Placement of a metallic stent across the main duodenal papilla may predispose to cholangitis

Safety and efficacy of biliary suprapapillary metal and plastic stents in malignant biliary obstruction: a systematic review and meta-analysis

BACKGROUND AND AIMS

Biliary drainage is vital in managing malignant biliary obstruction (MBO). Suprapapillary stenting has emerged as a viable alternative to transpapillary stenting and is performed using inside plastic (iPS) or metal stents (iMS). This meta-analysis aims to evaluate the outcomes of suprapapillary stent placement for MBO.

METHODS

The Embase, PubMed, and Web of Science databases were systematically searched to include all studies published before September 31, 2023, that reported on the outcomes of suprapapillary stents placed for MBO. Using the random-effect model, the pooled, weight-adjusted event rate estimate for the clinical outcomes was calculated with 95% confidence intervals (CIs).

RESULTS

Twenty-eight studies were included, with a total of 1401 patients. The pooled clinical success rate was 98.9%. A subgroup analysis yielded non-significant differences between the iPS and iMS groups (99.3% vs. 98.6%, respectively; P = 0.44). The pooled incidence rate of adverse events (AE) with suprapapillary stents was 9.5%. In a subgroup analysis, the incidence of AEs with iPS was 10.7% compared to 9% in the iMS group without a statistical difference (P = 0.32). The most common adverse event was cholangitis (2.2%), followed by pancreatitis (1.1%), cholecystitis (0.5%), and bleeding (0.12%).

CONCLUSION

When technically feasible, suprapapillary stenting for MBO is a viable endoscopic option with a high clinical success rate and acceptable adverse event rates. Both iPS and iMS exhibit similar efficacy.

Meta-analysis on clinical outcomes of suprapapillary versus transpapillary stent insertion in malignant biliary obstruction

BACKGROUND/AIMS

Endoscopic biliary stenting is an essential treatment for malignant biliary obstruction (MBO). However, the optimal location for the placement of metal stents (MS) or plastic stents (PS) during the management of MBO, whether above (suprapapillary) or across (transpapillary) the sphincter of Oddi (SO), has not been thoroughly evaluated. This meta-analysis aims to compare the clinical outcomes associated with endoscopic retrograde cholangiopancreatography (ERCP)-guided biliary stents placed above and across the SO in patients with MBO.

METHODS

A comprehensive search of electronic databases was carried out to identify studies published from inception to April 2022. The clinical outcomes examined including stent patency, stent occlusion, and overall adverse events (AEs) such as cholangitis, post-ERCP pancreatitis (PEP), cholecystitis, stent migration, and bleeding. The selection of a random-effects model or fixed-effects model was based on the presence of heterogeneity.

RESULTS

A total of 12 articles involving 751 patients were analyzed. The findings showed that the suprapapillary approach had longer stent patency compared to the transpapillary approach (mean difference: 38.58; 95% confidence interval 16.02-61.14, P < 0.0001). Additionally, the suprapapillary approach was associated with a lower risk of stent occlusion and overall AEs (P = 0.04, P = 0.002, respectively), particularly in the incidence of PEP (P = 0.009). The incidence of cholangitis, cholecystitis, stent migration, and bleeding were similar between the suprapapillary and transpapillary approaches. The subgroup analyses indicated that suprapillary PS had a significant decrease in the incidence of stent occlusion and longer stent patency, while suprapillary MS had a significant decrease in the incidence of overall AEs and PEP than the transpapillary approach.

CONCLUSION

Compared with the transpapillary approach, the suprapapillary stent had superiority in longer stent patency, lower rates of stent occlusion and overall AEs, and notably, a lower incidence of PEP. The incidence of cholangitis, cholecystitis, stent migration, and bleeding were similar between the suprapapillary and transpapillary approaches. Further large-scale randomized controlled studies are needed to confirm our findings.

REGISTRATION NO

CRD42022336435.

Suprapapillary placement of plastic versus metal stents for malignant biliary hilar obstructions: a multicenter, randomized trial

BACKGROUND AND AIMS

The efficacy of the suprapapillary placement of inside plastic stents (iPSs) for unresectable malignant hilar biliary obstructions (MHOs) is unknown compared with that of uncovered inside metal stents (iMSs). This randomized controlled trial was designed to evaluate the outcomes of endoscopic placement of these stents for unresectable MHOs.

METHODS

This open-label, randomized study was conducted at 12 Japanese institutions. The enrolled patients with unresectable MHOs were allocated to iPS and iMS groups. The primary outcome was defined as the time to recurrent biliary obstruction in patients for whom the intervention was both technically and clinically successful.

RESULTS

Among 87 enrollments, 38 patients in the iPS group and 46 patients in the iMS group were analyzed. Technical success rates were 100% (38 of 38) and 96.6% (44 of 46), respectively (P = 1.00). After transferring 1 unsuccessful iMS-group patient to the iPS group (since iPSs were deployed), the clinical success rates were 90.0% (35 of 39) for the iPS group and 88.9% (40 of 45) for the iMS group from a per-protocol analysis (P = 1.00). Among the patients with clinical success, the median times to recurrent biliary obstruction were 250 (95% confidence interval, 85-415) and 361 (95% confidence interval, 107-615) days (log-rank test, P = .34). No differences were detected in rates of adverse events.

CONCLUSIONS

This Phase II randomized trial did not show any statistically significant difference in stent patency between suprapapillary plastic versus metal stents. Considering the potential advantages of plastic stents for malignant hilar obstruction, these findings suggest that suprapapillary plastic stents could be a viable alternative to metal stents for this condition.

Predicting early biliary infection after stenting of malignant biliary obstruction: model development and internal validation

PURPOSE

To analyze the risk factors and develop a clinical prediction model for early biliary infection (EBI) after percutaneous transhepatic biliary stenting (PTBS) in patients with malignant biliary obstruction (MBO).

METHODS

The clinical data of 236 patients with MBO treated with PTBS from June 2012 to June 2021 were retrospectively analyzed. Independent risk factors were analyzed by univariate and multivariate logistic regression, and a nomogram model was constructed based on the results. Discrimination, calibration, and clinical usefulness of this model were further assessed.

RESULTS

The technical success rate of PTBS was 100%, and EBI after PTBS was 20.3%. Multivariate logistic regression analysis showed that hilar MBO (P = 0.020), diabetes (P = 0.001), previous surgical or endoscopic intervention (P = 0.007), procedure time > 60 min (P = 0.007), and intraprocedural biliary hemorrhage (P = 0.003) were independent risk factors for EBI after PTBS. A nomogram model was developed to predict the probability of EBI. ROC curves showed good discrimination of the model (area under curve = 0.831). The calibration plot indicated that the predicted probability of EBI by this model was in good agreement with the actual probability of EBI. The DCA curves showed that the net benefit of nomogram-assisted decisions was higher than or equal to the net benefit of treatment for all or none at a wide threshold probability (0-0.8).

