Partially covered versus uncovered self-expandable nitinol stents with anti-migration properties for the palliation of malignant distal biliary obstruction: A randomized controlled trial

Selective Tumor Inhibition Effect of Drug-Free Layered Double Hydroxide-Based Films via Responding to Acidic Microenvironment

Nickel-titanium alloy stents are widely used in the interventional treatment of various malignant tumors, and it is important to develop nickel-titanium alloy stents with selective cancer-inhibiting and antibacterial functions to avoid malignant obstruction caused by tumor invasion and bacterial colonization. In this work, an acid-responsive layered double hydroxide (LDH) film was constructed on the surface of a nickel-titanium alloy by hydrothermal treatment. The release of nickel ions from the film in the acidic tumor microenvironment induces an intracellular oxidative stress response that leads to cell death. In addition, the specific surface area of LDH nanosheets could be further regulated by heat treatment to modulate the release of nickel ions in the acidic microenvironment, allowing the antitumor effect to be further enhanced. This acid-responsive LDH film also shows a good antibacterial effect against S. aureus and E. coli. Besides, the LDH film prepared without the introduction of additional elements maintains low toxicity to normal cells in a normal physiological environment. This work offers some guidance for the design of a practical nickel-titanium alloy stent for the interventional treatment of tumors.

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.

A novel fully covered metal stent for unresectable malignant distal biliary obstruction: results of a multicenter prospective study

BACKGROUND/AIMS

Endoscopic self-expandable metal stent (SEMS) placement is currently the standard technique for treating unresectable malignant distal biliary obstructions (MDBO). Therefore, covered SEMS with longer stent patency and fewer migrations are required. This study aimed to assess the clinical performance of a novel, fully covered SEMS for unresectable MDBO.

METHODS

This was a multicenter single-arm prospective study. The primary outcome was a non-obstruction rate at 6 months. The secondary outcomes were overall survival (OS), recurrent biliary obstruction (RBO), time to RBO (TRBO), technical and clinical success, and adverse events.

RESULTS

A total of 73 patients were enrolled in this study. The non-obstruction rate at 6 months was 61%. The median OS and TRBO were 233 and 216 days, respectively. The technical and clinical success rates were 100% and 97%, respectively. Furthermore, the rate of occurrence of RBO and adverse events was 49% and 21%, respectively. The length of bile duct stenosis (<2.2 cm) was the only significant risk factor for stent migration.

CONCLUSIONS

The non-obstruction rate of a novel fully covered SEMS for MDBO is comparable to that reported earlier but shorter than expected. Short bile duct stenosis is a significant risk factor for stent migration.

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.).

Endoscopic retrograde stent drainage therapies for malignant biliary obstruction: the distal opening of stent location above or across the duodenal papilla? A systematic review and meta-analysis

OBJECTIVE

To systematically evaluate the efficacy and safety of the method of placing the distal stent opening above the duodenal papilla (hereinafter referred to Above method) for endoscopic retrograde stent internal drainage in MBO patients.

METHODS

PubMed, Embase, Web of science and Cochrane databases were searched to identify clinical studies comparing the stent distal opening mounted above the papilla and across the papilla (hereinafter referred to Across method), Comparison indicators included stent patency, stent occlusion rate, clinical success rate, overall complication rate, postoperative cholangitis rate, and overall survival. Revman5.4 software was used for meta-analysis, funnel plot and publication bias and Egger's test were completed by Stata14.0 software.

RESULTS

A total of 11 clinical studies (8 case-control studies, 3 RCT studies) were included, with a total of 751 patients (318 cases in the Above group and 433 cases Across group). The overall patency of Above method was longer than that of Across method (HR = 0.60, 95%CI [0.46-0.78], p < 0.001). Subgroup analysis showed statistical difference using plastic stent (HR = 0.49, 95%CI [0.33,0.73], p < 0.001). Inversely, there didn't exist significant difference in which metal stent were adopted (HR= 0.74, 95%CI [0.46,1.18], p = 0.21). Similarly, there also without statistical difference between patients with plastic stent placed above the papilla and metal stent mounted Across the papilla (HR = 0.73, 95%CI [0.15,3.65], p = 0.70). Moreover, the overall complication rate of the Above method was lower than that of the Across method (OR = 0.48,95%CI [0.30,0.75], p = 0.002). On the contrary, the differences of stent occlusion rate (OR = 0.86,95%CI [0.51,1.44], p = 0.56), overall survival (HR = 0.90, 95%CI [0.71,1.13]), p = 0.36), the clinical success rate (OR = 1.30, 95%CI [0.52,3.24], p = 0.57) and postoperative cholangitis rats (OR = 0.73, 95%CI [0.34,1.56], p = 0.41) were not statistically significant.

CONCLUSIONS

The distal opening of the stent can be placed above the duodenal main papilla for eligible MBO patients who receiving endoscopic retrograde stent drainage treatment, which can effectively prolong the patency duration when plastic stent is used, and reduce the overall risk of complications.

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.

