Covered versus uncovered self-expandable metal stent for palliation of primary malignant extrahepatic biliary strictures: a randomized multicenter study

Efficacy and safety of uncovered self-expandable metal stents for distal malignant biliary obstruction in unresectable non-pancreatic cancer

Objectives

The efficacy of uncovered self-expandable metal stents (UCSEMS) versus fully covered self-expandable metal stents for distal malignant biliary obstruction remains controversial. Additionally, the heterogeneity of the disease conditions has been indicated in previous studies because pancreatic and non-pancreatic cancers have different characteristics in clinical course. Therefore, the etiology of biliary obstruction necessitates investigations stratified by primary disease. This study aimed to evaluate the outcomes of UCSEMS, specifically for non-pancreatic cancer-induced distal malignant biliary obstruction.

Methods

We conducted a single-center retrospective review to evaluate the time to recurrent biliary obstruction and frequency of adverse events (AEs) in patients receiving UCSEMS for unresectable non-pancreatic cancer-induced malignant biliary obstruction.

Results

Overall, 32 patients were enrolled in the study between January 2016 and December 2023. The median time to recurrent biliary obstruction was 140 days. AE rates were low at 3.1% for both pancreatitis and cholecystitis, suggesting a potential benefit of UCSEMS in reducing post-procedural AEs.

Conclusion

UCSEMS may reduce the risk of post-procedural AEs and should be considered in patients at high risk of post-endoscopic retrograde cholangiopancreatography pancreatitis. However, the patency period may be shorter, necessitating future comparative research with fully covered self-expandable metal stents to determine the optimal stent choice.

Biliary drainage in patients with malignant distal biliary obstruction: results of an Italian consensus conference

BACKGROUND

Malignant Distal Biliary Obstruction (MBDO) is a common event occurring along the natural history of both pancreatic cancer and cholangiocarcinoma. Epidemiological and biological features make MBDO one of the key elements of the clinical management of patients suffering for of pancreatic cancer or cholangiocarcinoma. The development of dedicated biliary lumen-apposing metal stents (LAMS) is changing the clinical work up of patients with MBDO. i-EUS is an Italian network of clinicians and scientists with a special interest in biliopancreatic endoscopy, EUS in particular.

METHODS

The scientific methodology was chosen in line with international guidance and in a fashion similar to those applied by broader scientific associations. PICO questions were elaborated and subsequently voted by a broad panel of experts within a simplified Delphi process.

RESULTS AND CONCLUSIONS

The manuscripts describes the results of a consensus conference organized by i-EUS with the aim of providing an evidence based-guidance for the appropriate use of the techniques in patients with MBDO.

Meta-analysis of the effectiveness of early endoscopic treatment of Acute biliary pancreatitis based on lightweight deep learning model

BACKGROUND

Acute biliary pancreatitis (ABP) is a clinical common acute abdomen. After the first pancreatitis, relapse rate is high, which seriously affects human life and health and causes great economic burdens to family and society. According to a great many research findings, endoscopic retrograde cholangiopancreatography (ERCP) is an effective treatment method. However, whether ERCP should be performed in early stage of ABP is still controversial in clinical practice.

METHODS

Related articles were retrieved from Pubmed, Web of Science core library, Nature, Science Direct, and other databases published from January 2000 until now. The keywords included early ERCP, delayed ERCP, ABP, laparoscopy, and cholecystectomy, all which were connected by "or" and "and". The language of articles was not restricted during the retrieval and Review Manager5.3 was employed to perform meta-analysis of experimental data. Finally, a total of 8 eligible articles were selected, including 8,801 patients.

RESULTS

The results of the meta-analysis demonstrated that no remarkable differences were detected in the incidence of complications, mortality, and operation time between patients undergoing ERCP in early stage and those receiving delayed ERCP. However, the hospitalization time of patients in experimental group was notably shorter than that among patients in control group.

CONCLUSINS

Early ERCP treatment is as safe as late ERCP treatment for biliary pancreatitis, and can significantly shorten the hospital stay. Hence, the therapy was worthy of clinical promotion. The research findings provided reference and basis for clinical treatment of relevant diseases.

Covered Versus Uncovered Metal Stents for the Drainage of the Malignant Distal Biliary Obstruction With ERCP: A Systematic Review and Meta-Analysis

INTRODUCTION AND AIM

Unresectable malignant distal biliary obstruction is a condition that should be treated with drainage and clearance of the biliary duct. self-expanded metal stents (SEMS) are known to be better and more effective than plastic stents because the patency is longer. The actual evidence is insufficient to recommend if it is better the use of SEMSu over SEMSc or vice versa for the drainage of the malignant distal biliary obstruction during ERCP. We performed a systematic review and meta-analyses to demonstrate if exists superiority between one or other type of SEMS performed by ERCP.

MATERIALS AND METHODS

We conducted a systematic review in different databases, such as PubMed, Cochrane, Medline, and OVID database. A search was made of all studies published up to May 2023.

RESULTS

Seven studies were analyzed. A total of 1070 patients were included. Of the total of patients, 48.9% were male. The cumulative stent patency, the failure rate, the survival probably and the adverse events rate, were similar between SEMSc and SEMSu groups. The stent migration rate was higher in the SEMSc group (RR=2.34 [95% CI: 1.35-4.08]). The tumor overgrowth was higher in the SEMSc group (RR=2.05 [95% CI: 1.13-3.72]). The tumor ingrowth was higher in the SEMSu group (RR=0.25 [95% CI: 0.11-0.61]).

CONCLUSIONS

The conclusions of our study show that there are no differences between the use of uncovered SEMS and covered SEMS for palliative treatment of distal biliopancreatic obstructions, and it has no impact on mortality or patient survival. New functional studies regarding the type of stent cover, radial force or length thereof are required.

Braided-type stent versus laser-cut-type stent for patients with unresectable distal malignant biliary obstruction: a randomized controlled trial

BACKGROUND AND AIMS

Fully covered self-expandable metallic stents (SEMSs) are laser-cut (L) or braided (B); however, it remains unclear which approach is more effective for distal malignant biliary obstruction (DMBO). This study compared the clinical outcomes of using L-type and B-type stents because we believe that recurrent biliary obstruction (RBO) is less likely to occur with L-type stents.

METHODS

Patients diagnosed with unresectable DMBO were randomly assigned to groups L and B in a stratified block fashion, and outcomes were compared. The primary outcome was the rate of RBO within 1 year; secondary outcomes were adverse events, clinical success rate, time to RBO (TRBO), and overall survival.

RESULTS

Of the 60 enrolled participants, 56 (group L, n = 27; group B, n = 29) were included. The rates of RBO within 1 year were 44.4% and 17.2% in groups L and B, respectively (odds ratio, 2.57; 95% confidence interval [CI], 1.045-6.353). Early adverse events, which improved with conservative treatment, included pancreatitis (n = 4) in group L and pancreatitis (n = 3) and cholecystitis (n = 1) in group B (P = .913). The median TRBO (220 days [95% CI, 56-272] vs 418 days [95% CI, 232-454]) was significantly longer in group B than in group L (log-rank test, P = .0118). The median overall survival (group L, 158 days; group B, 204 days) after stenting was not significantly different between groups (P = .8544).

CONCLUSIONS

In the setting of DMBO, B-type stents are associated with less recurrent obstruction than L-type stents, although there was no difference in safety. (UMIN Clinical Trials Registry number: UMIN000027239.).

Aspirin exposure and its association with metal stent patency in malignant distal biliary obstruction: a large international multicenter propensity score-matched study

BACKGROUND AND AIMS

Stent dysfunction is common after ERCP with self-expandable metal stent (SEMS) insertion for malignant distal biliary obstruction (MDBO). Chronic aspirin (acetylsalicylic acid; ASA) exposure has been previously shown to potentially decrease this risk. We aim to further ascertain the protective effect of ASA and to identify other predictors of stent dysfunction.

METHODS

This multicenter retrospective cohort study was conducted at 9 sites in Canada and 1 in the United States. Patients with MDBO who underwent ERCP with SEMS placement between January 2014 and December 2019 were included and divided into 2 cohorts: ASA exposed (ASA-E) and ASA unexposed (ASA-U). Propensity-score matching (PSM) was performed to limit selection bias. Matched variables were age, sex, tumor stage, and type of metal stent. The primary outcome was the hazard rate of stent dysfunction. A multivariable Cox proportional hazards model was used to identify independent predictors of stent dysfunction.

