounding factors through PSM and multivariable Cox regression, thereby confirming that the stent underdilation strategy serves as a robust, independent protective factor for postoperative survival. This result aligns with previous studies comparing 8-mm and 10-mm stents, which suggested that smaller diameters may confer greater survival benefits[10,14,15]. In this study, the rates of postoperative rebleeding and shunt dysfunction were comparable across the groups, and OHE incidence did not differ significantly. Consequently, the observed survival advantage cannot be ascribed to a reduction in these TIPS-related complications. Rather, it may result from the favorable regulation of early postoperative hemodynamic and metabolic changes facilitated by smaller-diameter shunts, thereby achieving a relatively balanced state between portal decompression and hepatic function preservation[10,28]. For the population examined, 6 mm and 7 mm may represent optimal delineation points; shunts measuring ≥ 7 mm could lead to increased portosystemic shunting, which diminishes effective hepatic perfusion, exacerbates liver dysfunction, and potentially contributes to hepatorenal syndrome or other organ failures as key determinants of mortality. Conversely, shunts measuring ≤ 6 mm may provide a more balanced decompression, sufficiently lowering the portal pressure to prevent rebleeding while maintaining the hepatopetal blood flow essential for long-term hepatic synthetic and metabolic function.
Furthermore, patients with cirrhosis frequently exhibit cirrhotic cardiomyopathy[29]. After TIPS placement, the substantial venous return to the right atrium induces a “tsunami effect”, which acutely elevates cardiac preload and may trigger heart failure[30,31]. The European Association for the Study of the Liver guidelines also recommend using the small-diameter stents to alleviate cardiac load and reduce mortality risk[8]. In this study, the effects of ≤ 6 mm underdilation on systemic hemodynamic changes were less pronounced, particularly among elderly patients or those with preexisting cardiac conditions. This approach may diminish the risk of inducing or worsening incipient cardiac insufficiency, thereby serving as a protective factor against mortality and improving prognosis.
Key indicators of the systemic inflammatory response after TIPS, such as interleukin-6, may exhibit a continuous decline. This reduction is independently associated with a lower incidence of acute-on-chronic liver failure and liver disease-related mortality; thus, substantial improvements in systemic inflammation emerge as a critical mechanism for survival benefits after TIPS[32,33]. In this study, shunt underdilation to ≤ 6 mm achieved a milder reduction in portal pressure, potentially mitigating inflammatory responses while avoiding new inflammatory stimuli induced by excessive shunting and subsequent ischemia-reperfusion injury. This approach led to greater improvements in systemic inflammation, ultimately translating into a survival benefit.
Additionally, the multivariable Cox regression analysis revealed that Child-Pugh classification C, concomitant liver cancer, and extensive ascites are independent risk factors for mortality, aligning with previous research[24,34,35]. These results indicate that postoperative survival is influenced not only by the stent strategy but also by the baseline liver function reserve and comorbidities, underscoring the importance of thorough assessments in clinical decision-making.
Study limitations
Conducted as a single-center retrospective cohort study, this research utilized PSM to mitigate known baseline discrepancies. However, PSM can only account for measured confounders, leaving unmeasured factors that may affect the observed survival benefits, which poses challenges for causal inference. For example, because diuretic regimens are individualized based on patient status, eliminating such bias exclusively through PSM adjustment is difficult, representing an inevitable limitation of retrospective studies. Furthermore, findings from a single center have limited generalizability, thereby reducing external validity and reproducibility. Given the matched sample size of 78 patients per group, the statistical power may be inadequate to evaluate secondary endpoints such as rebleeding and shunt dysfunction, which may explain the absence of statistically significant differences in these outcomes. Consequently, larger prospective multicenter studies are necessary for validation.