Efficacy of Fully Covered Self-Expandable Metal Stents for Distal Biliary Obstruction Caused by Pancreatic Ductal Adenocarcinoma: Primary Metal Stent vs. Metal Stent following Plastic Stent

Fully covered self-expandable metallic stents (FCSEMSs) are inserted in patients with unresectable pancreatic ductal adenocarcinoma (PDAC) to resolve malignant distal bile duct obstructions. Some patients receive FCSEMSs during primary endoscopic retrograde cholangiopancreatography (ERCP), and others receive FCSEMSs during a later session, after the placement of a plastic stent. We aimed to evaluate the efficacy of FCSEMSs for primary use or following plastic stent placement. A total of 159 patients with pancreatic adenocarcinoma (m:f, 102:57) who had achieved clinical success underwent ERCP with the placement of FCSEMSs for palliation of obstructive jaundice. One-hundred and three patients had received FCSEMSs in a first ERCP, and 56 had received FCSEMSs after prior plastic stenting. Twenty-two patients in the primary metal stent group and 18 in the prior plastic stent group had recurrent biliary obstruction (RBO). The RBO rates and self-expandable metal stent patency duration did not differ between the two groups. An FCSEMS longer than 6 cm was identified as a risk factor for RBO in patients with PDAC. Thus, choosing an appropriate FCSEMS length is an important factor in preventing FCSEMS dysfunction in patients with PDAC with malignant distal bile-duct obstruction.

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.

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.).

Feasibility and safety of trans-biliary cryoablation: Preclinical evaluation of a novel flexible cryoprobe

Cryoablation, as a well-characterized technology, has multifarious clinical applications in solid malignancy. However, trans-biliary cryoablation for malignant biliary obstruction has not been reported yet. Thus, this study aimed to determine the efficacy and safety of trans-biliary cryoablation with a novel CO₂ gas-based flexible cryoprobe in standardized preclinical settings. For fresh porcine liver ex vivo, the freezing efficacy of cryoablation was evaluated by using fresh porcine liver. The real-time CO2 flow rate, freezing temperature and freezing range were examined and the frozen appearance was visualized. In vivo study, acute and chronical effects were investigated by using the models of canine bile duct. Histopathology and laboratory examination were performed. The lowest temperature that the electrode could deliver to the tissue was -60.7 °C. At 60s after freezing, the tissue temperature dropped to -22.6 °C and -4.3 °C at 0.1 and 0.2 cm from the electrode center, respectively. The frozen size was greater in liver tissue ex vivo than that in bile duct tissue in vivo. No biliary hemorrhage, perforation, stricture, obstruction, and adjacent organ injury were observed. With histopathologic examination, acute intercellular vacuoles were observed in the lamina propria adjacent to the lumen. Chronic changes, including uneven coagulative necrosis, fibro-proliferation, inflammatory infiltration and connective tissue thickening were observed in the lamina propria of the all biliary samples. The results demonstrated CO₂ gas-based trans-biliary cryoablation is safe and efficacious. These findings may provide a potential new modality for primary malignant biliary obstruction and malignant obstruction within a biliary stent and contribute to cryoablation of clinical practice.

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 Management of Pancreatobiliary Malignancies

Pancreatobiliary malignancies have poor prognosis, and many patients are inoperable at the time of diagnosis. When surgical resection is impossible, systemic chemotherapy or radiotherapy is traditionally conducted with trial of immunotherapy or gene therapy lately. With the rapid development of endoscopic instruments and accessories in recent years, not only endoscopic early detection, characterization, and staging but also endoscopic palliative management of the pancreatobiliary malignancies is expanding the horizons. Endoscopic management is often preferred due to similar efficacy to surgical management with less morbidity. Here, we review the methodology and treatment outcome of various endoscopic management strategies in pancreatobiliary malignancies including endoscopic complication management, local palliative therapy, endoscopy-assisted therapy, and pain control utilizing endoscopic retrograde cholangiopancreatography or endoscopic ultrasound.

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.

Prevention of pancreatitis after stent implantation for distal malignant biliary strictures: systematic review and meta-analysis

INTRODUCTION

Biliary stent placement remains a palliative treatment for patients with unresectable distal malignant biliary strictures (DMBS). The incidence of post-ERCP-pancreatitis (PEP) significantly increases in patients receiving fully covered self-expandable metal stents (FCSEMS) who undergo endoscopic retrograde cholangiopancreatography (ERCP).

AREAS COVERED

This review provides an overview of prevention of PEP after stent implantation for DMBSs. The following operational variables were evaluated: (1) stent type (plastic or metal stent); (2) stent location (above or across the sphincter of Oddi); (3) prophylactic pancreatic duct stent placement; (4) endoscopic sphincterotomy (EST). PubMed, EMBASE, and Cochrane database were searched to identify eligible studies up to October 2021. The odds ratio (OR) with 95% confidence intervals (CI) were pooled using fixed- or random- effects models.