RESULTS

Of 1396 patients assessed, after PSM 496 patients were analyzed (248 ASA-E and 248 ASA-U). ERCP with SEMS placement was associated with a high clinical success of 82.2% in ASA-E and 81.2% in ASA-U cohorts (P = .80). One hundred eighty-four patients had stent dysfunction with a mean stent patency time of 229.9 ± 306.2 days and 245.4 ± 241.4 days in ASA-E and ASA-U groups, respectively (P = .52). On multivariable analysis, ASA exposure did not protect against stent dysfunction (hazard ratio [HR], 1.25; 95% confidence interval [CI], .96-1.63). An etiology of pancreatic cancer (HR, 1.36; 95% CI, 1.15-1.61) predicted stent dysfunction, whereas cancer therapy was protective (HR, .73; 95% CI, .55-.96). Chronic ASA use was not associated with an increased risk for adverse events including bleeding, post-ERCP pancreatitis, and perforation.

CONCLUSIONS

In this large, multicenter study using PSM, chronic exposure to ASA did not protect against stent dysfunction in MDBO. Instead, the analysis revealed that the etiology of pancreatic cancer was an independent predictor of stent dysfunction and cancer therapy was protective.

Anchoring fins of fully covered self-expandable metal stents affect pull-out force and stent migration

BACKGROUND AND AIMS

Stent migration and subsequent adverse events are frequently observed in the use of fully covered self-expandable metal stents (FCSEMSs) for distal biliary stenosis. In this study, we identified predictors for stent migration based on biomechanical stent characteristics and associated these findings with clinical outcomes.

METHODS

The migration resistance of FCSEMSs was quantified by measuring the pull-out force. We analyzed a single-center retrospective cohort of 178 FCSEMSs for treatment success and adverse events occurring during 180 days of follow-up.

RESULTS

Biomechanical measurements revealed a 4-fold higher migration resistance of FCSEMSs with anchoring fins (AF-FCSEMSs; Fmax = 14.2 ± .1 N) compared with FCSEMSs with flared ends (FE-FCSEMSs; Fmax = 3.8 ± 1.0 N; P < .0001). Clinically, AF-FCSEMSs showed lower rates of migration compared with FE-FCSEMSs (5% vs 34%, P < .0001). Unscheduled ERCP procedures because of stent dysfunction were less frequent in the AF group compared with the FE group (15% vs 29%, P = .046). Cholangitis because of stent dysfunction was observed in 5% of the AF group compared with 19% in the FE group (P = .02). Stent patency rates at 1, 3, and 6 months were higher in the AF group (96%, 90%, and 80%, respectively) compared with the FE group (90%, 74%, and 66%; log-rank test: P = .03).

CONCLUSIONS

The pull-out force as a biomechanical stent property predicts the migration resistance of FCSEMSs in distal biliary stenosis and may thus be used to classify stents for this application. AF-FCSEMSs showed a significantly lower rate of migration and adverse events compared with FE-FCSEMSs.

Fully covered versus partially covered self-expandable metal stents for palliation of distal malignant biliary obstruction: a systematic review and meta-analysis

BACKGROUND AND AIMS

Self-expandable metal stents (SEMSs) are standardly used for distal malignant biliary obstruction (dMBO). Although data suggest that covered versus uncovered SEMSs increase the time to recurrent biliary obstruction (TRBO), no data are available for fully covered (FC) versus partially covered (PC) designs.

METHODS

PubMed, Scopus, and Cochrane databases were screened up to January 2023 for studies concerning dMBO treated by an FC- or PC-SEMS and describing adverse events (AEs), recurrences, or TRBO for specific design subpopulations. Pooled proportions or means were calculated using a random-effects model. Several subanalyses were preplanned, including a subanalysis restricted to prospective studies and unresectable diseases. Heterogeneity and publication bias were explored. Standardized differences (d-values) were calculated between groups.

RESULTS

From 1290 records, 62 studies (3327 using FC-SEMSs and 2322 using PC-SEMSs) were included. FC- versus PC-SEMSs showed negligible differences in the rate of total AEs (12% vs 9.9%) and all specific AEs, including cholecystitis (2.5% vs 2.6%). In a subanalysis restricted to prospective studies and unresectable diseases, the rate of RBO was comparable between FC-SEMSs (27.3% [95% confidence interval {CI}, 23.7-31.2], I2 = 35.34%) and PC-SEMSs (25.3% [95% CI, 20.2-30.7], I2 = 85.09%), despite small differences (d-values between .186 and .216) in the rate of ingrowth (.5% vs 2.9%) favoring FC-SEMSs and migration (9.8% vs 4.3%) favoring PC-SEMSs. TRBO was shorter for FC-SEMSs (238 days [95% CI, 191-286], I2 = 63.1%) versus PC-SEMSs (369 days [95% CI, 290-449], I2 = 71.9%; d-value = .116).

CONCLUSIONS

Despite considerable heterogeneity and small standardized differences, PC-SEMSs consistently exhibited longer TRBO than FC-SEMSs across analyses, without any other differences in AE rates, potentially proposing PC-SEMSs as the standard comparator and TRBO as the primary outcome for future randomized studies on dMBO. (Clinical trial registration number: CRD42023393965.).

Characteristics of four commonly used self-expanding biliary stents: an in vitro study

BACKGROUND

Knowledge of the characteristics of self-expanding metal stents (SEMSs) is essential during selection process to ensure the best therapeutic outcomes for patients with malignant biliary obstruction. The aim of this study was to evaluate the characteristics of four commonly used SEMSs.

METHODS

This in vitro study analyzed the radial force (RF), crush resistance (CR), axial force (AF), conformability, surface quality, foreshortening, and radiopacity of the following SEMSs: uncovered Wallflex™, EGIS single bare, Zilver 635®, and E-Luminexx™. Two samples of each SEMS type were included in this study, all having identical specifications with a diameter of 10 mm and a length of 6 cm. One sample from each type was analyzed for surface quality, followed by CR, conformability, and foreshortening. The other sample was analyzed for radiopacity, followed by RF and AF.

RESULTS

The uncovered Wallflex™ exhibited low RF, high CR, high AF, good conformability, poor surface quality, high foreshortening, and good radiopacity. The EGIS single bare demonstrated high RF, high CR, low AF, moderate conformability, good surface quality, high foreshortening, and poor radiopacity. The Zilver 635® displayed moderate RF, low CR, low AF, moderate conformability, moderate surface quality, no foreshortening, and good radiopacity. The E-Luminexx™ showed high RF, moderate CR, high AF, poor conformability, poor surface quality, no foreshortening, and good radiopacity.

CONCLUSIONS

There was considerable variation in the characteristics among the four evaluated SEMSs. These characteristics should be carefully considered during selection to ensure optimal therapeutic outcomes for patients.

RELEVANCE STATEMENT

The selection of self-expanding metal stents for treating malignant biliary obstruction requires careful consideration of various characteristics, including their radial force, crush resistance, axial force, conformability, surface quality, foreshortening, and radiopacity.

KEY POINTS

• The characteristics of self-expanding metal stents (SEMSs) can vary considerably. • Specific situations may warrant the use of SEMSs with particular characteristics over others. • Characteristics of SEMSs must be considered during selection for optimal outcomes.

Efficacy of multi-hole self-expandable metal stent compared to fully covered and uncovered self-expandable metal stents in patients with unresectable malignant distal biliary obstruction: a propensity analysis

BACKGROUND AND AIMS

Self-expandable metal stent (SEMS) insertion is the standard palliative treatment for unresectable malignant extrahepatic biliary obstruction (MBO). Drawbacks of conventional fully covered SEMS (FCSEMS) and uncovered SEMS (USEMS) include stent migration and tumor ingrowth, respectively. This study aimed to compare stent patency in MBO with the newly design multi-hole SEMS (MHSEMS), which has multiple small side holes in the stent membrane, with conventional FCSEMS and UCSEMS.

PATIENTS AND METHODS

This retrospective study using a propensity score matching design and stent patency times of 40 patients with MHSEMS was compared to 40 and 34 patients with FCSEMS and UCSEMS during the same period, respectively. Secondary outcomes were procedure-related adverse events, clinical success rate, time to recurrent biliary obstruction (RBO), and etiology of RBO. RBO was compared using Kaplan-Meier analysis.