CONCLUSION
The clinical imperative to reduce post-TIPS OHE rates has spurred extensive research into strategies for shunt regulation. Postoperative survival rates may serve as a more critical metric than OHE incidence when evaluating shunt efficacy[10,36,37]. Additionally, the choice of underdilation strategy can substantially influence patient outcomes after TIPS. The underdilation technique, especially to smaller diameters (≤ 6 mm), appears to offer a more favorable risk-benefit profile; such strategies may mitigate the adverse events associated with larger stent diameters, thereby improving the survival rates observed in this and other investigations. In summary, our study demonstrated that using 8-mm ePTFE-covered stents with TIPS underdilation to ≤ 6 mm vs ≥ 7 mm did not result in significant differences in postoperative rebleeding, shunt dysfunction, or OHE incidence. However, it revealed a substantial reduction in mortality risk for patients with stent underdilation to ≤ 6 mm. This strategy appears to recalibrate the risk-benefit balance associated with TIPS using 8-mm ePTFE-covered stents, yielding superior mid- to long-term survival benefits for patients.
Lv Y, Yang Z, Liu L, Li K, He C, Wang Z, Bai W, Guo W, Yu T, Yuan X, Zhang H, Xie H, Yao L, Wang J, Li T, Wang Q, Chen H, Wang E, Xia D, Luo B, Li X, Yuan J, Han N, Zhu Y, Niu J, Cai H, Xia J, Yin Z, Wu K, Fan D, Han G; AVB-TIPS Study Group. Early TIPS with covered stents versus standard treatment for acute variceal bleeding in patients with advanced cirrhosis: a randomised controlled trial.Lancet Gastroenterol Hepatol. 2019;4:587-598.
[RCA] [PubMed] [DOI] [Full Text][Cited by in Crossref: 207][Cited by in RCA: 193][Article Influence: 27.6][Reference Citation Analysis (1)]
Trebicka J, Gu W, Ibáñez-Samaniego L, Hernández-Gea V, Pitarch C, Garcia E, Procopet B, Giráldez Á, Amitrano L, Villanueva C, Thabut D, Silva-Junior G, Martinez J, Genescà J, Bureau C, Llop E, Laleman W, Palazon JM, Castellote J, Rodrigues S, Gluud L, Ferreira CN, Barcelo R, Cañete N, Rodríguez M, Ferlitsch A, Mundi JL, Gronbaek H, Hernández-Guerra M, Sassatelli R, Dell'Era A, Senzolo M, Abraldes JG, Romero-Gómez M, Zipprich A, Casas M, Masnou H, Primignani M, Weiss E, Catalina MV, Erasmus HP, Uschner FE, McCoy MS, Brol MJ, Praktiknjo M, Chang J, Krag A, Nevens F, Calleja JL, Robic MA, Conejo I, Albillos A, Rudler M, Alvarado E, Guardascione MA, Tantau M, Bosch J, Torres F, Pavesi M, Garcia-Pagán JC, Jansen C, Bañares R; International Variceal Bleeding Observational Study Group and Baveno Cooperation. Rebleeding and mortality risk are increased by ACLF but reduced by pre-emptive TIPS.J Hepatol. 2020;73:1082-1091.
[RCA] [PubMed] [DOI] [Full Text][Cited by in Crossref: 156][Cited by in RCA: 154][Article Influence: 25.7][Reference Citation Analysis (19)]
Riggio O, Ridola L, Angeloni S, Cerini F, Pasquale C, Attili AF, Fanelli F, Merli M, Salvatori FM. Clinical efficacy of transjugular intrahepatic portosystemic shunt created with covered stents with different diameters: results of a randomized controlled trial.J Hepatol. 2010;53:267-272.
[RCA] [PubMed] [DOI] [Full Text][Cited by in Crossref: 125][Cited by in RCA: 117][Article Influence: 7.3][Reference Citation Analysis (3)]
Luca A, Miraglia R, Maruzzelli L, D'Amico M, Tuzzolino F. Early Liver Failure after Transjugular Intrahepatic Portosystemic Shunt in Patients with Cirrhosis with Model for End-Stage Liver Disease Score of 12 or Less: Incidence, Outcome, and Prognostic Factors.Radiology. 2016;280:622-629.
[RCA] [PubMed] [DOI] [Full Text][Cited by in Crossref: 48][Cited by in RCA: 50][Article Influence: 5.0][Reference Citation Analysis (2)]
Wang Q, Lv Y, Bai M, Wang Z, Liu H, He C, Niu J, Guo W, Luo B, Yin Z, Bai W, Chen H, Wang E, Xia D, Li X, Yuan J, Han N, Cai H, Li T, Xie H, Xia J, Wang J, Zhang H, Wu K, Fan D, Han G. Eight millimetre covered TIPS does not compromise shunt function but reduces hepatic encephalopathy in preventing variceal rebleeding.J Hepatol. 2017;67:508-516.