CONCLUSION

The nomogram model based on the above independent risk factors can predict the probability of EBI and model-assisted treatment decisions contribute to improved clinical outcome. Therefore, MBO patients with probability of EBI > 0.20 based on the model should be recommended for perioperative broad-spectrum antibiotics and close monitoring.

Novel anti-reflux biliary metal stent with a distal tapered end for distal malignant biliary obstruction: a feasibility study

Background and study aims  We developed a self-expandable metallic stent (SEMS) with a distal tapered end to reproduce the physiological bile flow with a pressure gradient due to the difference in the diameter. We aimed to evaluate the safety and efficacy of the newly developed distal tapered covered metal stent (TMS) for distal malignant biliary obstruction (DMBO). Patients and methods  This single-center, prospective, single-arm study was conducted in patients with DMBO. The primary endpoint was time to recurrent biliary obstruction (TRBO), and the secondary endpoints were the survival time and incidence of adverse events (AEs). Results  Thirty-five patients (15 men, 20 women; median age, 81 years [range: 53-92]) were enrolled between December 2017 and December 2019. The primary diseases were pancreatic head cancer in 25 cases, bile duct cancer in eight cases, and ampullary cancer in two cases. TMS was successfully placed in all cases. Acute cholecystitis occurred as an early AE (within 30 days) in two cases (5.7 %). The median TRBO was 503 days, median survival time was 239 days. RBO was observed in 10 cases (28.6 %), and the causes were distal migration in six cases, proximal migration in two cases, biliary sludge in one case, and tumor overgrowth in one case. Conclusions  Endoscopic placement of the newly developed TMS in patients with DMBO is technically feasible and safe, and the TRBO was remarkably long. The anti-reflux mechanism based on the difference in diameter may be effective, and a randomized controlled trial with a conventional SEMS is required.

Outcomes of Intraductal Placement of Covered Metal Stents for Unresectable Distal Malignant Biliary Obstruction

Intraductal self-expandable metal stent (SEMS) placement may prolong stent patency by reducing duodenobiliary reflux. This study aimed to evaluate the efficacy and safety of this biliary drainage method in patients with unresectable distal malignant biliary obstruction (MBO). Consecutive patients with unresectable MBO who underwent initial covered SEMS placement between 2015 and 2022 were retrospectively reviewed. We compared the causes of recurrent biliary obstruction (RBO), time to RBO (TRBO), adverse events (AEs), and reintervention rates between two biliary drainage methods (SEMSs placed above and across the papilla). A total of 86 patients were included (above: 38 and across: 48). Overall RBO rates (24% vs. 44%, p = 0.069) and median TRBO (11.6 months vs. 9.8 months, p = 0.189) were not significantly different between the two groups. The frequency of overall AEs was similar between the two groups in the entire cohort, but was significantly lower in patients with non-pancreatic cancer (6% vs. 44%, p = 0.035). Reintervention was successfully performed in the majority of patients in both groups. Intraductal SEMS placement was not associated with a prolonged TRBO in this study. Larger studies are warranted to further evaluate the benefit of intraductal SEMS placement.

Suprapapillary Biliary Stents Have Longer Patency Times than Transpapillary Stents-A Systematic Review and Meta-Analysis

BACKGROUND AND STUDY AIMS

Endoscopic biliary stent placement is a minimally invasive intervention for patients with biliary strictures. Stent patency and function time are crucial factors. Suprapapillary versus transpapillary stent positioning may contribute to stent function time, so a meta-analysis was performed in this comparison.

METHODS

A comprehensive literature search was conducted in the CENTRAL, Embase, and MEDLINE databases to find data on suprapapillary stent placement compared to the transpapillary method via endoscopic retrograde cholangiopancreatography in cases of biliary stenosis of any etiology and any stent type until December 2020. We carried out a meta-analysis focusing on the following outcomes: stent patency, stent migration, rate of cholangitis and pancreatitis, and other reported complications.

RESULTS

Three prospective and ten retrospective studies involving 1028 patients were included. Suprapapillary stent placement appeared to be superior to transpapillary stent positioning in patency (weighted mean difference = 50.23 days, 95% CI: 8.56, 91.98; p = 0.0.018). In a subgroup analysis of malignant indications, suprapapillary positioning showed a lower rate of cholangitis (OR: 0.34, 95% CI: 0.13, 0.93; p = 0.036). Another subgroup analysis investigating metal stents in a suprapapillary position resulted in a lower rate of pancreatitis (OR: 0.16, 95% CI: 0.03, 0.95; p = 0.043) compared to transpapillary stent placement. There was no difference in stent migration rates between the two groups (OR: 0.67, 95% CI: 0.17, 2.72; p = 0.577).

CONCLUSIONS

Based on our results, suprapapillary biliary stenting has longer stent patency. Moreover, the stent migration rate did not differ between the suprapapillary and transpapillary groups.

The efficacy and safety of a duckbill-type anti-reflux metal stent as the initial metal stent for distal malignant biliary obstruction in unresectable pancreatic cancer

Background

The usefulness of duckbill-type anti-reflux metal stent (DMS) in self-expandable metal stent-naïve pancreatic cancer (PC) patients has not been well-studied. This study aimed to evaluate the efficacy and safety of DMS in such patients.

Methods

We analyzed consecutive patients with unresectable PC who received a covered metal stent (CMS) as the initial self-expandable metal stent at our institution. Technical success, functional success, causes of recurrent biliary obstruction (RBO), time to RBO (TRBO), adverse events (AEs), and reintervention rates were compared between DMS and conventional CMS (c-CMS).

Results

A total of 69 patients were included (DMS: 28, c-CMS: 41). Technical success, functional success, and AEs were similar between groups. Tumor ingrowth was more common in the DMS group (18% vs. 0%, p = 0.009), while non-occlusion cholangitis tended to be more common in the c-CMS group (0% vs. 15%, p = 0.074). Median time to RBO was similar between groups (276 vs. 273 days, p = 0.915). The anti-reflux valve of DMS was found torn in 56% of patients. Endoscopic reintervention was successful in all cases, despite failed stent removal in 88% of patients in the DMS group.

Conclusions

DMS was not associated with longer time to RBO compared to c-CMS in self-expandable metal stent-naïve patients.