RESULTS

Baseline characteristics after matching were comparable among the 3 groups. RBO rates were 21%, 37%, and 55% for MHSEMS, FCSEMS, and UCSEMS, respectively (p = 0.014), at a mean time of 479, 353, and 306 days, respectively (MHSEMS vs UCSEMS, p = 0.002). Rate of tumor ingrowth was highest in the UCSEMS group (42.4% vs 13.2% in MHSEMS; p = 0.005 and vs 0% in FCSEMS; p < 0.001). Stent migration rate was highest in the FCSEMS group at 15.8% vs 2.6% in MHSEMS (p = 0.047) and 0% in UCSEMS (p = 0.005).

CONCLUSION

MHSEMS provided the longest stent patency time with lowest RBO rate compared to conventional SEMS by showing a lower stent migration rate than FCSEMS and a lower tumor ingrowth rate than UCSEMS.

Endoscopic Ultrasound-Guided Biliary Drainage of First Intent With a Lumen-Apposing Metal Stent vs Endoscopic Retrograde Cholangiopancreatography in Malignant Distal Biliary Obstruction: A Multicenter Randomized Controlled Study (ELEMENT Trial)

BACKGROUND & AIMS

Endoscopic ultrasound-guided choledochoduodenostomy with a lumen-apposing metal stent (EUS-CDS) is a promising modality for management of malignant distal biliary obstruction (MDBO) with potential for better stent patency. We compared its outcomes with endoscopic retrograde cholangiopancreatography with metal stenting (ERCP-M).

METHODS

In this multicenter randomized controlled trial, we recruited patients with MDBO secondary to borderline resectable, locally advanced, or unresectable peri-ampullary cancers across 10 Canadian institutions and 1 French institution. This was a superiority trial with a noninferiority assessment of technical success. Patients were randomized to EUS-CDS or ERCP-M. The primary end point was the rate of stent dysfunction at 1 year, considering competing risks of death, clinical failure, and surgical resection. Analyses were performed according to intention-to-treat principles.

RESULTS

From February 2019 to February 2022, 144 patients were recruited; 73 were randomized to EUS-CDS and 71 were randomized to ERCP-M. The mean (SD) procedure time was 14.0 (11.4) minutes for EUS-CDS and 23.1 (15.6) minutes for ERCP-M (P < .01); 40% of the former was performed without fluoroscopy. Technical success was achieved in 90.4% (95% CI, 81.5% to 95.3%) of EUS-CDS and 83.1% (95% CI, 72.7% to 90.1%) of ERCP-M with a risk difference of 7.3% (95% CI, -4.0% to 18.8%) indicating noninferiority. Stent dysfunction occurred in 9.6% vs 9.9% of EUS-CDS and ERCP-M cases, respectively (P = .96). No differences in adverse events, pancreaticoduodenectomy and oncologic outcomes, or quality of life were noted.

CONCLUSIONS

Although not superior in stent function, EUS-CDS is an efficient and safe alternative to ERCP-M in patients with MDBO. These findings provide evidence for greater adoption of EUS-CDS in clinical practice as a complementary and exchangeable first-line modality to ERCP in patients with MDBO.

CLINICALTRIALS

gov, Number: NCT03870386.

Uncovered versus fully covered self-expandable metal stents for the management of distal malignant biliary obstruction

BACKGROUND AND AIM

Self-expandable metal stents (SEMSs) are widely used for palliation of distal malignant biliary obstruction (dMBO). However, previous studies comparing the outcomes between uncovered SEMSs (UCSEMSs) and fully covered SEMSs (FCSEMSs) report conflicting results. This large cohort study aimed to compare the clinical outcomes between UCSEMSs and FCSEMSs for dMBO.

METHODS

A retrospective cohort study was performed in patients with dMBO who underwent either UCSEMS or FCSEMS placement between May 2017 and May 2021. Primary outcomes were rates of clinical success, adverse events (AEs), and unplanned endoscopic reintervention. Secondary outcomes were types of AEs, intervention-free stent patency, and management and outcomes of stent occlusion.

RESULTS

The cohort included 454 patients (364 in the UCSEMS group and 90 in the FCSEMS group). Median follow-up duration was 9.6 months and was similar between the 2 groups. Use of UCSEMSs and FCSEMSs had comparable clinical success (P = .250). However, use of UCSEMSs had significantly higher rates of AEs (33.5% vs 21.1%; P = .023) and unplanned endoscopic reintervention (27.0% vs 11.1%; P = .002). UCSEMSs had a higher rate of stent occlusion (26.9% vs 8.9%; P < .001) and shorter median time to stent occlusion (4.4 months vs 10.7 months; P = .002). Stent reintervention-free survival was higher in the FCSEMS group. FCSEMSs had a significantly higher rate of stent migration (7.8% vs 1.1%; P < .001), but patients in the FCSEMS group had similar rates of cholecystitis (.3% vs 1.1%; P = .872) and post-ERCP pancreatitis (6.3% vs 6.6%; P = .90). When UCSEMSs did occlude, placement of a coaxial plastic stent had a higher rate of stent reocclusion compared with coaxial SEMS placement (46.7% vs 19.7%; P = .007).

CONCLUSION

FCSEMSs should be considered for the palliation of dMBO because of lower rates of AEs, longer patency rates, and lower rates of unplanned endoscopic intervention.

Evaluation of the mechanical properties of current biliary self-expandable metallic stents: axial and radial force, and axial force zero border

BACKGROUND/AIMS

Mechanical properties (MPs) and axial and radial force (AF and RF) may influence the efficacy and complications of self-expandable metallic stent (SEMS) placement. We measured the MPs of various SEMSs and examined their influence on the SEMS clinical ability.

METHODS

We evaluated the MPs of 29 types of 10-mm SEMSs. RF was measured using a conventional measurement device. AF was measured using the conventional and new methods, and the correlation between the methods was evaluated.

RESULTS

A high correlation in AFs was observed, as measured by the new and conventional manual methods. AF and RF scatterplots divided the SEMSs into three subgroups according to structure: hook-and-cross-type (low AF and RF), cross-type (high AF and low RF), and laser-cut-type (intermediate AF and high RF). The hook-and-cross-type had the largest axial force zero border (>20°), followed by the laser-cut and cross types.

CONCLUSION

MPs were related to stent structure. Hook-and-cross-type SEMSs had a low AF and high axial force zero border and were considered safest because they caused minimal stress on the biliary wall. However, the increase in RF must be overcome.

Efficacy and complications of inoperable malignant distal biliary obstruction treatment by metallic stents: fully covered or uncovered?

Obstructive jaundice caused by malignant distal biliary obstruction is a common clinical symptom in patients with inoperable biliary-pancreatic cancer. Endoscopic retrograde cholangiopancreatography (ERCP)-guided stent implantation is an effective treatment for obstructive jaundice. Internal stent drainage is more physiologic and associated with a better quality of life than external stent drainage methods such as percutaneous transhepatic gallbladder drainage or percutaneous transhepatic cholangiodrainage. Self-expanding metallic stents, which may be covered and uncovered, are commonly used. However, some uncertainties remain regarding the selection of metallic stents, including drainage patency time, clinical effect, stent migration, and post-operative complications such as pancreatitis, bleeding, and cholecystitis. This review aims to summarize the current progress and controversies surrounding the use of covered or uncovered metallic stents in inoperable common biliary obstruction via ERCP.

Efficacy and safety of covered versus uncovered self‑expandable metal stents for the palliative treatment of malignant distal biliary stricture: A long‑term retrospective study

Both covered self-expandable metal stents (CSEMSs) and uncovered self-expandable metal stents (USEMSs) have been tried in the palliation of malignant distal biliary strictures by means of endoscopic retrograde cholangiopancreatography (ERCP); however, the comparison of efficacy and safety between them remains contested. To the best of our knowledge, no similar studies have assessed this in the Chinese population. In the present study, the clinical and endoscopic data of 238 patients (CSEMSs, n=55; USEMSs, n=183) with malignant distal biliary strictures from 2014 to 2019 were collected. The efficacy indicated by mean stent patency, stent patency rate, mean patient survival time and survival rate, and the safety indicated by adverse events after CSEMS or USEMS placement were retrospectively analyzed and compared. The mean stent patency time was significantly longer in the CSEMSs group than that in the USEMSs group (262.8±195.3 days vs. 169.5±155.7 days, P=0.002). The mean patient survival time was significantly longer in the CSEMSs group than that in the USEMSs group (273.9±197.6 days vs. 184.9±167.6 days, P=0.003). The stent patency rate and patient survival rate were significantly higher in the CSEMSs group than those in the USEMSs group at 6 and 12 months, but not at 1 and 3 months. There was no significant difference in stent dysfunction and adverse events between the two groups, although post-ERCP pancreatitis (PEP) occurred more frequently in the CSEMSs group than in the USEMSs group (18.1% vs. 8.8%, P=0.049). In conclusion, CSEMSs were better than USEMSs for malignant distal biliary strictures in terms of stent patency time and patient survival time as well as stent patency rate and patient survival rate in the long term (>6 months). Adverse events in the two groups occurred at a similar rate, although the incidence of PEP was higher in the CSEMSs group.

