Pilot study of a novel, large-bore, fully covered self-expandable metallic stent for unresectable distal biliary malignancies

Potential of 6-mm-diameter fully covered self-expandable metal stents for unresectable malignant distal biliary obstruction: a propensity score-matched study

BACKGROUND/AIMS

To date, only thinner-diameter metal stents have been evaluated for unresectable malignant distal biliary obstruction (UR-MDBO). This study investigated the outcomes and optimal cohorts for a 6-mm-diameter fully covered self-expandable metal stent (FCSEMS) compared with those for a 10-mm-diameter FCSEMS.

METHODS

This single-center retrospective cohort study included patients who underwent initial transpapillary metal stenting for UR-MDBO. Propensity score matching (1:1) analysis was performed.

RESULTS

Of 133/68 patients who underwent 6-mm/10-mm-diameter FCSEMS deployment, 59 in each group were selected. The median time to recurrent biliary obstruction was not significantly different between the groups (p=0.46). In contrast, use of the 6-mm-diameter FCSEMS resulted in a significantly reduced incidence of stent-related adverse events (AEs) (p=0.016), especially cholecystitis (p=0.032), and patients aged <70 years were particularly affected by this significant reduction. Among the patients in the end-stage cohort who were unable to continue chemotherapy after FCSEMS deployment, the free rate of stent-related events, including recurrent biliary obstruction and stent-related AEs, was significantly higher in the 6-mm group (p=0.027).

CONCLUSIONS

For UR-MDBO, a 6-mm-diameter FCSEMS can be an optimal and safe option in the younger cohort with a relatively high risk of AEs and in the end-stage cohort requiring safer drainage without interference from stent-related events during times of poor prognosis.

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

BACKGROUND

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

METHODS

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

RESULTS AND CONCLUSIONS

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

Comparison of covered self-expandable metallic stents with 12-mm and 10-mm diameters for unresectable malignant distal biliary obstructions: a prospective randomized trial

BACKGROUND AND AIMS

Covered self-expandable metallic stents have longer patency than uncovered self-expandable metallic stents for unresectable malignant distal biliary obstruction because of the prevention of tumor ingrowth, and they are removable during reintervention. One main cause of recurrent biliary obstruction in covered self-expandable metallic stents is sludge formation, which can be prevented by using large-bore stents. We evaluated the treatment results of 12-mm and 10-mm covered self-expandable metallic stents for unresectable malignant distal biliary obstructions using a randomized controlled trial.

METHODS

This study was conducted between May 2016 and January 2019 and included 81 consecutive patients with unresectable malignant distal biliary obstruction. The primary endpoint was the rate of nonrecurrent biliary obstruction at 6 months after stent placement.

RESULTS

The primary endpoint in the 12-mm group was significantly higher than that in the 10-mm group (P = .0369). Therefore, the median time to recurrent biliary obstruction was 172 days in the 12-mm group and 120 days in the 10-mm group. The median time to recurrent biliary obstruction in the 12-mm group was significantly longer than that in the 10-mm group (P = .0168). Using the 12-mm covered self-expandable metallic stents and receiving chemotherapy were factors affecting the rate of recurrent biliary obstruction in the multivariate analysis.

CONCLUSIONS

The 12-mm covered self-expandable metallic stents provide a longer time to recurrent biliary obstruction than do 10-mm covered self-expandable metallic stents for managing unresectable malignant distal biliary obstruction. (Clinical trial registration number: UMIN000016911.).

Re-intervention with 10-mm vs 12-mm covered self-expandable metallic stent for recurrent unresectable distal biliary obstruction in patients with previous stent implantation

BACKGROUND

Treatment for unresectable distal malignant biliary obstruction (DMBO) involves placing a 10-mm covered self-expandable metallic stent (CSEMS). In recurrent biliary obstruction (RBO), replacement of the CSEMS is recommended; however, the appropriate stent type remains unknown. We speculated that large-bore CSEMSs would provide longer patency. We compared the efficacy of 10-mm and 12-mm CSEMS in patients with RBO.