EXPERT OPINION

1. PEP occurs more frequently in DMBS patients with self-expandable metal stents (SEMS) compared to that plastic stent (PS). 2. The PEP incidence is higher in covered stents than that in uncovered self-expandable metal stents (USEMS), but not significantly. 3. PEP incidence increases in patients receiving transpapillary FCSEMS placement, particularly when there is an absence of pancreatic duct dilation, and prophylactic pancreatic stenting is recommended for these patients. 4. Limited studies with small sample indicate that there is no significant difference in PEP incidence between transpapillary and suprapapillary stents placement for DMBS. 5. Limited studies indicate that EST does not significantly affect the incidence of pancreatitis in DMBS patients.

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.

Efficacy of an internal anchoring plastic stent to prevent migration of a fully covered metal stent in malignant distal biliary strictures: a randomized controlled study

BACKGROUND

Two types of self-expandable metal stents (SEMS) are available for malignant distal biliary obstruction: fully covered SEMS (FCSEMS) and uncovered SEMS. FCSEMS can prevent stent ingrowth, but a major concern is spontaneous migration. This study aimed to determine whether the additional insertion of a double-pigtail plastic stent to anchor the FCSEMS can prevent migration.

METHODS

68 patients with unresectable, malignant, distal, biliary obstruction were included in this multicenter, randomized, superiority trial. The patients were randomly assigned to receive either the FCSEMS plus an anchoring plastic stent (n = 33) or an FCSEMS alone (n = 35). After placement of the FCSEMS, the anchoring stent was inserted inside the FCSEMS. The primary outcome was the rate of stent migration during the 6-month follow-up. The secondary outcomes were stent-related adverse events, stent patency, and survival rates.

RESULTS

The baseline characteristics were similar between the two groups. The rate of stent migration at 6 months was significantly lower in patients with the FCSEMS plus anchoring stent (15 % vs. 40 %; P = 0.02). The mean stent patency was significantly longer in the FCSEMS plus anchoring group (237 days [95 % confidence interval [CI] 199 to 275] vs. 173 days [95 %CI 130 to 217]; P = 0.048). There were no significant differences in stent-related adverse events and overall survival rates at 6 months between the two groups.

CONCLUSIONS

Our data suggest that the additional double-pigtail plastic stent anchored the FCSEMS to prevent migration and prolonged patency without any serious adverse events.

Irradiation stent insertion for inoperable malignant biliary obstruction: a meta-analysis of randomized controlled trials

The purpose of the study was to compare the relative clinical efficacies of irradiation stent (IRS) and conventional stent (CVS) insertions for the treatment of patients with malignant biliary obstruction (MBO). Pubmed, Embase, and Cochrane Library databases were searched for relevant randomized controlled trials (RCTs) from the date of inception through to August 2020. Data analysis was performed using RevMan v5.3. This meta-analysis included eight RCTs which included a total of 319 patients who had undergone IRS insertion, and 328 who had undergone CVS insertion. No significant differences in pooled Δ total bilirubin values (MD 0.34; P = 0.92), incident rates of cholangitis (P = 0.47), hemobilia (P = 0.60), or pancreatitis (P = 0.89) were detected between two groups. The rate of stent dysfunction was significantly lower in the IRS group compared to the CVS group (22.2% vs. 37.7%, P = 0.02). The pooled stent patency (P < 0.00001) and survival (P < 0.00001) were significantly longer in the IRS group compared to the CVS group. Significant heterogeneity was detected in the endpoints of rate of stent dysfunction (I² = 52%; P = 0.08) and survival (I² = 77%; P = 0.0005). Subgroup analysis was performed based on the different IRS types and showed significantly longer survival in the IRS group based on both types of IRS. Funnel plot analyses did not detect any evidence of publication bias. This meta-analysis included eight RCTs which included a total of 319 patients who had undergone IRS insertion, and 328 who had undergone CVS insertion. No significant differences in pooled Δ total bilirubin values (MD 0.34; P = 0.92), incident rates of cholangitis (P = 0.47), hemobilia (P = 0.60), or pancreatitis (P = 0.89) were detected between 2 groups. The rate of stent dysfunction was significantly lower in the IRS group compared to the CVS group (22.2% vs. 37.7%, P = 0.02). The pooled stent patency (P < 0.00001) and survival (P < 0.00001) were significantly longer in the IRS group compared to the CVS group. Significant heterogeneity was detected in the endpoints of rate of stent dysfunction (I² = 52%; P = 0.08) and survival (I² = 77%; P = 0.0005). Subgroup analysis was performed based on the different IRS types and showed significantly longer survival in the IRS group based on both types of IRS. Funnel plot analyses did not detect any evidence of publication bias. Our meta-analysis demonstrates that IRS insertion can prolong stent patency and the survival of patients with MBO compared to CVS insertion.

Irradiation stent insertion for distal biliary obstruction secondary to primary common biliary cancer

PURPOSE

To assess the effectiveness and safety of irradiation stent insertion for patients with distal biliary obstruction (DBO) secondary to primary common biliary cancer.

MATERIAL AND METHODS

Eighty-two consecutive patients with DBO secondary to primary common biliary cancer were treated via either normal (n = 45) or irradiation stenting (n = 37) between January 2013 and December 2019. The instant and long-term outcomes were compared.