Effect of ursodeoxycholic acid after self-expandable metal stent placement in malignant distal biliary obstruction: a propensity score-matched cohort analysis

BACKGROUND AND AIMS

Sludge occlusion is a primary reason for recurrent biliary obstruction (RBO) after self-expandable metallic stent (SEMS) placement. However, the efficacy of ursodeoxycholic acid (UDCA) for SEMS occlusion remains unexplored to date. This study aimed to evaluate the efficacy of UDCA after SEMS placement for malignant distal biliary obstruction (MDBO).

METHODS

Three hundred fifty-four patients were included, of which 60 received UDCA. Additionally, we conducted a propensity score-matched cohort analysis on 110 patients with SEMS placement for MDBO to reduce selection bias. Patients were categorized into 2 groups of 55 each, based on whether they received UDCA. In the UDCA group, the treatment was administered for more than a month. The primary endpoint was the time to RBO (TRBO) after SEMS placement. The secondary endpoint was to evaluate SEMS occlusion rate and early adverse events (AEs).

RESULTS

The cumulative SEMS occlusion rate was 41.8% and 18.2% in the groups with and without UDCA, respectively (P = .0119). Median TRBO was significantly longer in the control group than in the UDCA group (528 vs 154 days, P = .0381). In the multivariate analysis, UDCA administration was identified as the independent risk factor for reducing TRBO (hazard ratio, 2.28; 95% confidence interval, 1.06-4.88; P = .0348). The overall early AE rate showed insignificant differences between groups.

CONCLUSIONS

Administering UDCA after SEMS placement was not efficacious for prolonging the TRBO in MDBO. Moreover, administering UDCA beyond a month might increase the risk of stent sludge occlusion. (Clinical trial registration number: UMIN000046862.).

Potential significance of uncovered self‐expandable metal stents for distal malignant biliary obstruction: A propensity score‐adjusted competing risk regression analysis

Objectives

Selection criteria for self‐expandable metal stents (SEMSs) with or without cover during palliative treatment of distal malignant biliary obstruction (DMBO) remain unclear. We evaluated factors associated with time to recurrent biliary obstruction (TRBO) in fully covered SEMSs (FCSEMSs) and uncovered SEMSs (UCSEMSs).

Methods

We retrospectively analyzed consecutive patients with DMBO who received a SEMS. TRBO was determined using the Kaplan–Meier analysis, and complications were compared between the FCSEMS and UCSEMS groups. After TRBO‐associated factors were extracted using multivariate competing‐risks regression (CRR), propensity score‐adjusted CRRs were performed to verify their robustness.

Results

There were 180 patients (66 FCSEMSs and 114 UCSEMSs) enrolled in this study. There was no significant difference between median TRBO in the FCSEMS and UCSEMS groups (275 vs. 255 days, p = 0.67). Complications were more frequent in the FCSEMS than UCSEMS group (21.2% vs. 8.8%; p = 0.023). Multivariate CRR for TRBO‐associated factors revealed that “pancreatic ductal carcinoma (PDAC) treated with UCSEMS” was the only independent predictor of TRBO (p = 0.03). Similarly, the propensity score‐adjusted CRRs showed no significant difference in TRBO in “FCSEMS” vs “UCSEMS” (p = 0.96); however, there was a significant difference in “PDAC using UCSEMS” vs “other” (p = 0.043). In the palliative care group including any DMBO without chemotherapy, the first quartile of the TRBO of UCSEMS was 100 days.

Conclusions

UCSEMSs are a possible option for both patients with DMBO arising from PDAC and for patients with any DMBO receiving palliative care who should avoid SEMS‐related complications.

ACG Clinical Guideline: Diagnosis and Management of Biliary Strictures

A biliary stricture is an abnormal narrowing in the ductal drainage system of the liver that can result in clinically and physiologically relevant obstruction to the flow of bile. The most common and ominous etiology is malignancy, underscoring the importance of a high index of suspicion in the evaluation of this condition. The goals of care in patients with a biliary stricture are confirming or excluding malignancy (diagnosis) and reestablishing flow of bile to the duodenum (drainage); the approach to diagnosis and drainage varies according to anatomic location (extrahepatic vs perihilar). For extrahepatic strictures, endoscopic ultrasound-guided tissue acquisition is highly accurate and has become the diagnostic mainstay. In contrast, the diagnosis of perihilar strictures remains a challenge. Similarly, the drainage of extrahepatic strictures tends to be more straightforward and safer and less controversial than that of perihilar strictures. Recent evidence has provided some clarity in multiple important areas pertaining to biliary strictures, whereas several remaining controversies require additional research. The goal of this guideline is to provide practicing clinicians with the most evidence-based guidance on the approach to patients with extrahepatic and perihilar strictures, focusing on diagnosis and drainage.

Endoscopic Ultrasound Guided Biliary Drainage in Malignant Distal Biliary Obstruction

Malignant biliary obstruction (MBO) is a challenging medical problem that often negatively impacts the patient's quality of life (QoL), postoperative complications, and survival rates. Endoscopic approaches to biliary drainage are generally performed by ERCP or, in selected cases, with a percutaneous transhepatic biliary drainage (PTBD). Recent advances in therapeutic endoscopic ultrasound (EUS) allow drainage where previous methods have failed. EUS has evolved from a purely diagnostic technique to one that allows a therapeutic approach in the event of ERCP failure in distal MBO. Moreover, the introduction of dedicated accessories and prostheses for EUS-guided transmural biliary drainage (EUS-BD) made these procedures more successful with regard to technical success, clinical outcomes and reduction of adverse events (AEs). Finally, lumen-apposing metal stents (LAMS) have improved the therapeutic role of the EUS. Subsequently, the electrocautery enhanced tip of the LAMS (EC-LAMS) allows a direct access of the delivery system to the target lumen, thereby simplifying and reducing the EUS-BD procedure time. EUS-BD using LAMS and EC-LAMS has proven effective and safe with a low rate of AEs. This review aims to evaluate biliary drainage techniques in malignant obstruction, focusing on the role of EUS biliary drainage by LAMS.

Covered versus uncovered double bare self-expandable metal stent for palliation of unresectable extrahepatic malignant biliary obstruction: a randomized controlled multicenter trial

BACKGROUND AND AIMS

In a recent randomized controlled trial, a double bare metal stent (DBS) showed better stent patency than single-layer metal stents. However, clear evidence comparing the efficacy of uncovered (UCDBS) and partially covered (PCDBS) DBSs for distal malignant biliary obstruction (MBO) is lacking. Therefore, we compared the clinical outcomes including stent patency of UCDBSs versus PCDBSs.

METHODS

A multicenter, randomized study was performed in patients with distal MBO. The primary endpoint was stent patency. Secondary endpoints were the proportion of patients with patent stents at 6 months, risk factors for stent dysfunction, overall survival, technical and clinical success rates of stent placement, and other adverse events (AEs).

RESULTS

Among 258 included patients, 130 were randomly assigned to the PCDBS group and 128 to the UCDBS group. The mean duration of stent patency of the PCDBS (421.2 days; 95% confidence interval [CI], 346.7-495.7) was longer than that of the UCDBS (377.4 days; 95% CI, 299.7-455.0), although total stent dysfunction and stent dysfunction within 6 months were not different between groups. Multivariate analysis indicated that chemotherapy after stent placement was a significant factor for overall survival (hazard ratio, .570; 95% CI, .408-.796) and had a marginal impact on stent patency (hazard ratio, 1.569; 95% CI, .923-2.667). There were no remarkable differences in AEs, including pancreatitis, cholecystitis, and stent migration, between the 2 groups.