Safety and Efficacy of a Large-Bore Biliary Metallic Stent for Malignant Biliary Obstruction

Self-expandable metallic stents (SEMSs) are typically inserted in patients with unresectable malignant biliary obstruction. However, SEMSs are susceptible to occlusion. To overcome this issue, we developed a large-bore, dumbbell-shaped, fully covered SEMS (FCSEMS-L) and compared its efficacy and safety with those of a conventional FCSEMS (FCSEMS-C) in patients with malignant biliary obstruction. Methods: Patients with unresectable distal malignant biliary obstruction were retrospectively enrolled between January 2011 and February 2021. All patients underwent endoscopic insertion of FCSEMSs. Recurrent biliary obstruction (RBO), patient survival time, complications, and prognosis were analyzed. Results: RBO occurred in 31 patients (35.6%) who received an FCSEMS-L, and in 34 (45.9%) who received an FCSEMS-C. Stent occlusion occurred in 19 patients (21.8%) who received an FCSEMS-L, and in 22 (29.7%) who received an FCSEMS-C. Stent migration occurred in 12 patients (13.8%) with an FCSEMS-L and 12 (16.2%) with an FCSEMS-C. The median time to RBO (TRBO) was 301 days with an FCSEMS-L and 203 days with an FCSEMS-C. The median survival time was 479 days with an FCSEMS-L and 523 days with an FCSEMS-C. The TRBO and patient survival time did not significantly differ between the two groups. Conclusions: There were no significant differences in efficacy and complication rates between the fully covered large bore SEMSs and conventional fully covered SEMSs.

Angle of covered self-expandable metallic stents after placement is a risk factor for recurrent biliary obstruction

BACKGROUND

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

AIM

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

METHODS

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

RESULTS

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

CONCLUSION

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

Risk factors for biliary stent infections in malignant biliary obstruction secondary to unresectable malignancies

BACKGROUND

Palliative biliary drainage in patients with unresectable malignant biliary obstruction (MBO) frequently leads to biliary stent infection (BI), which could impact medical care. The aim of this study was to assess the risk factors for BI occurrence in patients after stenting procedure and the impact of BI on patient survival.

METHODS

All consecutive patients hospitalized from 2014 to 2018 for MBO and biliary stenting were retrospectively included. Demographic, clinical, and microbiological characteristics of each BI episode during a 1-year follow-up were described. Documented BI was defined as the association of BI episode and confirmed blood stream infection (BSI). Univariate and multivariate analyses were performed to evaluate risk factors for the first BI occurrence.

RESULTS

Among 180 patients, 56% were men (mean age of 69±12), and 54% have pancreatic cancer, 16% biliary cancer, 2% hepatic cancer, and 28% lymph node or metastatic compression; metallic stent was placed in 92%. A total of 113 BI episodes occurred in 74 patients, 55% of the first episodes occurring within 3 months after stenting. BI was documented in 56% of the episodes. Enterobacteriaceae were the most frequent pathogens found, while no yeasts were documented. Mortality rate in patients with BI was 64%. Multivariate analysis showed a significant difference in BI occurrence for two criteria: WHO score 3-4 (OR=8.79 [1.79-42.89]; p=0.007) and transpapillary stenting location (OR=3.72 [1.33-10.44]; p=0.013).

CONCLUSION

Since transpapillary stenting is a risk factor for BI, preserving the papilla as much as possible is a priority so as to avoid BI.

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.

Design and Optimization of a New Anti-reflux Biliary Stent With Retractable Bionic Valve Based on Fluid-Structure Interaction Analysis

Duodenal biliary reflux has been a challenging common problem which could cause dreadful complications after biliary stent implantation. A novel anti-reflux biliary stent with a retractable bionic valve was proposed according to the concertina motion characteristics of annelids. A 2D equivalent fluid-structure interaction (FSI) model based on the axial section was established to analyze and evaluate the mechanical performances of the anti-reflux biliary stent. Based on this model, four key parameters (initial shear modulus of material, thickness, pitch, and width) were selected to investigate the influence of design parameters on anti-reflux performance via an orthogonal design to optimize the stent. The results of FSI analysis showed that the retrograde closure ratio of the retractable valve primarily depended on initial shear modulus of material (p < 0.05) but not mainly depended on the thickness, pitch, and width of the valve (p > 0.05). The optimal structure of the valve was finally proposed with a high retrograde closing ratio of 95.89%. The finite element model revealed that the optimized anti-reflux stent possessed improved radial mechanical performance and nearly equal flexibility compared with the ordinary stent without a valve. Both the FSI model and experimental measurement indicated that the newly designed stent had superior anti-reflux performance, effectively preventing the duodenobiliary reflux while enabling the bile to pass smoothly. In addition, the developed 2D equivalent FSI model provides tremendous significance for resolving the fluid-structure coupled problem of evolution solid with large deformation and markedly shortens the calculation time.

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.

Possible reasons for the regrettable results of patency of an inside stent in endoscopic transpapillary biliary stenting

Endoscopic biliary decompression is a minimally invasive procedure for cholestasis since the first endoscopic retrograde cholangiopancreatography-guided biliary stenting performed by Soehendra and Reynders-Frederix. Among the endoscopic biliary decompression, endoscopic transpapillary biliary stenting (EBS), is a mainstream choice and presently has two methods of placement: stenting above the sphincter of Oddi (SO) (suprapapillary) and stenting across the SO (transpapillary). Stent patency is the most important concern for patients, endoscopists and physicians because it can affect both the life prognosis and treatment schedule of patients. Biliary stent occlusion can occur because of several factors. Among them, direct food impaction, biofilm formation, and sludge formation play important roles and are presumed to be theoretically overcome by EBS above the SO. Thus, EBS above the SO is expected to result in a longer patency than EBS across the SO. In the literature, there have been six comparative studies on EBS for distal biliary obstruction in which the stent was placed above or across the SO, including two randomized controlled trials (RCTs) with negative results of stenting above the SO. With respect to EBS for hilar biliary obstruction, there have been no RCTs, whereas four retrospective comparative studies with negative results and four retrospective comparative studies showing positive results of stenting above the SO have been reported. In this review, we focused on EBS above and across the SO, and summarized the positive and negative results of the two types of stenting to promote effective clinical practice and to provide a basis for future studies.

Modified non-flared fully covered self-expandable metal stent for preoperative biliary drainage in pancreatic cancer

BACKGROUND AND AIM

Durable biliary drainage is essential in patients with pancreatic cancer in the era of effective neoadjuvant chemotherapy (NACT). Plastic stent (PS) tends to occlude easily, and current metal stents are designed for nonresectable cancer. We evaluated the efficacy of a modified non-flared fully covered self-expandable metal stent (M-FCSEMS) during the perioperative period in patients with resectable or borderline resectable pancreatic cancer.