METHODS

We retrospectively retrieved data on patients who underwent CSEMS replacement from the endoscopic database. We investigated the time to RBO (TRBO) after CSEMS replacement. The hazard ratio (HR) for the the second TRBO was estimated using the Cox proportional hazard model. The estimated median second TRBO was determined using the Kaplan-Meier method.

RESULTS

Among the 493 patients with DMBOs treated with 10-mm CSEMS, 48 and 29 patients underwent re-intervention with 10-mm and 12-mm CSEMS, respectively. The use of 12-mm CSEMS was inversely associated with second TRBO (multivariable-adjusted HR, 0.62; 95% CI, 0.39-0.98; P = .042). The estimated median second TRBO was greater with the 12 mm CSEMS than with the 10 mm variety (562 days vs 207 days; P = .019).

CONCLUSION

The second intervention with 12-mm CSEMS was associated with a longer TRBO.

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

BACKGROUND AND AIMS

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Comparison of 6-mm and 10-mm-diameter, fully-covered, self-expandable metallic stents for distal malignant biliary obstruction

Background and study aims For distal malignant biliary obstruction, self-expandable metallic stents (SEMSs) have a larger inner diameter compared to plastic stents, which prolongs time to recurrent biliary obstruction (TRBO), although stent-related complications are still a problem. This study aimed to compare the outcomes between using 10– and 6-mm-diameter fully-covered SEMS (FCSEMS) for distal malignant biliary obstruction.

Patients and methods This single-center, retrospective study included patients with 10-mm or 6-mm-diameter FCSEMS to treat distal malignant biliary obstruction. Clinical success, stent-related adverse events (AEs), cumulative incidence of RBO, factors involved in stent-related AEs, and factors involved in RBO were evaluated.

Results There were 243 eligible cases between October 2017 and December 2021. The cumulative incidence of RBO did not differ significantly between the 10-mm and 6-mm groups. Stent-related AEs occurred in 31.6 % and 11.4 % of patients between the 10-mm and 6-mm groups, respectively (P < 0.01). Pancreatitis occurred in 10.5 % and 3.6 % (P = 0.04) and cholecystitis occurred in 11.8 % and 3.0 % of patients (P = 0.03) in the 10-mm and 6-mm groups, respectively. In multivariate analysis, the 6-mm stent was extracted as a factor linked to a reduced risk of AEs, but not as a risk factor of RBO.

Conclusions The 6-mm-diameter FCSEMS for distal malignant biliary obstruction is a well-balanced stent with a cumulative incidence of RBO compatible to that of the 10-mm-diameter FCSEMS and fewer stent-related AEs.

Comparison of novel large-bore and conventional-bore covered self-expandable metal stents for malignant gastric outlet obstruction: Multicenter, retrospective study

OBJECTIVES

Covered self-expandable metal stent (cSEMS) for gastric outlet obstruction (GOO) has been developed to overcome tumor ingrowth but is prone to be associated with an increased risk of migration. Clinical impact of the novel large-bore cSEMS for malignant GOO remains unclear.

METHODS

A total of 117 patients undergoing endoscopic cSEMS placement for malignant GOO were enrolled in this multicenter retrospective study. Technical and clinical success, adverse events, recurrent GOO, and survival after stent placement were compared between 24 mm-cSEMS (n = 49) and 20 mm-cSEMS (n = 68).