RESULTS

Technical success rates of normal and irradiation stenting were both 100%. Clinical success rates of normal and irradiation stenting were 91.1 and 100%, respectively (p = .179). Stent reobstruction was observed in 13 and 7 patients in the normal and irradiation stenting groups, respectively (p = .295). The median stent patency was 162 and 225 days in the normal and irradiation stenting groups, respectively (p < .001). The median survival was 178 and 250 days in the normal and irradiation stenting groups, respectively (p < .001). Cholangitis was, respectively, observed in 8 and 12 patients in normal and irradiation stenting groups (p = .124).

CONCLUSION

Irradiation stenting is effective and safe for patients with DBO secondary to primary common biliary cancer and can prolong stent patency and survival.

A stent with radioactive seed strand insertion for inoperable malignant biliary obstruction: A meta-analysis

PURPOSE

The purpose of the study was to assess the relative clinical effectiveness of stent insertion with or without radioactive seed strand (RSS) insertion in patients suffering from malignant biliary obstruction (MBO).

METHODS AND MATERIALS

Relevant articles published as of November 2020 in the Embase, PubMed, and Cochrane Library databases were identified and analyzed. Primary study endpoints for this meta-analysis were stent dysfunction, stent patency, and overall survival (OS), whereas secondary endpoints were rates of clinical success and complications. RevMan v5.3 was used to perform all meta-analyses.

RESULTS

In total, there were nine studies incorporating 643 patients (280 and 363 who underwent stent insertion with and without RSS, respectively). No differences were observed between these groups with respect to pooled rates of clinical success (p = 0.25), stent dysfunction (p = 0.47), cholangitis (p = 0.97), cholecystitis (p = 0.95), or pancreatitis (p = 0.66). However, stent patency duration (p < 0.00001) and patients' OS (p < 0.00001) were significantly increased in patients in the stent + RSS group. No heterogeneity was detected for any of these endpoints, nor did funnel plots yield any publication bias. A subgroup analysis of patients with hilar MBO similarly exhibited stent + RSS insertion to be associated with longer stent patency and OS as compared with stent insertion alone.

CONCLUSIONS

These findings showed that relative to stent insertion, stent + RSS insertion is associated with longer OS and stent patency in patients with inoperable MBO.

Stent Insertion With High Intensity-Focused Ultrasound Ablation for Biliary Obstruction Caused by Pancreatic Carcinoma: A Randomized Controlled Trial

PURPOSE

This study was designed to assess the clinical efficacy of stent insertion with high intensity-focused ultrasound ablation (HIFUA) in patients with malignant biliary obstruction (MBO) as a consequence of pancreatic carcinoma (PC).

MATERIALS AND METHODS

This was a single-center, open-label, prospective, randomized controlled trial. Consecutive patients with MBO caused by PC were randomly assigned to undergo stent insertion with or without HIFUA from June 2019 to February 2020. This study was registered at ClinicalTrials.gov (NCT03962478).

RESULTS

In total, 92 patients were enrolled in this study and assigned to the stent-only (n=46) or combined (stent+HIFUA; n=46) treatment groups. Stent insertion was associated with a 100% technical success rate. For patients in the combination treatment group, 26, 18, and 2 patients underwent 2, 3, and 4 cycles of HIFUA, respectively. A positive clinical response to HIFUA treatment was noted in 38 patients (82.6%). Stent dysfunction was detected in 9 and 15 patients in the combination and stent-only groups, respectively (P=0.154), while median stent patency in these 2 groups was 188 and 120 days, respectively (P<0.001). All patients died over the course of the follow-up, with median survival periods of 218 and 140 days in the combination and stent-only treatment groups, respectively (P=0.001). The only detected predictor of prolonged survival was HIFUA treatment (P=0.004), and there were no significant differences in complication rates between these 2 treatment groups.

CONCLUSION

A combination of stent insertion and HIFUA can improve stent patency and overall survival in patients suffering from MBO because of PC relative to stent insertion alone.

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.

Stent insertion with high-intensity focused ultrasound ablation for malignant biliary obstruction: A protocol of systematic review and meta-analysis

BACKGROUND

This meta-analysis was conducted in order to understand the clinical efficacy of stent insertion with high-intensity focused ultrasound (HIFU) ablation for the treatment of malignant biliary obstruction (MBO).

METHODS

The Pubmed, Embase, and Cochrane Library databases were searched for all relevant studies published through July 2020. The meta-analysis was conducted using RevMan v5.3, with analyzed study endpoints including the rate of stent dysfunction, time to stent dysfunction, stent patency, complication rate, and overall survival (OS).