METHODS

Consecutive patients with resectable or borderline resectable pancreatic ductal adenocarcinoma had a 12-mm M-FCSEMS (M-FCSEMS group) or 7-Fr PS (PS group) placed for biliary decompression before NACT or curative-intent surgery. The primary outcome was the re-intervention rate, and secondary outcomes were technical success, stent patency, and adverse events (AEs).

RESULTS

Endoscopic stent placement was technically successful in all 60 patients. Twenty-three patients underwent surgery and 37 NACT before surgery. Re-intervention was performed in 10.0% (3/30) of patients in the M-FCSEMS group and 36.7% (11/30) of patients in the PS group (P = 0.030). The stent patency at 180 days was 89.8% (95% confidence interval, 77.3-100.0%) in the M-FCSEMS group and 30.2% (95% confidence interval, 11.4-80.0%) in the PS group (P < 0.0001). Stent-related AEs occurred in 10.0% (3/30) in the M-FCSEMS group and 40.0% (12/30) in the PS group (P = 0.015). Surgery-related AEs occurred in 10.5% (2/19) and 14.3% (3/21) in the M-FCSEMS and PS groups (P = 0.549).

CONCLUSIONS

Modified non-flared fully covered self-expandable metal stents are effective and safe for durable biliary drainage in patients with resectable or borderline resectable pancreatic cancer during the perioperative period.

Metallic stent placement versus catheter drainage for malignant bilioenteric anastomotic stricture

PURPOSE

The purpose of the study was to compare self-expandable metallic stent placement with catheter drainage for malignant bilioenteric anastomotic stricture in terms of efficacy and safety.

MATERIALS AND METHODS

This study included 54 patients with malignant bilioenteric anastomotic stricture treated from March 2016 to February 2021. Twenty-seven patients underwent insertion of self-expandable metallic stent (Stent group); the remaining twenty-seven patients underwent internal-external catheter drainage (Catheter group). Technical success was defined as successful placement of stent or drainage catheter in the appropriate position; clinical success was defined as a 20% reduction in serum bilirubin within 1 week after the procedure, compared with baseline. Complications, duration to stent/catheter malfunction, and overall survival were evaluated.

RESULTS

Technical success was achieved in all patients in both groups. In the Stent group, 21 patients received one stent and the other 6 patients required two stents. Clinical success rates were similar between the groups [Stent group, 92.6% (25/27); Catheter group, 88.9% (24/27)]. There were no major complications. The median duration to stent/catheter malfunction was significantly longer in the Stent group (130 days) than in the Catheter group (82 days; P = 0.010). The median overall survival was also significantly longer in the Stent group (187 days) than in the Catheter group (118 days; P = 0.038).

CONCLUSION

Self-expandable metallic stent placement might be better than internal-external catheter drainage for malignant bilioenteric anastomotic stricture in terms of the duration before stent/catheter malfunction and patient survival.

Risk Factors of Duodenobiliary Reflux-Related Dysfunction of Covered Biliary Metal Stents after Treatment of Duodenal Stricture in Patients with Malignant Biliary and Duodenal Obstruction

Duodenal obstruction is often accompanied with unresectable malignant distal biliary obstruction in patients who have undergone biliary self-expandable metal stent (SEMS) placement. Duodenobiliary reflux (DBR) is a major cause of recurrent biliary obstruction (RBO) after covered biliary SEMS placement. We analyzed the risk factors for DBR-related SEMS dysfunction following treatment for malignant duodenal obstruction. Sixty-one patients with covered SEMS who underwent treatment for duodenal obstruction were included. We excluded patients with tumor-related stent dysfunction (n = 6) or metal stent migration (n = 1). Fifty-four patients who underwent covered biliary SEMS placement followed by duodenal metal stenting or surgical gastrojejunostomy were included. Eleven patients had DBR-related biliary SEMS dysfunction after treatment of duodenal obstruction. There was no difference between the duodenal metal stenting group and the surgical gastrojejunostomy group. Duodenal obstruction below the papilla of Vater and a score of ≤2 on the Gastric Outlet Obstruction Scoring System after treatment for duodenal obstruction were associated with DBR-related covered biliary SEMS dysfunction. Thus, creating a reliable route for ensuring good oral intake and avoiding DBR in patients with duodenal obstruction below the papilla of Vater are both important factors in preventing DBR-related covered biliary SEMS dysfunction.

Controversial issues of biliary stenting in patients with proximal biliary obstruction

The management of biliary decompression in malignant hilar carcinoma remains controversial. This review shows the most relevant aspects of endoprosthetics for proximal biliary obstruction, including necessity of stenting and morphological verification before radical surgery, selection of approach to drain etc. The main contradictions and ways to solve them are presented in this article, based on evidence researches, international and expert consensus conferences.

Feasibility of biliary stenting to distal malignant biliary obstruction using a novel designed metal stent with duckbill-shaped anti-reflux valve

OBJECTIVES

Anti-reflux metal stent (ARMS) has been used to prevent recurrent biliary obstruction (RBO) due to sludge formation or food impaction. However, the most suitable ARMS remains to be identified. This study aimed to evaluate the feasibility, safety, and efficacy of biliary drainage using duckbill-shaped ARMS (D-ARMS).

METHODS

This was a multicenter, retrospective observational study conducted at three Japanese tertiary institutions. Patients with distal malignant biliary obstruction who underwent biliary stenting using D-ARMS were eligible to participate. Technical success, functional success, adverse event (AE), and time to RBO (TRBO) were evaluated.

RESULTS

Thirty patients underwent biliary stenting using D-ARMS from December 2018 to October 2019. The technical success rate and functional success rate were 93% and 87%, respectively. However, nonvisibility of the markers at the tip of the metal stent or spontaneous extension was occasionally observed, making biliary stenting using D-ARMS difficult. Early AE occurred in 10% of the patients including cholangitis and pancreatitis. During the median postprocedural observation time of 5.1 months (range, 0.8-22.8), RBO occurred in 33% and the median TRBO was 261 days. As for reintervention, D-ARMS could be extracted in 67% of the patients with RBO. However, the stent was torn off on removal in half of the patients.

CONCLUSIONS

Although some modifications are still needed, D-ARMS was feasible and safe for biliary drainage, and sufficient TRBO was achieved. Subsequent multi-institutional studies involving a larger number of patients and a longer follow-up period are warranted to validate the present results.