RESULTS

Patient characteristics were well-balanced and thus similar survival was observed between the two groups (136 days vs. 89 days, P = 0.60). Technical success rate of 100% and clinical success rate of 96% were achieved both in 24 mm-cSEMS and 20 mm-cSEMS, respectively. The median cumulative time to recurrent GOO was significantly longer in 24 mm-cSEMS than in 20 mm-cSEMS (380 days vs. 138 days, P = 0.01). The incidence of adverse events and recurrent GOO was comparable: 12% vs. 15% (P = 0.91), and 16% vs. 31% (P = 0.11); however, no stent migration was observed in 24 mm-cSEMS. In a subgroup analysis, the superiority of 24 mm-cSEMS to 20 mm-cSEMS was demonstrated in extrinsic cancers (380 days vs. 121 days, P = 0.01) but not in intrinsic cancers (151 days vs. not reached, P = 0.47).

CONCLUSIONS

The 24 mm-cSEMS may improve time to recurrent GOO with ensuring acceptable safety in patients with malignant GOO.

Safety and Efficacy of Gemcitabine Plus Nab-Paclitaxel for Metastatic Pancreatic Cancer Patients Undergoing Biliary Stent Placement

BACKGROUND

Gemcitabine plus nab-paclitaxel (GnP) is the first-line chemotherapeutic regimen for metastatic pancreatic cancer (MPC); however, there are concerns regarding its safety in patients undergoing biliary stent placement. This study aimed to examine the tolerability and efficacy of GnP in MPC patients who underwent biliary stent placement.

METHODS

A total of 105 MPC patients who had received GnP treatment between 2015 and 2020 were included and investigated. The patients were divided into two groups: those undergoing biliary stent placement for symptomatic biliary obstruction (BO) (With-BO group) and those without biliary stent placement (Without-BO group). The best tumor response, overall survival (OS), and adverse events in each group were compared.

RESULTS

The partial response, stable disease, and progressive disease rates were 22%, 61%, and 14.6% in the With-BO group, and 26.6%, 46.9%, and 21.9% in the Without-BO group, respectively, with no significant differences. The median OS was 12.2 months and 14.6 months in the With-BO and Without-BO groups, respectively (P = 0.483). Grade 3 or higher biliary tract-related events were significantly more common in the With-BO group (41.5%) than in the Without-BO group (1.6%) (P < 0.001), but all events were managed successfully by urgent intervention. The rates of any treatment-related toxicities, including febrile neutropenia, were not significantly different, and there were no chemotherapy-related deaths in either group.

CONCLUSIONS

GnP can be as tolerable and effective in MPC patients with biliary stents as in those without biliary stents. However, careful management and appropriate reintervention to treat biliary tract-related adverse events are required.

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.

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.

Current Status of Endoscopic Biliary Drainage in Patients with Distal Malignant Biliary Obstruction

Distal malignant biliary obstruction is caused by various malignant diseases that require biliary drainage. In patients with operable situations, preoperative biliary drainage is required to control jaundice and cholangitis until surgery. In view of tract seeding, endoscopic biliary drainage is the first choice. Since neoadjuvant therapies are being developed, the time to surgery is increasing, especially in pancreatic cancer cases. Therefore, it requires long stent patency. Recently, preoperative biliary drainage using self-expandable metal stents has been reported as a useful modality to secure long stent patency. In patients with unresectable distal malignant biliary obstruction, self-expandable metal stent is the first choice for maintaining long stent patency. Although there are many comparison studies between a covered and an uncovered self-expandable metal stent, their use is still controversial. Recently, endoscopic ultrasound-guided biliary drainage has been performed as an alternative treatment. The clinical success and stent patency are favorable. We should take into consideration that both endoscopic retrograde cholangiopancreatography-guided biliary drainage and endoscopic ultrasound-guided biliary drainage have advantages and disadvantages and chose the drainage method depending on the patient’s situation or the expertise of the endoscopist. Here, we discuss the current status of endoscopic biliary drainage in patients with distal malignant biliary obstruction.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

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

BACKGROUND

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

AIMS

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

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.