RESULTS

In total, 35 potentially relevant studies were initially identified, of which 6 were ultimately included in the present meta-analysis. These 6 studies included 429 MBO patients that were treated either only via stenting (n = 221) or via stenting in combination with HIFU ablation (n = 208). Pooled stent dysfunction rates in the stent and stent with HIFU groups were 25.9% and 18.0%, respectively (OR: 1.59; 95% CI: 0.88, 2.84, P = .12). The average time to stent dysfunction was significantly longer in the stent with HIFU group relative to the stent group (MD: -3.15; 95% CI: -3.53, -2.77, P < .0001). Pooled complication rates in the stent and stent with HIFU groups were 17.1% and 19.6%, respectively (OR: 0.88; 95% CI: 0.49, 1.58, P = .67). Stent patency and OS were both significantly longer in the stent with HIFU group relative to the stent group (P < .0001 and.0001, respectively). Funnel plot analyses did not reveal any significant evidence of publication bias linked to the selected study endpoints.

CONCLUSIONS

This meta-analysis found that a combined stenting and HIFU ablation approach can achieve better stent patency and OS in MBO patients relative to stent insertion alone.

Covered vs bare stent for distal malignant biliary obstruction due to primary common biliary cancer

This study was designed as a means of comparing the clinical efficacy and long-term outcomes of covered vs bare stent insertion as a treatment for distal malignant biliary obstruction (DMBO) caused by primary common biliary cancer (PCBC).This retrospective study was designed using data collected between January 2012 and December 2019 to assess the short- and long-term outcomes in patients with DMBO caused by PCBC treated by inserting either bare or covered stents were compared.Ninety two patients with DMBO caused by PCBC were divided between bare (n = 51) or covered (n = 41) stent groups. Technical success rates in both groups were 100%. Clinical success of bare vs covered stent use were 96.1% and 97.6% (P = 1.00). Stent dysfunction was seen in 17 and 6 patients in the bare and covered stent groups, respectively (P = .04). The median stent patency for bare and covered stents was 177 and 195 days, respectively (P = .51). The median survival was 188 and 200 days in the bare and covered stent groups, respectively (P = .85).For patients with DMBO caused by PCBC, using bare vs covered stents yields similar clinical efficacy and long term outcomes.

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.

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.

Current Endoscopic Management of Malignant Biliary Stricture

Biliary and pancreatic cancers occur silently in the initial stage and become unresectable within a short time. When these diseases become symptomatic, biliary obstruction, either with or without infection, occurs frequently due to the anatomy associated with these cancers. The endoscopic management of these patients has changed, both with time and with improvements in medical devices. In this review, we present updated and integrated concepts for the endoscopic management of malignant biliary stricture. Endoscopic biliary drainage had been indicated in malignant biliary obstruction, but the concept of endoscopic management has changed with time. Although routine endoscopic stenting should not be performed in resectable malignant distal biliary obstruction (MDBO) patients, endoscopic biliary drainage is the treatment of choice for palliation in unresectable MDBO patients. Self-expanding metal stents (SEMS) have better stent patency and lower costs compared with plastic stents (PS). For malignant hilum obstruction, PS and uncovered SEMS yield similar short-term outcomes, while a covered stent is not usually used due to a potential unintentional obstruction of contralateral ducts.

Stent insertion with high-intensity focused ultrasound ablation for distal biliary obstruction secondary to pancreatic carcinoma

We determined the clinical effectiveness and long-term outcomes in patients with distal biliary obstruction (DBO) secondary to pancreatic carcinoma (PC) who were treated by self-expanded metallic stent (SEMS) insertion with or without high-intensity focused ultrasound (HIFU) ablation.From January 2014 to December 2018, consecutive patients with DBO secondary to PC underwent SEMS insertion with or without HIFU ablation in our center. The long-term outcomes were compared between the 2 groups.During the included period, 75 patients underwent SEMS insertion with (n = 34) or without (n = 41) HIFU ablation in our center. SEMS insertion was successfully performed in all patients. Liver function was significantly improved after SEMS insertion in both groups. An average of 2.9 HIFU treatment sessions per patient were performed. Twenty patients (stent + HIFU group: 7; stent-only group: 13) experienced stent dysfunction (P = .278). The clinical response rate to HIFU ablation was 79.4%. The median stent patency was significantly longer in the stent with HIFU group than in the stent-only group (175 vs 118 days, P = .005). The median survival was significantly longer in the stent with HIFU group compared with the stent-only group (211 versus 136 days, P = .004). An Eastern Cooperative Oncology Group (ECOG) Performance Status of 3 (hazard ratio: 0.300; P = .002) and subsequent HIFU ablation (hazard ratio: 0.508; P = .005) were associated with prolonged survival.HIFU ablation following stent insertion can prolong the stent patency and survival for patients with DBO secondary to PC.

Predictors of stent occlusion in patients with unresectable pancreatic cancer after biliary metal stents

BACKGROUND

Self-expandable metal stents (SEMS) are a widely accepted biliary endoprosthesis for patients with unresectable malignant biliary obstruction. Here, we identified predictors for the occlusion of SEMS in unresectable pancreatic cancer patients with biliary tract obstruction.

METHODS

Patients with a distal malignant biliary obstruction caused by unresectable pancreatic cancer who received partially covered SEMS (PC-SEMS) placement for the first time between January 2003 and January 2016 were retrospectively enrolled for analysis. The rates of PC-SEMS occlusion were evaluated. The possible predictors of PC-SEMS occlusion were analyzed using Cox regression analysis.