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.

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.

Intraductal placement of a fully covered metal stent with a long string for distal malignant biliary obstruction without endoscopic sphincterotomy: Prospective multi-center feasibility study

BACKGROUND

Stent migration and sludge clogging are characteristic problems in biliary covered self-expandable metal stent (SEMS) placement. Intraductal placement without endoscopic sphincterotomy (ES) may help reduce their occurrence. We examined the feasibility of intraductal placement of a covered SEMS with a long string without ES in patients with unresectable distal malignant biliary obstruction (MBO).

METHODS

This was a prospective multi-center observational study. Forty patients with distal MBO were enrolled between July 2016 and August 2018. We evaluated recurrent biliary obstruction (RBO), adverse events other than RBO, and reintervention associated with intraductal placement without ES.

RESULTS

Both technical and functional success rates were 100% (40/40). The rate of adverse events other than RBO was 5% (2/40). The RBO rate was 33% (13/40), and the median time to RBO was 339 days. RBO was mainly caused by overgrowth on the papillary side, occurring in six patients; all such patients had pancreatic cancer and a distance between the papilla and the stricture of ≤20 mm. Other causes were overgrowth at the hepatic side in two patients and sludge in five patients. No instances of stent migration occurred. Success rates of endoscopic transpapillary reintervention and stent removal using the string were 92% (12/13) and 77% (10/13), respectively.

CONCLUSIONS

Intraductal placement without ES using a long-stringed covered SEMS is a promising option for distal MBO. Since overgrowth on the papillary side is frequent, the procedure should be avoided in patients with short distances between the stricture and the papilla. (Clinical Trial Registry: UMIN000023370).

Self-expandable metallic stent placement above the papilla without endoscopic sphincterotomy in patients with distal malignant biliary obstruction

Background and study aims  The best method for endoscopic placement of self-expandable metallic stents (SEMS) for distal malignant biliary obstruction (MBO) has not yet been determined. The aim of this study was to evaluate how SEMS placement above the papilla and without endoscopic sphincterotomy (EST) impacts the time to recurrent biliary obstruction (RBO) in patients with distal MBO. Patients and methods  We retrospectively reviewed data for 73 consecutive patients with unresectable distal MBO who underwent endoscopic SEMS placement for the first time at our institution between April 2014 and March 2016. We compared time to RBO of SEMS placement above the papilla (intraductal placement) with SEMS placement across the papilla (transpapillary placement). In the intraductal placement group, we also compared time to RBO of placement without EST with placement with EST. Results  Endoscopic SEMS placement was performed in 30 patients with intraductal placement and in 43 patients with transpapillary placement. The median time to RBO was significantly longer with intraductal placement (307 days) than with transpapillary placement (161 days) ( P  = 0.022). Complication rates did not differ between the two groups. In both univariate and multivariate analysis, intraductal placement was an independent factor contributing to prolonged time to RBO. In intraductal placement, time to RBO was significantly longer in SEMS placement without EST than with EST (363 days vs. 227 days, respectively; P  = 0.026). Conclusions  Intraductal SEMS placement, especially without EST for distal MBO contributed to longer time to RBO.

Pancreatitis and Biliary Obstruction Secondary to Duodenal Metastasis from Rapidly Progressing Lung Adenocarcinoma Treated with Common Bile Duct Stenting

Non-small cell lung cancer (NSCLC) is characterised by diffuse metastases, with common sites being the brain, liver, bones, and adrenal glands. Small bowel metastasis from NSCLC is a rare phenomenon, particularly in patients with an adenocarcinoma histology. We report the case of a 56-year-old lung adenocarcinoma patient with a duodenal metastasis diagnosed on FDG/PET-CT and confirmed on duodenal biopsy. Although initially asymptomatic, he subsequently presented with obstructive jaundice secondary to rapid local disease progression at the duodenal metastasis, requiring endoscopic intervention for biliary drainage. He was commenced on single agent pembrolizumab, with disease response on subsequent follow-up. This case highlights a rare case of gastrointestinal metastasis from NSCLC requiring endoscopic intervention due to rapid progression of the disease at the site of metastasis.

Early malfunction of a biliary self-expandable metal stent with an antireflux valve: A case report

RATIONALE

Biliary drainage is essential to resolve jaundice in patients with malignant biliary obstruction. Recently, a biliary self-expandable metal stent (SEMS) with an antireflux valve was developed to prevent enteric-biliary reflux. Its antireflux valve was made of expanded polytetrafluoroethylene (ePTFE), a biostable and biocompatible material. Changes of the ePTFE membrane of medical devices are rarely reported in clinical practice.

PATIENT CONCERNS

A 59-year-old woman was admitted with a complaint of jaundice. Around 1 month before, she underwent endoscopic biliary stenting using a SEMS with an antireflux valve.

DIAGNOSIS

Acute cholangitis due to stent clogging was detected on abdominal computed tomography.

INTERVENTIONS

Endoscopic retrograde cholangiopancreatography and removal of the SEMS with deformity were performed.

OUTCOMES

The obstructive jaundice was rapidly resolved after the removal of the clogged stent.

LESSONS

Although the ePTFE membrane is widely used to make medical devices, unexpected changes could occur after the membrane is exposed to bile juice in the duodenum. When performing biliary stenting using a SEMS with an antireflux valve, both the risk of early malfunction and the benefit of the antireflux effect should be considered.

Comparison of the Clinical Outcomes of Suprapapillary and Transpapillary Stent Insertion in Unresectable Cholangiocarcinoma with Biliary Obstruction

BACKGROUND AND AIMS

To prevent stent migration, transpapillary stent placement has been recommended for the endoscopic treatment of malignant hilar biliary stricture. However, recent studies have suggested that placement above the papilla achieves better results, because it is believed to prevent reflux and prolong stent patency. The aim of this study was to compare the efficacy and safety aspects of transpapillary and suprapapillary stent placement. In addition, the success rates of stent revision were evaluated.

MATERIALS AND METHODS

The medical records of 73 patients with hilar cholangiocarcinoma who underwent endoscopic metal stent insertion between January 2005 and December 2015 were retrospectively reviewed. Patients were assigned by stent location to a suprapapillary (S group; N = 44) or a transpapillary (T group; N = 29) cohort. Clinical outcomes, stent patency, adverse events, and revision success rates were compared between the two study groups.

RESULTS

Patency periods were similar in the two groups (S; 140 vs. T; 157 days; P = 0.732). Rates of stent obstruction in the S and T groups were 63.4% and 55.2%, respectively (P = 0.470). An adverse event occurred in 15 (20.5%) of total study subjects, with no significant intergroup difference. The endoscopic revision success rate was significantly higher in the T group (P = 0.01), and the time required for revision tended to be shorter in the T group.