CONCLUSIONS

The use of PCDBSs compared with UCDBSs in patients with distal MBO has unclear benefits regarding stent patency and overall survival, although PCDBSs have a lower rate of tumor ingrowth. (Clinical trial registration number: NCT02937246.).

Efficacy of a novel self-expandable metal stent with dumbbell-shaped flare ends for distal biliary obstruction due to unresectable pancreatic cancer

This study aimed to evaluate the efficacy of a novel fully covered self-expandable metal stent (SEMS) with dumbbell-shaped flare ends for the palliation of distal biliary obstruction (DBO) due to unresectable pancreatic cancer (UPC). Patients with DBO due to UPC who received the novel HILZO fully covered stent (HFS), the WALLFLEX partially covered stent (WPS) or fully covered stent (WFS) were analyzed. The incidence of recurrent biliary obstruction (RBO), time to RBO (TRBO), and the incidence of complications were compared among the three SEMS groups. Eighty-four patients (HFS, n = 36; WPS, n = 20; WFS, n = 28) were included. The incidence of RBO was low in the HFS group (versus the WPS and WFS group, p = 0.033 and 0.023, respectively). TRBO in the HFS group was longer than that in the WFS group (p = 0.049). Placement of the HFS was an independent factor for long TRBO in multivariable analysis (p = 0.040). The incidence of pancreatitis and cholecystitis in the HFS group was low (one for each). It is recommended to use the HFS for the palliation of DBO due to UPC from the viewpoint of the low incidence of RBO and complications.

Endoscopic palliation of malignant biliary obstruction

Malignant biliary obstruction often presents with challenges requiring the endoscopist to assess the location of the lesion, the staging of the disease, the eventual resectability and patient preferences in term of biliary decompression. This review will focus on the different modalities available in order to offer the most appropriate palliation, such as conventional endoscopic retrograde cholangiopancreatography, endoscopic ultrasound guided biliary drainage as well as ablative therapies including photodynamic therapy or radiofrequency ablation.

Covered versus uncovered metal stent for endoscopic drainage of a malignant distal biliary obstruction: Meta-analysis

OBJECTIVES

The role of a covered vs. an uncovered self-expandable metal stent (SEMS) for malignant distal biliary obstruction (MDBO) is not clear. This meta-analysis compared the efficacy of covered vs. uncovered SEMS for patients with MDBO after endoscopic insertion.

METHODS

A systematic meta-analysis of all relevant articles listed in PubMed, the Cochrane Library, and Google Scholar databases was performed. Fixed effects or random effects models were used to investigate pooled effects with 95% confidence intervals (CIs).

RESULTS

The meta-analysis included 2358 patients from 12 eligible studies. Time to recurrent biliary obstruction (RBO) was significantly longer for covered SEMS (mean difference, 45.51 days; 95% CI 11.79-79.24). Although there was no significant difference in the RBO rate, subgroup analysis in pancreatic cancer occupying more than 90% (PC) revealed that the RBO rates were significantly lower for covered SEMS (odds ratio [OR] 0.43, 95% CI 0.25-0.74). Stent migration, sludge formation, and overgrowth were significantly more common with a covered SEMS (OR 7.92, 95% CI 4.01-15.64; OR 3.25, 95% CI 1.89-5.59; OR 2.03, 95% CI 1.20-3.43, respectively). The rate of ingrowth was significantly lower for covered SEMS. There was no significant difference in total procedure-related adverse events between the two types of SEMS.

CONCLUSIONS

A covered SEMS is superior to an uncovered SEMS with respect to prevention of RBO in patients with MDBO, particularly those caused by PC.

Laser-cut-type versus braided-type covered self-expandable metallic stents for distal biliary obstruction caused by pancreatic carcinoma: a retrospective comparative cohort study

BACKGROUND/AIMS

Covered self-expandable metallic stents (CMSs) are widely used for malignant distal biliary obstructions (MDBOs) caused by pancreatic carcinoma. This study compared the efficacy and safety of the laser-cut-type and braided-type CMSs.

METHODS

To palliate MDBOs caused by pancreatic carcinoma, the laser-cut-type CMSs was used from April 2014 to March 2017, and the braided-type CMSs was used from April 2017 to March 2019. The tested self-expandable metallic stents were equipped with different anti-migration systems.

RESULTS

In total, 47 patients received CMSs for MDBOs (24 laser-cut type, 23 braided-type). The time to recurrent biliary obstruction (TRBO) was significantly longer in the braided-type CMSs (p=0.0008), and the median time to stent dysfunction or patient death was 141 and 265 days in the laser-cut-type CMSs and braided-type CMSs, respectively (p=0.0023). Stent migration was the major cause of stent dysfunction in both groups, which occurred in 37.5% of the laser-cut-type CMSs and 13.0% of the braidedtype CMSs. There were no differences in the survival duration between the groups.

CONCLUSION

The TRBO was significantly longer for the braided-type CMSs with an anti-migration system than for the laser-cuttype. Stent migration tended to be less frequent with the braided-type CMSs than with the laser-cut-type CMSs.

Endoscopic Reintervention for Recurrence of Malignant Biliary Obstruction: Developing the Best Strategy

Drainage therapy for malignant biliary obstruction (MBO) includes trans-papillary endoscopic retrograde biliary drainage (ERBD), percutaneous transhepatic biliary drainage (PTBD), and trans-gastrointestinal endoscopic ultrasound-guided biliary drainage (EUS-BD). With the development of chemotherapy, many MBO cases end up needing endoscopic reintervention (E-RI) for recurrent biliary obstruction. To achieve a successful E-RI, it is necessary to understand the various findings regarding E-RI in MBO cases reported to date. Therefore, in this review, we focus on E-RI for ERBD of distal MBO, ERBD of hilar MBO, and EUS-BD. To plan an appropriate E-RI strategy for biliary stent occlusion for MBO, the following must be considered on a case-by-case basis: the urgency of the drainage, the cause of the occlusion, the original route of drainage (PTBD/ERBD/EUS-BD), the initial stent used (plastic stent or self-expandable metallic stent), and in the case of self-expandable metallic stents, the type used (fully covered or uncovered). Regardless of the original method of stent placement, if the inflammation caused by obstructive cholangitis is severe and/or the patient is in shock, PTBD should be considered as the first choice. Finally, it is important to keep in mind that in many cases, performing E-RI will be difficult.

A Computational Framework Examining the Mechanical Behaviour of Bare and Polymer-Covered Self-Expanding Laser-Cut Stents

PURPOSE

Polymer covered stents have demonstrated promising clinical outcomes with improved patency rates compared to traditional bare-metal stents. However, little is known on the mechanical implication of stent covering. This study aims to provide insight into the role of a polymeric cover on the biomechanical performance of self-expanding laser-cut stents through a combined experimental-computational approach.

METHODS

Experimental bench top tests were conducted on bare and covered versions of a commercial stent to evaluate the radial, axial and bending response. In parallel, a computational framework with a novel covering strategy was developed that accurately predicts stent mechanical performance. Different stent geometries and polymer materials were also considered to further improve understanding on covered stent mechanics.

RESULTS

Results show that stent covering causes increased initial axial stiffness and up to 60% greater radial resistive force at small crimp diameters as the cover folds and self-contacts. The incorporation of a cover allows stent designs without interconnecting struts, thereby providing improved flexibility without compromising radial force. It was also shown that use of a stiffer PET polymeric covering material caused significant alterations to the radial and axial response, with the initial axial stiffness increasing six-fold and the maximum radial resistive force increasing four-fold compared to a PTFE-PU covered stent.

CONCLUSION

This study demonstrates that stent covering has a substantial effect on the overall stent mechanical performance and highlights the importance of considering the mechanical properties of the combined cover and stent.

Fully covered metal biliary stents: A review of the literature

Fully covered self-expandable metal stents (FCSEMS) represent the latest advancement of metal biliary stents used to endoscopically treat a variety of obstructive biliary pathology. A large stent diameter and synthetic covering over the tubular mesh prolong stent patency and reduce risk for tissue hyperplasia and tumor ingrowth. Additionally, FCSEMS can be easily removed. All these features address issues faced by plastic and uncovered metal stents. The purpose of this paper is to comprehensively review the application of FCSEMS in benign and malignant biliary strictures, biliary leak, and post-sphincterotomy bleeding.