RESULTS

In total, 120 patients who received PC-SEMS for unresectable pancreatic cancer were identified. The rate of PC-SEMS occlusion was 37%. The median time to occlusion of PC-SEMS was 359 days. The major causes of occlusion included biliary sludge (61%) and tumor ingrowth (30%). Cox multivariate regression analysis revealed that inadequate alkaline phosphatase/gamma-glutamyl transferase decline (defined by a decrease of <50% within 2 wk after PC-SEMS placement) was the only independent predictor of stent occlusion (hazard ratio, 2.86; 95% CI, 1.28-6.25; p = 0.01) CONCLUSION:: Inadequate alkaline phosphatase/gamma-glutamyl transferase decline is a predictor of occlusion of first-time PC-SEMS placement in unresectable pancreatic cancer patients with biliary tract obstruction.

No evidence of improved efficacy of covered stents over uncovered stents in percutaneous palliation of malignant hilar biliary obstruction: results of a prospective randomized trial

OBJECTIVE

To investigate whether covered stents show a higher efficacy than uncovered stents in percutaneous treatment of malignant hilar biliary obstruction.

METHODS

Patients with obstructive jaundice caused by an unresectable hilar malignancy were included after failed endoscopic intervention in a prospective randomized trial comparing expanded polytetrafluoroethylene and fluorinated ethylene propylene (ePTFE-FEP)-covered nitinol stents with uncovered nitinol stents. Exclusion criteria were as follows: primary tumors existing more than 3 months, a biliodigestive anastomosis, previous stenting, and a Karnofsky score of less than 50. Safety, clinical success, and adjuvant chemotherapy were compared as well as occlusion rate, patency, and survival.

RESULTS

A total of 120 patients were included. One patient was post hoc excluded. Fourteen patients who died within 7 days and one patient without patency data were excluded from patency analysis. Serious adverse events (p = 0.4), 30-day mortality (p = 0.5), and clinical success (p = 0.8) were equivalent for both stent groups. Twenty-one out of 61 (34%) patients in the covered and 24/58 (41%) in the uncovered stent groups received adjuvant chemotherapy (p = 0.5). Occlusion rate was 54% (27/50) in the covered stent group and 57% (31/54) in the uncovered stent group (p = 0.8). Median patency was 229 days (95% CI 113-345) for covered stents and 130 days (95% CI 75-185) for uncovered stents (p = 0.1). Median survival in patients with covered stents was 79 days (95% CI 52-106) and with uncovered stents 92 days (95% CI 60-124) (p = 0.3).

CONCLUSION

In malignant hilar biliary obstruction, there is no evidence that ePTFE-FEP-covered stents are superior to uncovered stents in terms of safety, clinical success, adjuvant chemotherapy, patency, or survival.

KEY POINTS

• Percutaneous palliation of hilar biliary obstruction is feasible with both uncovered and covered stents. • Clinical success in terms of bilirubin decrease and adjuvant chemotherapy is achievable with both stents. • Thirty-day mortality is considerable when stenting is also offered to patients with a low performance status.

Stenting for Benign and Malignant Biliary Strictures

Benign and malignant biliary strictures are common indications for endoscopic retrograde cholangiopancreatography. Diagnosis involves high-quality cross-sectional imaging and cholangiography with various endoscopic sampling techniques. Treatment options include placement of plastic biliary stents and self-expanding metal stents, which differ in patency duration and cost effectiveness. Whether the etiology is benign or malignant, a multidisciplinary strategy should be implemented. This article will discuss general principles of biliary stenting in both benign and malignant conditions.

Palliative therapy in pancreatic cancer-interventional treatment with stents

Interventional treatment with stents in pancreatic cancer is a topic that developed during recent years and new fields of palliative stent therapy have evolved. The increasing life expectancy of patients with unresectable pancreatic cancer increases the need for clinical and cost effective therapeutic interventions. Current literature, guidelines, practice and evidence were reviewed. Besides the most obvious biliary stenting via endoscopic retrograde cholangiopancreatography (ERCP), pancreatic and gastroduodenal stenting as well as percutaneous transhepatic cholangiography (PTC) and the rapidly growing field of endosonographic stent implantation in the palliative care of patients with pancreatic cancer are being discussed from several points of view in this review.

Study of Percutaneous Stent Placement with Iodine-125 Seed Strand for Malignant Biliary Obstruction

PURPOSE

To evaluate the effectiveness and safety of simultaneous placement of a self-expandable metallic stents (SEMS) and iodine-125 seed strand in the management of malignant obstructive jaundice (MOJ).

MATERIALS AND METHODS

This study included 132 patients with MOJ treated from November 2015 to October 2017. Forty-five patients underwent insertion of SEMS with iodine-125 seed strands (Seeds group); the remaining 87 patients underwent SEMS placement alone (Control group). Technical success was defined as accurate, successful deployment of SEMS with or without iodine-125 seed strand; clinical success was defined as 20% reduction in serum bilirubin within 1 week after the procedure, compared with baseline. Complications, duration of primary stent patency, and overall survival were evaluated.