CONCLUSIONS

The effectiveness and safety of suprapapillary and transpapillary stent insertion were found to be similar, but the success rate of endoscopic revision was significantly higher for the T group. Therefore, we recommend that transpapillary stent placement be considered for patients with hilar cholangiocarcinoma and biliary obstruction.

Percutaneous transpapillary biliary stent placement for distal malignant biliary obstruction: Outcomes and survival analysis

BACKGROUND/AIMS

For distal malignant biliary obstruction (MBO), a percutaneous metal stent is usually inserted by the transpapillary method. However, stent-related complications and recurrent biliary obstruction following transpapillary stent placement are concerns, and survival analysis of patients with distal MBO has rarely been done.

MATERIALS AND METHODS

From January 2012 to March 2016, 104 patients underwent transpapillary uncovered metal stent placement for distal MBO at our institution. Clinical success, complications, recurrent biliary obstruction rates, and predictors of survival were analyzed.

RESULTS

Of the total 104 patients, clinical success after stent insertion was achieved in 93 patients (90.3%). Major complications were observed in 24 patients (23.1%), which were as follows: cholangitis in 19 patients; pancreatitis in four patients; and biloma in one patient. Recurrent biliary occlusion was observed in 28 patients (26.9%). The median overall survival period was 162 days. The 3-, 6-, and 12-month overall survival rates after stent insertion were 64.4%, 41.3%, and 10.6%, respectively. Results of multivariate analysis indicated that metastatic carcinoma compared with ampullary carcinoma (HR=3.82; 95% CI, 1.30-11.24; p=0.015) and longer biliary stricture (HR=1.04; 95% CI, 1.02-1.06; p<0.001) were independent risk factors for worse survival after metal stent insertion.

CONCLUSION

Transpapillary stent placement was found to be effective with acceptable complication rates for treating distal MBO. Primary tumor and length of biliary stricture were found to be statistically significant independent prognostic factors for survival.

Antireflux valve metal stent versus conventional self-expandable metal stent in distal malignant biliary obstruction: a systematic review and meta-analysis

Background:

In patients with distal malignant biliary obstruction (MBO), endoscopic biliary drainage using the conventional self-expandable metal stent (SEMS) is the gold standard method for palliative treatment. However, there are limited data on the role of the antireflux valve metal stent (ARVMS). The aim of this study was to compare the safety and efficacy of ARVMS and SEMS in patients with distal MBO.

Methods:

We searched PubMed, Ovid, Embase and the Cochrane Library from inception until April 2019 for relevant randomized controlled trials (RCTs). The selected studies provided data regarding technical and clinical success rates, adverse events, and stent dysfunction. Data were meta-analyzed using RevMan software.

Results:

Three RCTs were selected, enrolling 293 patients (147 ARVMS and 146 SEMS). The rates of technical success were 95.23% and 99.31% for ARVMS and SEMS groups, respectively (odds ratio [OR] 0.13, 95% confidence interval [CI] 0.01-1.06; P=0.06). The clinical success rates were 91.57% and 89.36% for ARVMS and SEMS groups, respectively (OR 1.30, 95%CI 0.48-3.51; P=0.61). There was no significant difference between the ARVMS and SEMS groups in terms of adverse events (OR 0.61, 95%CI 0.35-1.05; P=0.07) or stent dysfunction (OR 0.77, 95%CI 0.31-1.95; P=0.58), while the incidence of stent occlusion was significantly lower in the ARVMS group (OR 0.44, 95%CI 0.26-0.76; P=0.003).

Conclusion:

Our study showed that ARVMS and SEMS had similar technical and clinical success rates. Adverse events were comparable between the 2 arms; however, ARVMS was associated with a lower risk of stent occlusion. Larger RCTs are required to verify the benefit of ARVMS in distal MBO patients.

Antireflux covered metal stent for nonresectable distal malignant biliary obstruction: Multicenter randomized controlled trial

BACKGROUND AND AIM

An antireflux metal stent (ARMS) for nonresectable distal malignant biliary obstruction (MBO) may prevent recurrent biliary obstruction (RBO) as a result of duodenobiliary reflux and prolong time to RBO (TRBO). Superiority of ARMS over conventional covered self-expandable metal stents (SEMS) has not been fully examined.

METHODS

We conducted a multicenter randomized controlled trial to examine whether TRBO of an ARMS with a funnel-shaped valve was longer than that of a covered SEMS in SEMS-naïve patients. We enrolled 104 patients (52 patients per arm) at 11 hospitals in Japan. Secondary outcomes included causes of RBO, adverse events, and patient survival.

RESULTS

TRBO did not differ significantly between the ARMS and covered SEMS groups (median, 251 vs 351 days, respectively; P = 0.11). RBO as a result of biliary sludge or food impaction was observed in 13% and 9.8% of patients who received an ARMS and covered SEMS, respectively (P = 0.83). ARMS was associated with a higher rate of stent migration compared with the covered SEMS (31% vs 12%, P = 0.038). Overall rates of adverse events were 20% and 18% in the ARMS and covered SEMS groups, respectively (P = 0.97). No significant between-group difference in patient survival was observed (P = 0.26).

CONCLUSIONS

The current ARMS was not associated with longer TRBO compared with the covered SEMS. Modifications including addition of an anti-migration system are required to use the current ARMS as first-line palliative treatment of distal MBO (UMIN-CTR clinical trial registration number: UMIN000014784).

Antireflux Metal Stent for Initial Treatment of Malignant Distal Biliary Obstruction

Objectives

To compare the use of an antireflux metal stent (ARMS) with that of a conventional covered self-expandable metal stent (c-CSEMS) for initial stenting of malignant distal biliary obstruction (MDBO).

Materials and Methods

We retrospectively investigated 59 consecutive patients with unresectable MDBO undergoing initial endoscopic biliary drainage. ARMS was used in 32 patients and c-CSEMS in 27. Technical success, functional success, complications, causes of recurrent biliary obstruction (RBO), time to RBO (TRBO), and reintervention were compared between the groups.

Results

Stent placement was technically successful in all patients. There were no significant intergroup differences in functional success (ARMS [96.9%] versus c-CSEMS [96.2%]), complications (6.2 versus 7.4%), and RBO (48.4 versus 42.3%). Food impaction was significantly less frequent for ARMS than for c-CSEMS (P = 0.037), but TRBO did not differ significantly between the groups (log-rank test, P = 0.967). The median TRBO was 180.0 [interquartile range (IQR), 114.0–349.0] days for ARMS and 137.0 [IQR, 87.0–442.0] days for c-CSEMS. In both groups, reintervention for RBO was successfully completed in all patients thus treated.