[RCA] [PubMed] [DOI] [Full Text][Cited by in Crossref: 88][Cited by in RCA: 167][Article Influence: 18.6][Reference Citation Analysis (1)]
Lee EW, Eghtesad B, Garcia-Tsao G, Haskal ZJ, Hernandez-Gea V, Jalaeian H, Kalva SP, Mohanty A, Thabut D, Abraldes JG. AASLD Practice Guidance on the use of TIPS, variceal embolization, and retrograde transvenous obliteration in the management of variceal hemorrhage.Hepatology. 2024;79:224-250.
[RCA] [PubMed] [DOI] [Full Text][Cited by in Crossref: 121][Cited by in RCA: 138][Article Influence: 69.0][Reference Citation Analysis (0)]
Schepis F, Vizzutti F, Garcia-Tsao G, Marzocchi G, Rega L, De Maria N, Di Maira T, Gitto S, Caporali C, Colopi S, De Santis M, Arena U, Rampoldi A, Airoldi A, Cannavale A, Fanelli F, Mosconi C, Renzulli M, Agazzi R, Nani R, Quaretti P, Fiorina I, Moramarco L, Miraglia R, Luca A, Bruno R, Fagiuoli S, Golfieri R, Torricelli P, Di Benedetto F, Belli LS, Banchelli F, Laffi G, Marra F, Villa E. Under-dilated TIPS Associate With Efficacy and Reduced Encephalopathy in a Prospective, Non-randomized Study of Patients With Cirrhosis.Clin Gastroenterol Hepatol. 2018;16:1153-1162.e7.
[RCA] [PubMed] [DOI] [Full Text][Cited by in Crossref: 67][Cited by in RCA: 117][Article Influence: 14.6][Reference Citation Analysis (3)]
Tiede A, Stockhoff L, Liu Z, Rieland H, Mauz JB, Ohlendorf V, Bremer B, Witt J, Kraft A, Cornberg M, Hinrichs JB, Meyer BC, Wedemeyer H, Xu CJ, Falk CS, Maasoumy B. Insertion of a transjugular intrahepatic portosystemic shunt leads to sustained reversal of systemic inflammation in patients with decompensated liver cirrhosis.Clin Mol Hepatol. 2025;31:240-255.
[RCA] [PubMed] [DOI] [Full Text] [Full Text (PDF)][Cited by in Crossref: 1][Cited by in RCA: 20][Article Influence: 20.0][Reference Citation Analysis (0)]
Roccarina D, Saltini D, Adotti V, Rosi M, Senzolo M, Nardelli S, Bianchini M, Biribin L, Caporali C, Margherita F, Ragozzino L, Guasconi T, Casari F, Gioia S, Campani C, Prampolini F, Ingravallo A, Gitto S, Aspite S, Arena U, Citone M, Gaggini M, Ridola L, Barbiero G, De Masi S, Riggio O, Merli M, Fanelli F, Montagnese S, Marra F, Schepis F, Vizzutti F. End-procedural adherence to recommended hemodynamic targets does not improve the outcome of elective TIPS in patients with cirrhosis.Hepatology. 2025;82:1155-1171.
[RCA] [PubMed] [DOI] [Full Text][Cited by in Crossref: 9][Cited by in RCA: 10][Article Influence: 10.0][Reference Citation Analysis (0)]
Saltini D, Guasconi T, Ingravallo A, Indulti F, Caporali C, Gitto S, Falcini M, Bianchini M, Cuffari B, Scoppettuolo M, Spadaccini R, Prampolini F, Casari F, De Maria N, Marra F, Colecchia A, Vizzutti F, Schepis F. Underdilated neoadjuvant-TIPS in patients with cirrhosis and portal hypertension candidates to operative interventions.Dig Liver Dis. 2024;56:S64.
[PubMed] [DOI] [Full Text]