Uncovered versus covered metallic stents for the management of unresectable malignant distal biliary obstruction: a randomized multicenter trial

OBJECTIVE

The treatment result of the uncovered metallic stent (uncovered MS) and covered metallic stent (covered MS) for unresectable malignant distal biliary obstruction is controversial. This time, we conducted this study to compare the efficacies and complication rates of uncovered MS and covered MS in unresectable malignant distal biliary obstructions at a prospective randomized multicenter trial.

MATERIALS AND METHODS

From April 2014 to September 2018, patients with unresectable malignant distal biliary obstruction were randomly assigned to 2 groups: the uncovered MS group and the covered MS group.

RESULTS

92 treatment results patients were discussed. 48 patients were assigned to the uncovered MS group and 44 cases were assigned to the covered MS group. Both groups showed a drainage effect. No significant difference was found in the drainage effect between the 2 groups. The number of stent occlusion was significantly greater (p = .0467) in uncovered MS (43.8%) comparing with those in covered MS (22.7%). As the cause of stent occlusion, tumor ingrowth was significantly greater (p < .001) in the uncovered MS group (35.4%) than in the covered MS group (2.3%). The median stent patency period was significantly longer (p = .0112) in the covered MS group (455 days) than that of the uncovered MS group (301 days). A significant difference in the median survival period was not found between the 2 groups.

CONCLUSIONS

Covered MS showed the possibility of extending the stent patency period by suppressing tumor ingrowth more than uncovered MS does. The UMIN Clinical Trial Registry number is UMIN000015093.

Stent placement combined with intraluminal radiofrequency ablation and hepatic arterial infusion chemotherapy for advanced biliary tract cancers with biliary obstruction: a multicentre, retrospective, controlled study

OBJECTIVE

To evaluate the efficacy and safety of stent placement combined with intraluminal radiofrequency ablation (intra-RFA) and hepatic arterial infusion chemotherapy (HAIC) for patients with advanced biliary tract cancers (Ad-BTCs) and biliary obstruction (BO).

METHODS

We retrospectively reviewed data for patients with Ad-BTCs and BO who underwent stent placement with or without intra-RFA and HAIC in three centres between November 2013 and November 2018. The stent patency time (SPT), overall survival (OS), and adverse events (AEs) were analysed.

RESULTS

Of the 135 enrolled patients, 64 underwent stent placement combined with intra-RFA and HAIC, while 71 underwent only stent placement. The median SPT was significantly longer in the combination group (8.2 months, 95% confidence interval [CI]: 7.1-9.3) than in the control group (4.3 months, 95% CI: 3.6-5.0; p < 0.001). A similar result was observed for OS (combination: 13.2 months, 95% CI: 11.1-16.5; control: 8.5 months, 95% CI: 7.6-9.6; p < 0.001). The incidence of AEs related to biliary tract operation was not significantly different between the two groups (p > 0.05). The most common AE and serious AE related to HAIC were alanine aminotransferase elevation (24/64; 37.5%) and thrombocytopenia (8/64; 12.5%), respectively. All AEs were tolerable, and there was no death from AEs.

CONCLUSIONS

Stent placement combined with intra-RFA and HAIC may be a safe, potential treatment strategy for patients with Ad-BTCs and BO.

KEY POINTS

• Advanced biliary cancers (Ad-BTCs) with biliary obstruction (BO) can rapidly result in liver failure and cachexia with an extremely poor prognosis. • Stent placement combined with intraluminal radiofrequency ablation and hepatic arterial infusion chemotherapy may be safe and effective for patients with Ad-BTCs and BO. • The long-term efficacy and safety of the combined treatment is promising.

Endoscopic Stenting for Malignant Biliary Obstruction: Results of a Nationwide Experience

Background/Aims

Many unanswered questions remain about the treatment of malignant hilar obstruction. We investigated endoscopic stenting for malignant biliary strictures, as reported in a nationwide registry.

Methods

All endoscopic retrograde cholangiopancreatography (ERCP) procedures entered in the Swedish Registry of Gallstone Surgery and ERCP from January 2010 to December 2017 in which stenting was performed for malignant biliary stricture management were included in this study. Patency was estimated by determining the time to reintervention.

Results

Endoscopic stenting was performed for malignant stricture management in 4623 ERCP procedures, of which 1364 (29.5%) were performed for hilar strictures. Of the hilar strictures, 320 (23.5%) were intrahepatic strictures (Bismuth-Corlette III-IV). Adverse events were more common after hilar stenting than after distal stenting (17.2% vs. 12.0%, p<0.0001). The 6-month reintervention rate was 73.4% after hilar stenting compared with 55.9% after distal stenting (p<0.0001). The 6-month reintervention rates for Bismuth-Corlette types I, II, IIIa, IIIb, and IV were 70.4%, 75.6%, 90.0%, 87.5%, and 85.7%, respectively. In multivariate analysis, the risk for reintervention was three times higher after hilar stenting than after distal stenting (hazard ratio 3.47, 95% confidence interval 2.01-6.00, p<0.001).

Conclusions

This study with a relatively large patient cohort undergoing endoscopic stenting confirms that stenting for malignant hilar obstruction has more adverse events and lower patency than stenting for distal malignant obstruction.

Endoscopic management of ampullary tumors: European Society of Gastrointestinal Endoscopy (ESGE) Guideline

1: ESGE recommends against diagnostic/therapeutic papillectomy when adenoma is not proven.Strong recommendation, low quality evidence. 2: ESGE recommends endoscopic ultrasound and abdominal magnetic resonance cholangiopancreatography (MRCP) for staging of ampullary tumors.Strong recommendation, low quality evidence. 3: ESGE recommends endoscopic papillectomy in patients with ampullary adenoma without intraductal extension, because of good results regarding outcome (technical and clinical success, morbidity, and recurrence).Strong recommendation, moderate quality evidence. 4: ESGE recommends en bloc resection of ampullary adenomas up to 20-30 mm in diameter to achieve R0 resection, for optimizing the complete resection rate, providing optimal histopathology, and reduction of the recurrence rate after endoscopic papillectomy.Strong recommendation, low quality evidence. 5: ESGE suggests considering surgical treatment of ampullary adenomas when endoscopic resection is not feasible for technical reasons (e. g. diverticulum, size > 4 cm), and in the case of intraductal involvement (of > 20 mm). Surveillance thereafter is still mandatory.Weak recommendation, low quality evidence. 6: ESGE recommends direct snare resection without submucosal injection for endoscopic papillectomy.Strong recommendation, moderate quality evidence. 7: ESGE recommends prophylactic pancreatic duct stenting to reduce the risk of pancreatitis after endoscopic papillectomy.Strong recommendation, moderate quality evidence. 8: ESGE recommends long-term monitoring of patients after endoscopic papillectomy or surgical ampullectomy, based on duodenoscopy with biopsies of the scar and of any abnormal area, within the first 3 months, at 6 and 12 months, and thereafter yearly for at least 5 years.Strong recommendation, low quality evidence.

Lumen-apposing metal stent through the meshes of duodenal metal stents for palliation of malignant jaundice

Background and study aims  Endoscopic retrograde cholangiopancreatography (ERCP) is the gold standard procedure for malignant jaundice palliation; however, it can be challenging when a duodenal self-expandable metal stent (SEMS) is already in place. Patients and methods  The primary aim of our study was to evaluate the technical feasibility of the placement of a lumen apposing metal stent (LAMS) through the mesh (TTM) of duodenal stents. The secondary aims were to evaluate clinical outcomes and adverse events (AEs) related to the procedures. Results  Data from 23 patients (11 F and 12 M; mean age: 69.5 ± 11 years old) were collected. In 17 patients (73.9 %) TTM LAMS placement was performed as first intention, while in six patients (26.1 %) it was performed after a failed ERCP. Thirteen patients (56.5 %) underwent the procedure due to advanced pancreatic head neoplasia. One technical failure was experienced (4.3 %). The TTM LAMS placement led to a significant decrease in the serum levels of bilirubin, ALP, GGT, WBC and CRP. No cases of duodenal SEMS occlusion occurred and no other AEs were observed during the follow-up. Conclusions  Concomitant malignant duodenal and biliary obstruction is a challenging condition. Palliation of jaundice using TTM LAMS in patients already treated with duodenal stent is associated to promising technical and clinical outcomes.

Antireflux metal stent for biliary obstruction: Any benefits?