Conclusion

ARMS offers no advantage for initial stent placement, but food impaction is significantly prevented by the antireflux valve.

Differences in efficacy of uncovered self-expandable metal stent in relation to placement in the management of malignant distal biliary obstruction

BACKGROUND/AIMS

Metal stent insertion is a common palliative treatment for distal malignant biliary obstruction (MBO) but whether placement across the sphincter of Oddi (SO) causes more complications or shorter survival is in question. The aim of this study was to compare the clinical outcomes of percutaneous uncovered self-expandable metal stent placement above and across the SO in patients with distal MBO.

PATIENTS AND METHODS

We retrospectively studied 59 patients who underwent uncovered metal stent placement for distal MBO between January 2012 and March 2016. Stents were placed above the SO for 22 subjects (group A) and across the SO for 37 subjects (group B). Early cholangitis, stent occlusion, and overall survival time were compared between the two groups.

RESULTS

Clinical success was 90.9 and 86.5% for groups A and B, respectively. Early cholangitis occurred in 2 patients (9.1%) in group A and in 6 patients (16.2%) in group B (P = 0.645). Median stent patency and median survival time was 105 and 140 days for group A, 120 and 160 days for group B, respectively. The stent occlusion (31.8% in group A and 21.6% in group B, P = 0.454) and the cumulative stent patency times (P = 0.886) did not differ between the two groups. There was no significant difference in cumulative patient survival between the two groups (P = 0.810).

CONCLUSION

Uncovered metal stent placement across the SO did not significantly affect early cholangitis, stent patency, or patient survival.

Palliative Percutaneous Biliary Interventions in Malignant High Bile Duct Obstruction

The optimal palliative intervention for malignant biliary obstruction is internal drainage by placement of a metallic stent. For patients with hilar biliary obstruction or low bile duct obstruction in whom endoscopy is not feasible, a percutaneous transhepatic approach in interventional radiology is preferred. This article reviews the rationale for this approach, periprocedural management, and techniques to optimize stent patency.

Long-term outcomes and risk factors of biliary stent dysfunction after endoscopic double stenting for malignant biliary and duodenal obstructions

BACKGROUND AND AIM

Few reports describe the endoscopic double-stenting procedure for malignant biliary and duodenal obstructions. We evaluated the clinical outcomes from double stenting, and analyzed the risk factors for biliary stent dysfunction following double stenting.

METHODS

Eighty-one patients who underwent endoscopic double stenting for malignant biliary and duodenal obstructions were retrospectively analyzed. We determined the stent dysfunction rate and the biliary stent dysfunction risk factors, and analyzed the endoscopic reintervention results.

RESULTS

Overall survival time and survival time following double stenting were 365 (38-1673) days and 73 (20-954) days, respectively. After double stenting, the 3-month and 6-month duodenal stent dysfunction rates were 14% and 41%, respectively. Reintervention technical success rate was 100% (10/10), and mean gastric outlet obstruction scoring system scores improved from 0.7 to 2.4 points (P < 0.001). The 3-month and 6-month biliary stent dysfunction rates were 26% and 41%, respectively. The reintervention technical and clinical success rates were 95% (20/21) and 81% (17/21), respectively. Risk factors for biliary stent dysfunction following double stenting were events associated with duodenal stent dysfunction (odds ratio [OR], 11.1; 95% confidence interval [CI], 2.09-87.4; P = 0.0044) and the biliary stent end's location (OR, 6.93; 95% CI, 1.37-40.2; P = 0.0019).

CONCLUSIONS

Some patients had stent dysfunction irrespective of the survival period after double stenting. Endoscopic reintervention was technically feasible and clinically effective even after double stenting. Duodenal stent dysfunction and biliary stent end's location were risk factors for biliary stent dysfunction.

Antireflux Metal Stent as a First-Line Metal Stent for Distal Malignant Biliary Obstruction: A Pilot Study

BACKGROUND/AIMS

In distal malignant biliary obstruction, an antireflux metal stent (ARMS) with a funnel-shaped valve is effective as a reintervention for metal stent occlusion caused by reflux. This study sought to evaluate the feasibility of this ARMS as a first-line metal stent.

METHODS

Patients with nonresectable distal malignant biliary obstruction were identified between April and December 2014 at three Japanese tertiary centers. We retrospectively evaluated recurrent biliary obstruction and adverse events after ARMS placement.

RESULTS

In total, 20 consecutive patients were included. The most common cause of biliary obstruction was pancreatic cancer (75%). Overall, recurrent biliary obstruction was observed in seven patients (35%), with a median time to recurrent biliary obstruction of 246 days (range, 11 to 246 days). Stent occlusion occurred in five patients (25%), the causes of which were sludge and food impaction in three and two patients, respectively. Stent migration occurred in two patients (10%). The rate of adverse events associated with ARMS was 25%: pancreatitis occurred in three patients, cholecystitis in one and liver abscess in one. No patients experienced nonocclusion cholangitis.

CONCLUSIONS

The ARMS as a first-line biliary drainage procedure was feasible. Because the ARMS did not fully prevent stent dysfunction due to reflux, further investigation is warranted.

Stent placement above the sphincter of Oddi permits implementation of neoadjuvant chemotherapy in patients with initially unresectable Klatskin tumor

BACKGROUND AND STUDY AIMS

Neoadjuvant chemotherapy (NAC) may lead to a successful margin-negative resection in patients with initially unresectable locally advanced Klatskin tumor (IULAKT). Use of removable plastic stents is preferable for the safe implementation of NAC in patients with IULAKT to reduce the risk of recurrent cholangitis. Our aim was to evaluate the efficacy associated with the use of plastic stents placed across the stenosis and above the papilla (above stent) during NAC.

PATIENTS AND METHODS

In this study, we stratified the patients into two groups chronologically with respect to the period of stent placement: above stent group (n = 17) and across stent group (n = 23) (plastic stent across the sphincter of Oddi).

RESULTS

The median stent patency period was 99 days in the above stent group and 31 days in the across stent group (P < 0.0001). The number of stents (P = 0.017) and the rate of emerging undrained cholangitis areas (P = 0.025) were significantly reduced in the above stent group than the counterpart. Regarding time to recurrent biliary obstruction, the above stent group had a longer duration than the across stent group (log rank test, P = 0.004). Length of hospital stay was significantly shorter for the above stent group than the across stent group (P = 0.0475). Multivariate analysis revealed that above stent placement (odds ratio = 33.638, P = 0.0048) was significantly associated with stent patency over a period of 90 days.