RESULTS

Technical success was achieved in all patients in both groups. In the Seeds group, an average of 14 seeds (range 8-22) were implanted in the bile duct as a strand. Clinical success rates were similar between the groups (Seeds group, 93.3%; Control group, 95.4%). Major complications occurred in only one patient, in the Control group. The median period of primary stent patency was significantly longer in the Seeds group (194 days) than in the Control group (86 days; P = 0.049). The median overall survival was also significantly longer in the Seeds group (194 days) than in the Control group (96 days; P = 0.031).

CONCLUSION

SEMS combined with iodine-125 seed strands is effective and safe in the management of MOJ and can improve stent patency and patient survival.

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

BACKGROUND AND AIMS

Self-expandable metal stents (SEMSs) are used to relieve malignant biliary obstructions. We aimed to compare stent patency, the adverse events rate, and overall survival of covered versus uncovered self-conformable metal stents in patients with primary malignant extrahepatic biliary strictures, not eligible for surgery.

METHODS

This is a multicenter randomized trial analyzing 158 patients with inoperable distal malignant biliary obstruction conducted in 5 Italian referral centers between December 2014 and October 2016. Seventy-eight patients were randomized to receive a fully covered SEMS (FCSEMS), and 80 patients received uncovered SEMSs (USEMSs). Data from 148 (72 FCSEMSs and 76 USEMSs) of 158 patients were analyzed.

RESULTS

Median time of stent patency was lower for FCSEMSs (240 days vs 541 days for USEMSs; P = .031). Adverse events occurred with 19 FCSEMSs (26.4%) and 10 USEMSs (13.2%); P = .061. The main causes of FCSEMS dysfunction were migration (7% vs 0% in the USEMS group) and early occlusion mainly because of sludge or overgrowth; late stent occlusion because of tumor ingrowth occurred in 13.2% of patients in the USEMS group. There were no significant differences either in levels of conjugated bilirubin improvement or in overall survival between the FCSEMS and USEMS groups. Median survival was 134 days in the FCSEMS group and 112 days in the USEMS group (P = .23).

CONCLUSION

The number of stent-related adverse events was higher, although not significantly, among patients in the FCSEMS group. FCSEMSs had a significantly higher rate of migration than USEMSs, and stent occlusion occurred earlier. A significant difference in the patency rate was observed in favor of the USEMS group. (Clinical trial registration number: NCT02102984.).

Efficacy of a Multiplex Paclitaxel Emission Stent Using a Pluronic® Mixture Membrane versus a Covered Metal Stent in Malignant Biliary Obstruction: A Prospective Randomized Comparative Study

Background/Aims

A drug-eluting stent for unresectable malignant biliary obstruction was developed to increase stent patency by preventing tumor ingrowth. The safety and efficacy of a new generation of metallic stents covered with a paclitaxel-incorporated membrane using a Pluronic^® mixture (MSCPM-II) were compared prospectively with those of covered metal stents (CMSs) in patients with malignant biliary obstructions.

Methods

This study was initially designed as a prospective randomized trial but was closed early because of a high incidence of early occlusion. Therefore, the data were analyzed using the intent-to-treat method. A total of 72 patients with unresectable distal malignant biliary obstructions were prospectively enrolled.

Results

The two groups did not differ significantly in basic characteristics and mean follow-up period (MSCPM-II 194 days vs CMS 277 days, p=0.063). Stent occlusion occurred in 14 patients (35%) who received MSCPM-II and in seven patients (21.9%) who received CMSs. Stent patency and survival time did not significantly differ between the two groups (p=0.355 and p=0.570). The complications were mild and resolved by conservative management in both groups.

Conclusions

There were no significant differences in stent patency or patient survival in MSCPM-II and CMS patients with malignant biliary obstructions.

Partially covered metal stents have longer patency than uncovered and fully covered metal stents in the management of distal malignant biliary obstruction: a retrospective study

BACKGROUND

Self-expandable metal stents (SEMSs) are widely used for malignant biliary obstructions. Nitinol-covered SEMSs have been developed to improve stent patency. Currently, SEMSs may be uncovered, partially covered, or fully covered; however, there is no consensus on the best stent type for the management of malignant distal biliary obstruction (MDBO).

METHODS

Patients with unresectable MDBO receiving SEMS (Wallflex™) were retrospectively analyzed. Time to recurrent biliary obstruction (TRBO) and survival time were compared among the three types of SEMSs. Univariate and multivariate analyses were performed to identify risk factors for stent dysfunction.

RESULTS

In total, 101 patients received SEMSs for unresectable MDBO (44 uncovered, 28 partially covered, and 29 fully covered SEMSs). Median survival time was 200, 168, and 276 days in the uncovered, partially covered, and fully covered SEMSs groups, respectively. There were no differences in survival among the three groups. Median TRBO was 199, 444, and 194 days in the uncovered, partially covered, and fully covered SEMSs groups, respectively. Partially covered SEMSs had longer TRBO than uncovered (p = 0.013) and fully covered (p = 0.010) SEMSs. Tumor ingrowth occurred only with uncovered SEMSs and stent migration occurred only with fully covered SEMSs. Multivariate analyses confirmed that partially covered SEMSs have lower risk of dysfunction.