Endoscopic retrograde cholangiopancreatography with stent placement has been utilized as standard palliative management of distal malignant biliary obstruction (MBO). Compared to plastic stents, metal stents can provide longer-term relief of symptoms. When a large-bore metal stent is placed across the ampulla, patients are predisposed to the risk of cholangitis or stent dysfunction due to reflux of duodenal contents. To mitigate the risk of adverse events associated with the duodenobiliary reflux, efforts have been directed to development of antireflux metal stents (ARMSs). The antireflux property has been introduced through adding of an antireflux valve to the duodenal stent end. Evidence from clinical studies indicates that ARMSs may not only reduce the risk of ascending cholangitis during follow-up but also prolong stent patency time. However, the results of clinical studies testing ARMSs are inconsistent owing to heterogeneous designs of antireflux valves and stent bodies. Metal stents are increasingly indicated for benign biliary strictures and MBO in the setting of neoadjuvant chemotherapy, and therefore, research is warranted to evaluate ARMSs for those indications. Given that endoscopic ultrasound (EUS)-guided transmural biliary drainage has gained popularity, the optimal timing of placing an ARMS in relation to EUS-guided and percutaneous drainage should be investigated. Development and evaluation of ARMSs require an integrative approach utilizing phantom and animal models, measurements of stent mechanical properties, and in vivo functional study after stent placement. In this review article, we summarize updated evidence on ARMSs for MBO and discuss issues that should be addressed in future studies.

Comparing the 14-mm uncovered and 10-mm covered metal stents in patients with distal biliary obstruction caused by unresectable pancreatic cancer: a multicenter retrospective study

BACKGROUND

Endoscopic biliary drainage using metal stent (MSs) is an established palliative treatment for patients with unresectable malignant distal biliary obstruction (MDBO). However, a major drawback of MS is recurrent biliary obstruction (RBO). Uncovered MSs with a diameter of 14 mm (UMS-14) were developed to overcome this. We aimed to compare the clinical outcomes of UMS-14 with those of conventional covered MSs having a diameter of 10 mm (CMS-10).

METHODS

Consecutive patients with MDBO caused by unresectable pancreatic cancer, who underwent UMS-14 or CMS-10 placement at two tertiary-care centers, were retrospectively examined according to the Tokyo Criteria 2014.

RESULTS

Two hundred and thirty-eight patients who underwent UMS-14 (the UMS-14 group, n = 80) or CMS-10 (the CMS-10 group, n = 158) over a 62-month period were included. The technical and clinical success rates were similar between the two groups. RBO occurred in 20 (25%) and 59 (37%) patients of the UMS-14 and CMS-10 groups, respectively (p = 0.06). Median time till RBO was significantly longer in the UMS-14 group than in the CMS-10 group (not reached vs. 290 days, p = 0.04). Multivariate analysis revealed that CMS-10 placement was an independent risk factor for RBO (hazard ratio: 1.66, 95% confidence interval: 1.00-2.76). The incidence of early complications, including pancreatitis, and the overall survival (UMS-14 vs. CMS-10: 169 vs. 167 days, p = 0.83) were comparable between the two groups.

CONCLUSIONS

UMS-14 stents were safe and effective for treating patients with MDBO secondary to unresectable pancreatic cancer. The insertion of UMS-14 is recommended, because it is less likely to get occluded as compared to CMS-10.

Comparative Efficacy of Various Stents for Palliation in Patients with Malignant Extrahepatic Biliary Obstruction: A Systematic Review and Network Meta-Analysis

Although many studies have investigated the efficacy of stent placement for patients with malignant extrahepatic biliary obstruction, the clinical outcomes and adverse events of biliary stenting have not been comprehensively evaluated. We searched all relevant randomized-controlled trials that evaluated the comparative efficacy of biliary stents, including the plastic stents, uncovered self-expandable metal stents (SEMSs), and covered SEMSs in patients with malignant extrahepatic biliary obstructions. Twenty-one studies with 2326 patients were included. Both uncovered and covered SEMSs had a lower risk of recurrent biliary obstruction (RBO) compared to plastic stents (risk ratio (RR) (95% confidence interval [CI]): uncovered vs. plastic, 0.46 (0.35–0.62); covered vs. plastic, 0.46 (0.34–0.62)). A comparison of the groups using SEMSs revealed that tumor ingrowth was common in the uncovered SEMS group, while stent migration, tumor overgrowth, and occlusion by sludge were common in the covered SEMS group; however, the overall risk of RBO did not differ between these groups (RR (95% CI): uncovered vs. covered: 1.02 (0.80–1.30)). Although the main causes of RBO vary across stents, RBO risk was similar between uncovered and covered SEMS groups. Both SEMSs have superior efficacy in terms of RBO compared to plastic stents.

Advances in stent therapy for malignant biliary obstruction

Malignant biliary obstruction (MBO), result of pancreatobiliary diseases is a challenging condition. Most patients with MBO are inoperable at the time of diagnosis, and the disease is poorly controlled using external-beam radiotherapy and chemotherapy. Biliary stent therapy emerged as a promising strategy for alleviating MBO and prolonging life. However, physicians find it difficult to determine the optimal type of biliary stent for the palliation of MBO. Here, we review the safety and efficacy of available biliary stents, used alone or in combination with brachytherapy, photodynamic therapy and advanced chemotherapeutics, in patients with pancreatobiliary malignancies and put forward countermeasures involving stent obstruction. Furthermore, 3D-printing stents and nanoparticle-loaded stents have broad application prospects for fabricating tailor-made biliary stents.

Utility and Safety of a Novel Fully Covered Metal Stent in Unresectable Distal Malignant Biliary Obstruction

BACKGROUND

Self-expandable metal stents (SEMSs) are widely used in patients with distal malignant biliary obstruction. A SEMS that can avoid occlusion as much as possible is desirable.

AIMS

The aim of this multicenter single-arm prospective study was to assess the clinical effectiveness and safety of a novel fully covered braided SEMS.

METHODS

We enrolled consecutive patients with distal malignant biliary obstruction between February 2016 and November 2017 at ten tertiary-care medical centers.

RESULTS

We included 79 patients with a median age of 76 years; 47 (59.5%) patients were men. The technical and clinical success rate was 98.7% and 93.6%, respectively. Recurrent biliary obstruction occurred in 14 patients (17.9%); stent ingrowth, overgrowth, migration, and other occurred in five (6.4%), four (5.1%), four (5.1%), and one (1.3%) patients, respectively. All reinterventions in patients with recurrent biliary obstruction were successful via the transpapillary approach. Adverse events occurred in 15 patients (19.2%); cholangitis, pancreatitis, and others occurred in ten (12.8%), three (3.8%), and two (2.6%) patients, respectively. The stent patency probability at 6 months was 48.5%. Median time to stent patency was 171 days, median time to recurrent biliary obstruction was 536 days, and median survival time was 195 days.

CONCLUSIONS

We confirmed the utility and safety of a novel fully covered braided SEMS with low axial force and high radial force in patients with malignance biliary obstruction. This novel SEMS is recommended in patients with distal malignant biliary obstruction.

Folfirinox chemotherapy prolongs stent patency in patients with malignant biliary obstruction due to unresectable pancreatic cancer

BACKGROUND

Stent insertion for biliary decompression to relieve jaundice and subsequent biliary infection is necessary for patients with biliary obstruction caused by pancreatic cancer, and it is important to keep the stent patent as long as possible. However, few studies have compared stent patency in terms of chemotherapy in patients with pancreatic cancer. This study aimed to evaluate the differences in stent patency in terms of recently evolving chemotherapy.

METHODS

Between January 2015 and May 2017, 161 patients with pancreatic cancer who had undergone biliary stent insertion with a metal stent were retrospectively analyzed. The relationship between chemotherapy and stent patency was assessed. Additionally, overall survival according to the treatment, risk factors for stent patency, and long-term adverse events were evaluated.

RESULTS

Median stent patency was 42 days for patients with the best supportive care and 217 days for patients with chemotherapy (conventional gemcitabine-based chemotherapy and folfirinox) (P < 0.001). Furthermore, the folfirinox group showed the longest median stent patency and overall survival, with 283 days and 466 days, respectively (P < 0.001) despite higher adverse events rate. Patients who underwent folfirinox chemotherapy after stent insertion had better stent patency in multivariate analysis (HR = 0.26; 95% CI: 0.12-0.60; P = 0.001).