Usefulness of newly modified fully covered metallic stent of 12 mm in diameter and anti-migration feature for periampullary malignant biliary strictures: Comparison with conventional standard metal stent

BACKGROUNDS

Fully covered self-expandable metal stent (FCSEMS) are preferred for distal malignant biliary stricture (MBS). However, stent migration is a major adverse event of FCSEMS, especially for far distal MBS. We evaluated the usefulness of newly modified FCSEMS (M-FCSEMS) having 12 mm in diameter and anti-migration feature to minimize stent migration compared with the conventional FCSEMS (C-FCSEMS).

METHODS

Total 102 patients were enrolled between January 2015 and September 2017 in this prospective comparative study; 50 were allocated to the M-FCSEMS group and 52 to the C-FCSEMS group. The primary outcome was stent migration, and the secondary outcomes were other adverse events, stent occlusion rate, and stent patency during the follow-up period.

RESULTS

The baseline characteristics of the two groups did not significantly differ. Endoscopic stent placement was technically successful in all patients. Stent migration occurred in 8.0% (4/50) of the patients in the M-FCSEMS group and 23.1% (12/52) of those in the C-FCSEMS group (P = 0.036). The other adverse events, including stent-related pancreatitis and cholecystitis did not significantly differ between the two groups (P = 0.415). Stent occlusion occurred in 23.9% (11/46) of the patients in the M-FCSEMS group and 37.5% (15/40) in the C-FCSEMS group (P = 0.171). Stent patency was significantly longer in the M-FCSEMS group than in the C-FCSEMS group (228 vs 157 days, P = 0.048).

CONCLUSIONS

Modified FCSEMS with 12-mm diameter and anti-migration feature significantly decreased the risk of stent migration and had longer patency compared with C-FCSEMS in patients with periampullary MBS.

Comparison of 8- and 10-mm diameter fully covered self-expandable metal stents: A multicenter prospective study in patients with distal malignant biliary obstruction

OBJECTIVES

The time to recurrent biliary obstruction (TRBO) of unresectable distal malignant biliary obstruction is generally thought to be longer when a self-expandable metal stent (SEMS) with a thicker inner diameter is used for drainage, but the dependence on the inner diameter using a fully covered SEMS (FCSEMS) is uncertain. The objective of this multicenter prospective study was to compare TRBO and adverse events, such as cholecystitis and pancreatitis, in treatment of patients with unresectable malignant biliary obstruction using 8- and 10-mm diameter FCSEMS.

METHODS

Eighteen tertiary-care centers participated in the study. Patients were allocated to the 8- and 10-mm diameter groups. TRBO, non-inferiority of the 8-mm FCSEMS, overall survival time, frequency and type of adverse events, and non-recurrent biliary obstruction (RBO) rate at the time of death were compared between the two groups.

RESULTS

Median TRBO did not differ significantly between the 8-mm (n = 102) and 10-mm (n = 100) groups (275 vs 293 days, P = 0.971). The hazard ratio of the 8- to 10-mm groups was 0.90 (80% confidence interval, 0.77-1.04; upper limit lower than the acceptable hazard ratio [1.33] of the null hypothesis). Based on these findings, the 8-mm diameter stent was determined to be non-inferior to the 10-mm diameter stent. Survival time, incidence of adverse events and non-RBO rate at the time of death did not differ significantly between the two groups.

CONCLUSIONS

Time to RBO with an 8-mm diameter FCSEMS was non-inferior to that with a 10-mm diameter FCSEMS. This finding is important for development of future SEMS.