CONCLUSIONS

Partially covered SEMSs with a proximal uncovered flared end have longer patency than uncovered and fully covered SEMSs by preventing tumor ingrowth and stent migration.

A Case Series: Outcomes of Endoscopic Biliary Self-Expandable Metal Stent for Malignant Biliary Obstruction with Surgically Altered Anatomy

BACKGROUND

Few studies have reported the outcomes of self-expandable metal stent (SEMS) placement for malignant biliary obstruction in patients with surgically altered anatomy.

AIMS

To evaluate the outcomes of biliary metal stent placement with the use of a short-type single-balloon enteroscope (working length, 1520 mm; channel diameter, 3.2 mm) in such patients.

METHODS

We retrospectively studied 13 malignant biliary obstructions treated by SEMS placement. Technical success rate, functional success rate, time to recurrent biliary obstruction (RBO), and complications were evaluated.

RESULTS

Technical success rate was 100 % (13/13), functional success rate was 92 % (12/13), and the median time to RBO was 247 days (95 % CI 205.6-285.5). Complications comprised mild pancreatitis in one patient. Uncovered SEMSs were placed in three obstructions, partially covered SEMS in five obstructions, and fully covered SEMSs in five obstructions. Three stents occluded (two ingrowths and one mucosal hyperplasia), and one symptomatic distal stent migration occurred after more than 30 days from placement.

CONCLUSIONS

A short-type single-balloon enteroscope was useful for the placement of various SEMS in this patient population with satisfactory outcomes.

Covered Stents versus Uncovered Stents for Unresectable Malignant Biliary Strictures: A Meta-Analysis

Aim. To summarize the covered or uncovered SEMS for treatment of unresectable malignant distal biliary obstruction, comparing the stent patency, patient survival, and incidence of adverse events between the two SEMSs. Methods. The meta-analysis search was performed independently by two of the authors, using MEDLINE, EMBASE, OVID, and Cochrane databases on all studies between 2010 and 2015. Pooled effect was calculated using either the fixed or the random effects model. Results. Statistics shows that there is no difference between SEMSs in the hazard ratio for patient survival (HR 1.04; 95% CI, 0.92–1.17; P = 0.55) and stent patency (HR 0.87, 95% CI: 0.58 to 1.30, P = 0.5). However, incidence of adverse events (OR: 0.74, 95% CI: 0.57 to 0.97, P = 0.03) showed significant different results in the covered SEMS, with dysfunctions events (OR: 0.75, 95% CI: 0.56 to 1.00, P = 0.05) playing a more important role than complications (OR: 0.87, 95% CI: 0.58 to 1.30, P = 0.50). Conclusions. Covered SEMS group had lower incidence of adverse events. There is no significant difference in dysfunctions, but covered SEMS trends to be better, with no difference in stent patency, patient survival, and complications.

Malignant Biliary Obstruction: Evidence for Best Practice

What should be done next? Is the stricture benign? Is it resectable? Should I place a stent? Which one? These are some of the questions one ponders when dealing with biliary strictures. In resectable cases, ongoing questions remain as to whether the biliary tree should be drained prior to surgery. In palliative cases, the relief of obstruction remains the main goal. Options for palliative therapy include surgical bypass, percutaneous drainage, and stenting or endoscopic stenting (transpapillary or via an endoscopic ultrasound approach). This review gathers scientific foundations behind these interventions. For operable cases, preoperative biliary drainage should not be performed unless there is evidence of cholangitis, there is delay in surgical intervention, or intense jaundice is present. For inoperable cases, transpapillary stenting after sphincterotomy is preferable over percutaneous drainage. The use of plastic stents (PS) has no benefit over Self-Expandable Metallic Stents (SEMS). In case transpapillary drainage is not possible, Endoscopic Ultrasonography- (EUS-) guided drainage is still an option over percutaneous means. There is no significant difference between the types of SEMS and its indication should be individualized.

Choosing the appropriate strategy in managing malignant biliary obstruction

Most patients with pancreatic cancer develop malignant biliary obstruction. Treatment of obstruction is generally indicated to relieve symptoms and improve morbidity and mortality. First-line therapy consists of endoscopic biliary stent placement. Recent data comparing plastic stents to self-expanding metallic stents (SEMS) have shown improved patency with SEMS. The decision of whether to treat obstruction and the means for doing so depend on the clinical scenario. For patients with resectable disease, preoperative biliary decompression is only indicated when surgery will be delayed or complications of jaundice exist. For patients with locally advanced disease, self-expanding metal stents are superior to plastic stents for long-term patency. For patients with advanced disease, the choice of metallic or plastic stent depends on life expectancy. When endoscopic stent placement fails, EUS guided biliary drainage, percutaneous transhepatic biliary drainage or surgical treatments are appropriate.