CONCLUSIONS

Compared with patients who received best supportive care only, patients who underwent chemotherapy after stent insertion had better stent patency. More prolonged stent patency can be expected for patients with folfirinox than conventional gemcitabine-based chemotherapy.

Endoscopic retrograde cholangiopancreatography guided interventions in the management of pancreatic cancer

Pancreatic cancer is the leading cause of cancer-related morbidity and mortality with an overall five-year survival of less than 9% in the United States. At presentation, the majority of patients have painless jaundice, pruritis, and malaise, a triad that develops secondary to obstruction, which often occurs late in the course of the disease process. The technical advancements in radiological imaging and endoscopic interventions have played a crucial role in the diagnosis, staging, and management of patients with pancreatic cancer. Endoscopic retrograde cholangiopancreatography (ERCP)-guided diagnosis (with brush cytology, serial pancreatic juice aspiration cytologic examination technique, or biliary biopsy) and therapeutic interventions such as pancreatobiliary decompression, intraductal and relief of gastric outlet obstruction play a pivotal role in the management of advanced pancreatic cancer and are increasingly used due to improved morbidity and complication rates compared to surgical management. In this review, we highlight various ERCP-guided diagnostic and therapeutic interventions for the management of pancreatic cancer.

Endoscopic drainage in patients with malignant extrahepatic biliary obstruction: when and how

The question of when and how to drain a malignant biliary obstruction (MBO), both intrinsic or extrinsic, remains a controversial point among endoscopists. An important factor that influences the decision to drain an MBO or not is if the patient is a surgical candidate or not and, in the former case, if the patients must undergo neoadiuvant chemotherapy or not. Other questions arising during biliary drainage in MBO patients is which type of stent should be chosen, plastic or metal, and if endoscopic biliary sphincterotomy must be performed or not when a stent is placed. The present review attempts to answer these questions and summarizes the optimal approach toward patients with MBO based on the available evidence.

Optimization of biliary drainage in inoperable distal malignant strictures

BACKGROUND

Given most patients with distal malignant biliary obstruction present in the non-resectable stage, palliative endoscopic biliary drainage with fully covered metal stent (FCMS) or uncovered metal stent (UCMS) is the only available measure to improve patients’ quality of life. Half covered metal stent (HCMS) has been recently introduced commercially. The adverse effects and stent function between FCMS and UCMS have been extensively discussed.

AIM

To study the duration of stent patency of HCMS and compare it with FCMS and UCMS to optimize biliary drainage in inoperable patients with distal malignant obstruction. Secondary aims in our study included evaluation of patients’ survival and the rates of adverse events for each type of stent.

METHODS

We studied 210 patients and randomized them into three equal groups; HCMS, FCMS and UCMS were inserted endoscopically.

RESULTS

Stent occlusion occurred in (18.6%, 17.1% and 15.7% in HCMS, FCMS and UCMS groups, respectively, P = 0.9). Stent migration occurred only in patients with FCMS (8.6% of patients). Cholangitis and cholecystitis occurred in 11.4% and 5.7% of patients, respectively, in FCMS. Tumor growth occurred only in 10 cases among patients with UCMS after a median of 140 d, sludge occurred in nine, seven and one patients in HCMS, FCMS and UCMS, respectively (P = 0.04).

CONCLUSION

Given the prolonged stent functioning time, the use of HCMS is preferred over the use of UCMS and FCMS for optimizing biliary drainage in patients with distal malignant biliary obstruction.

Usefulness of half-covered metallic stent placement in preventing acute cholecystitis complication in pancreatic cancer-induced distal biliary stricture

Background and Aim

A self-expandable metallic stent (SEMS) is commonly used for biliary stricture caused by pancreatic cancer. Covered SEMS may obstruct the cystic duct, causing acute cholecystitis. This study aimed to determine the outcomes of using a half-covered SEMS with an offset covered portion for preventing cystic duct obstruction.

Methods

Among 80 patients with half-covered SEMS placement for the treatment of pancreatic cancer-induced distal biliary stricture, 74 were followed up. The half-covered SEMS has a total length of 6 or 7 cm, and the offset covered part was 0.5-4.5 or 0.5-5.5 cm, respectively. Intraductal ultrasonography (IDUS) and endoscopic nasobiliary drainage (ENBD) were performed during the initial endoscopic retrograde cholangiopancreatography (ERCP). IDUS findings and ENBD tube cholangiogram confirmed the cystic duct confluence. SEMS placement was performed on the second ERCP or several weeks after the initial tube stent placement.

Results

Half-covered SEMS placement was successful in all patients. However, four (5.4%) patients exhibited early complications, including acute cholecystitis in one patient and stent displacement in another. Over 30 days, cholangitis, tumor growth, and stent displacement occurred in nine (11.3%), five (6.3%), and two (2.5%) patients, respectively. The median stent patency was 71.1 weeks, and the median overall survival in patients with and without chemotherapy was 31.8 and 12.2 weeks, respectively.

Conclusions

With confirmation of the cystic duct confluence, half-covered SEMS placement may become a treatment option for distal biliary stricture caused by pancreatic cancer to prevent acute cholecystitis. Half-covered SEMS patency was comparable with that of covered SEMS.

Feasibility and efficacy evaluation of metallic biliary stents eluting gemcitabine and cisplatin for extrahepatic cholangiocarcinoma

BACKGROUND

Effective endoscopic management is fundamental for the treatment of extrahepatic cholangiocarcinoma (ECC). However, current biliary stents that are widely used in clinical practice showed no antitumor effect. Drug-eluting stents (DESs) may achieve a combination of local chemotherapy and biliary drainage to prolong stent patency and improve prognosis.

AIM

To develop novel DESs coated with gemcitabine (GEM) and cisplatin (CIS)-coloaded nanofilms that can maintain the continuous and long-term release of antitumor agents in the bile duct to inhibit tumor growth and reduce systemic toxicity.

METHODS

Stents coated with different drug-eluting components were prepared by the mixed electrospinning method, with poly-L-lactide-caprolactone (PLCL) as the drug-loaded nanofiber membrane and GEM and/or CIS as the antitumor agents. Four different DESs were manufactured with four drug-loading ratios (5%, 10%, 15%, and 20%), including bare-loaded (PLCL-0), single-drug-loaded (PLCL-GEM and PLCL-CIS), and dual-drug-loaded (PLCL-GC) stents. The drug release property, antitumor activity, and biocompatibility were evaluated in vitro and in vivo to confirm the feasibility and efficacy of this novel DES for ECC.

RESULTS

The in vitro drug release study showed the stable, continuous release of both GEM and CIS, which was sustained for over 30 d without an obvious initial burst, and a higher drug-loaded content induced a lower release rate. The drug-loading ratio of 10% was used for further experiments due to its ideal inhibitory efficiency and relatively low toxicity. All drug-loaded nanofilms effectively inhibited the growth of EGI-1 cells in vitro and the tumor xenografts of nude mice in vivo; in addition, the dual-loaded nanofilm (PLCL-GC) had a significantly better effect than the single-drug-loaded nanofilms (P < 0.05). No significant differences in the serological analysis (P > 0.05) or histopathological changes were observed between the single-loaded and drug-loaded nanofilms after stent placement in the normal porcine biliary tract.

CONCLUSION

This novel PLCL-GEM and CIS-eluting stent maintains continuous, stable drug release locally and inhibits tumor growth effectively in vitro and in vivo. It can also be used safely in normal porcine bile ducts. We anticipate that it might be considered an alternative strategy for the palliative therapy of ECC patients.

Endoscopic Management of Malignant Biliary Stricture

A biliary stricture is an area of narrowing in the extrahepatic or intrahepatic biliary system. The majority of biliary strictures are caused by malignancies, particularly cholangiocarcinoma and pancreatic adenocarcinoma. Most malignant biliary strictures are unresectable at diagnosis. Treatment of these diseases historically required surgical procedures, however, the development of endoscopic techniques has provided alternative minimally invasive treatment options to improve patient quality of life and survival with unresectable disease. While endoscopic retrograde cholangiopancreatography with stent placement has been the cornerstone of biliary drainage for decades, cutting edge endoscopic developments, including radiofrequency ablation and endoscopic ultrasound-guided biliary drainage, offer new therapy options to patients that historically have a poor quality of life and a grim prognosis. In this review, we explore the endoscopic techniques that have contributed to revolutionary advancements in the endoscopic management of malignant biliary strictures.