Evaluation of a 12-mm diameter covered self-expandable end bare metal stent for malignant biliary obstruction

Background and study aims  Biliary metallic stents are used to drain unresectable malignant distal biliary obstructions. This study aimed to evaluate the efficacy of a novel 12-mm-diameter covered, self-expandable end bare metal stent (12-mm CSEEMS). Patients and methods  We evaluated 99 patients with unresectable malignant distal biliary obstructions treated with covered biliary metallic stents. Of the 99 patients, 33 underwent 12-mm CSEEMS placement between June 2015 and April 2017 (12-mm-CSEEMS group) and 66 underwent 10-mm fully-covered self-expandable metal stent (FCSEMS) placement between January 2010 and July 2015 (10-mm-FCSEMS group). The overall survival (OS), the recurrent biliary obstruction (RBO), cause of RBO, time to RBO (TRBO) and adverse events in 12-mm-CSEEMS group and 10-mm-FCSEMS group were evaluated retrospectively. Results  The OS tended to be longer in the 12-mm-CSEEMS group (log rank, P  = 0.081) and TRBO was significantly longer in the 12-mm-CSEEMS group (log rank, P  = 0.001) than in the 10-mm-FCSEMS group. Both univariate (HR, 0.449; 95 % CI, 0.27967 - 0.72215; P  = 0.001) and multivariate (HR, 0.458; 95 % CI, 0.28395 - 0.73744; P  = 0.001) Cox hazard analysis found that risk of RBO was significantly lower in 12-mm CSEEMS than in 10-mm FCSEMS. There were no significant differences between the 12-mm-CSEEMS group and 10-mm-FCSEMS group regarding the cause of RBO and adverse events. Conclusions  The 12-mm CSEEMS showed a low risk of RBO compared with 10-mm FCSEMS and was considered to be effective and safe for draining unresectable malignant distal biliary obstruction.

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.

New 14-mm diameter Niti-S biliary uncovered metal stent for unresectable distal biliary malignant obstruction

AIM

To investigate whether an uncovered self-expandable metal stent (UCSEMS) with a large diameter could prevent recurrent biliary obstruction (RBO).

METHODS

Thirty-eight patients with malignant biliary obstruction underwent treatment with an UCSEMS with a 14-mm diameter (Niti-S 14). Retrospectively, we evaluated technical and functional success rate, RBO rate, time to RBO, survival time, and adverse events in these patients.

RESULTS

Stent placement success and functional success were achieved in all patients. Two patients (5.3%) had RBO due to tumor ingrowth or overgrowth. The median time to RBO was 190 (range, 164-215) d. The median survival time was 120 (range, 18-502) d. The 6-mo non-RBO rate was 91%. Other adverse events other than RBO occurred as follows: Acute cholecystitis, post-ERCP pancreatitis, hemobilia, and fever without exacerbation of liver injury, and liver abscess in 4 (10.3%), 3 (7.9%), 2 (5.3%), 1 (2.6%), and 1 (2.6%), respectively. Migration of the stents was not observed.

CONCLUSION

Niti-S 14 is considered to be a preferable metal stent because of a low rate of RBO with no migration.

Endoscopic treatment for distal malignant biliary obstruction

Distal malignant biliary obstruction (MBO) leads to obstructive jaundice as a result of when the bile excretion from the liver is disturbed and induces hepatic failure and sepsis, which when complicated with cholangitis, it becomes necessary to perform drainage for the MBO. For biliary drainage, we can perform a surgical bypass operation, percutaneous transhepatic biliary drainage (PTBD), endoscopic biliary drainage (EBD) via duodenal papilla, or endoscopic ultrasound (EUS)-guided biliary drainage (EUS-BD), which is a transgastrointestinal biliary drainage. Although currently we usually perform EBD for distal MBO to begin with, the choice is different for biliary drainage in patients in whom EBD has failed in a preoperative case or an unresectable case. In other words, we choose PTBD for preoperative cases, and PTBD or EUS-BD according to the ability of the institution for their procedures when EBD has failed. It is desirable not to choose a plastic stent (PS) but a self-expandable metallic stent (SEMS), in particular for the unresectable cases of pancreatic cancer it is desirable not to choose an uncovered SEMS but a covered SEMS in EBD. Nevertheless, further examinations are expected to decide which, a covered or uncovered SEMS, we should choose in unresectable biliary tract cancer (BTC) and whether we should select PS, SEMS or ENBD in preoperative cases.