CONCLUSIONS

Above stent placement should be considered for the relief of biliary obstruction and potentially reduces the cost for patients with IULAKT scheduled to receive NAC.

Stenting in Malignant Biliary Obstruction

Decompression of the biliary system in patients with malignant biliary obstruction has been widely accepted and implemented as part of the care. Despite a wealth of literature, there remains a significant amount of uncertainty as to which approach would be most appropriate in different clinical settings. This review covers stenting of the biliary system in cases of resectable or palliative malignant biliary obstruction, potential candidates for biliary drainage, technical aspects of the procedure, as well as management of biliary stent dysfunction. Furthermore, periprocedural considerations including proper mapping of the location of obstruction and the use of antibiotics are addressed.

Antireflux metal stent with an antimigration system for distal malignant biliary obstruction: a feasibility pilot study

An antireflux metal stent (ARMS) for distal malignant biliary obstruction has been reported to be useful, but the effectiveness of a flared-end structure to prevent migration on ARMS remains unclear. To evaluate the feasibility of a newly designed ARMS with both ends flared, 8 patients with covered metal stent occlusion due to sludge or food impaction were enrolled. ARMS were placed successfully after endoscopic removal of the occluded stents in all patients, and no procedure-related complication was observed. The median time to recurrent biliary obstruction was 71 days. ARMS occlusion occurred in 3 (38%) patients (sludge in 2 patients and hemobilia in 1). ARMS migration occurred in 1 (13%) patient. As a late complication, cholecystitis occurred in 1 (13%) patient. In conclusion, our newly designed ARMS with an antimigration system was technically feasible and safe, and a further investigation is warranted to evaluate the effectiveness of the current antimigration system.

A unique use of a double-pigtail plastic stent: correction of kinking of the common bile duct due to a metal stent

A 72-year-old man with jaundice by ampullary adenocarci-noma was treated at our hospital. For biliary decompression, a transpapillary, fully covered, self-expandable metal stent (FCSEMS) was deployed. Four days later, the patient devel-oped acute cholangitis. Endoscopic carbon dioxide cholan-giography revealed kinking of the common bile duct above the proximal end of the FCSEMS. A 7-F double-pigtail plastic stent was therefore placed through the FCSEMS to correct the kink, straightening the common bile duct (CBD) and im-proving cholangitis. This is the first report of a unique use of a double-pigtail plastic stent to correct CBD kinking. The place-ment of a double-pigtail plastic stent can correct CBD kink-ing, without requiring replacement or addition of a FCSEMS, and can lead to cost savings.

Suprapapillary versus transpapillary stent placement for malignant biliary obstruction: which is better?

PURPOSE

To compare the complications, stent patency, and patient survival with self-expandable metal stents (SEMSs) placed above or across the sphincter of Oddi in malignant biliary obstruction.

MATERIALS AND METHODS

From January 2008 to December 2012, 155 patients were treated with percutaneous transhepatic SEMS placement. Seventy-four patients underwent suprapapillary stent placement (group A), and 81 patients underwent transpapillary stent placement (group B). Complications rates, stent patency, and patient survival were evaluated and analyzed for potential predictors.

RESULTS

In group A, 68 covered and 28 uncovered SEMSs were placed, and, in group B, 78 covered and 19 uncovered SEMSs were placed. Thirty-six stent-related early complications were observed in a total of 154 patients (23.4%): pancreatitis (n = 23), cholangitis (n = 12), and cholecystitis (n = 1). The early complication rates for groups A and B were 14.9% (11 of 74) and 31.3% (25 of 80), respectively (P = .016). Pancreatitis occurred in three patients (4.1%) in group A and 20 patients (25.0%) in group B (P = .001). Stent location was a single independent predictor of pancreatitis (P < .001). Stent occlusions by tumor growth was more frequently observed in group A than in group B (P = .007), whereas stent occlusion by sludge incrustation was more frequently found in group B than in group A (P = .007). There was no significant difference in cumulative stent patency (P = .401) or patient survival (P = .792) between groups.

CONCLUSIONS

To decrease the incidence of pancreatitis, suprapapillary placement of SEMSs is recommended for malignant biliary obstruction, but not in the lower 2 cm of the common bile duct.

Comparison of uncovered stent placement across versus above the main duodenal papilla for malignant biliary obstruction

PURPOSE

To evaluate the differences in efficiency and complications of metal stent insertion across versus above the main duodenal papilla (MDP) in patients with malignant obstruction of the common bile duct (CBD).

MATERIALS AND METHODS

Records of 98 consecutive patients who underwent stent insertion for malignant CBD obstruction between 2004 and 2010 were retrospectively reviewed. Fifty-one patients (group 1) and 47 patients (group 2) were treated with stent insertion across and above the MDP, respectively. Primary stent patency, overall survival, complications, and changes in serum bilirubin level following stent insertion were assessed.

RESULTS

Infection appeared in 12 and four patients, respectively, in groups 1 and 2. The respective mean primary stent patency times were 307.8 days ± 20.2 and 490.7 days ± 40.7, and mean survival times were 245.1 days ± 17.4 and 286.3 days ± 20.2. Bilirubin reduction rates were 55.7% ± 16.6 and 61.1% ± 13.7 at 1 week and 84.2% ± 5.7 and 86.2% ± 5.7 at 1 month in groups 1 and 2, respectively. In group 2, the rate of infection was significantly lower (P = .044) and primary stent patency was longer (P = .019). However, there was no significant difference between groups in survival time (P = .074) or bilirubin reduction rate at 1 week (P = .083) or 1 month (P = .082).

CONCLUSIONS

Bile stent insertion above the MDP may achieve longer stent patency and a lower infection rate compared with placement across the MDP. For patients with malignant CBD obstruction, biliary stents should be placed above the papilla if papillary lesions are not invaded.

Safe and Successful Yttrium-90 Resin Microsphere Radioembolization in a Heavily Pretreated Patient with Chemorefractory Colorectal Liver Metastases after Biliary Stent Placement above the Papilla

We report a case of safe and successful yttrium-90 resin microsphere radioembolization in a patient with a long history of multiple recurrent colon cancer hepatic metastases progressing after hepatic resections, hepatic arterial chemotherapy, and multiple regimens of systemic chemotherapy. One month prior to radioembolization, a biliary stent was placed above the level of the ampulla to relieve tumor-related biliary obstruction and normalize bilirubin levels.