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

Practical guide to duodenal stenting for gastric outlet obstruction: Clinical outcomes, selection criteria, placement techniques, and management strategies

Duodenal stenting is a widely used palliative treatment for gastric outlet obstruction (GOO) caused by unresectable malignancies. Compared to surgical gastrojejunostomy, duodenal stenting allows for earlier oral intake, shorter hospitalization, and earlier chemotherapy initiation. However, its long-term efficacy is limited by stent occlusion, which typically occurs 2-4 months post-procedure, due to tumor ingrowth, overgrowth, or food impaction. Covered stents can reduce tumor ingrowth but increase the migration risk, particularly in patients receiving chemotherapy. This review provides a comprehensive comparison of duodenal stenting, surgical gastrojejunostomy, and endoscopic ultrasound-guided gastroenterostomy, by discussing their clinical outcomes, advantages, and limitations. We further explore stent selection based on stricture characteristics, optimal placement techniques, post-procedural management, and for handling complications including occlusion, migration, bleeding, and perforation. Additionally, we address technical challenges and troubleshooting strategies, including management of guidewire-induced perforation, incomplete stent expansion, and bile duct obstruction for overlapping biliary and duodenal stricture cases. Despite its widespread clinical use, no prior review has comprehensively covered both the technical and clinical aspects of duodenal stenting so extensively. By providing a clinically oriented, practical guide, this review serves as a valuable resource for endoscopists and gastroenterologists, facilitating optimized decision-making and improved outcomes for patients with GOO in real-world practice.

A multi-institutional study designed by members of Tokyo Guidelines (TG) Core Meeting to elucidate the clinical characteristics and pathogenesis of acute cholangitis after bilioenteric anastomosis and biliary stent insertion with a focus on biliary obstruction: Role of transient hepatic attenuation difference (THAD) and pneumobilia in improving TG diagnostic performance

BACKGROUND/PURPOSE

The aim of this study was to clarify the clinical characteristics of acute cholangitis (AC) after bilioenteric anastomosis and stent-related AC in a multi-institutional retrospective study, and validate the TG18 diagnostic performance for various type of cholangitis.

METHODS

We retrospectively reviewed 1079 AC patients during 2020, at 16 Tokyo Guidelines 18 (TG 18) Core Meeting institutions. Of these, the post-biliary reconstruction associated AC (PBR-AC), stent-associated AC (S-AC) and common AC (C-AC) were 228, 307, and 544, respectively. The characteristics of each AC were compared, and the TG18 diagnostic performance of each was evaluated.

RESULTS

The PBR-AC group showed significantly milder biliary stasis compared to the C-AC group. Using TG18 criteria, definitive diagnosis rate in the PBR-AC group was significantly lower than that in the C-AC group (59.6% vs. 79.6%, p < .001) because of significantly lower prevalence of TG 18 imaging findings and milder bile stasis. In the S-AC group, the bile stasis was also milder, but definitive-diagnostic rate was significantly higher (95.1%) compared to the C-AC group. The incidence of transient hepatic attenuation difference (THAD) and pneumobilia were more frequent in PBR-AC than that in C-AC. The definitive-diagnostic rate of PBR-AC (59.6%-78.1%) and total cohort (79.6%-85.3%) were significantly improved when newly adding these items to TG18 diagnostic imaging findings.

CONCLUSIONS

The diagnostic rate of PBR-AC using TG18 is low, but adding THAD and pneumobilia to TG imaging criteria may improve TG diagnostic performance.

Percutaneous insertion of long-covered biliary stents in patients with malignant duodenobiliary stricture

OBJECTIVE

To investigate the technical feasibility, safety, and efficacy of a long-covered biliary stent in patients with malignant duodenobiliary stricture.

METHODS

This retrospective study enrolled 57 consecutive patients (34 men, 23 women; mean age, 64 years; range, 32-85 years) who presented with malignant duodenobiliary stricture between February 2019 and November 2020. All patients were treated with a long (18 or 23 cm)-covered biliary stent.

RESULTS

The biliary stent deployment was technically successful in all 57 patients. The overall adverse event rate was 17.5% (10 of 57 patients). Successful internal drainage was achieved in 55 (96.5%) of 57 patients. The median patient survival and stent patency times were 99 days (95% confidence interval [CI], 58-140 days) and 73 days (95% CI, 60-86 days), respectively. Fourteen (25.5%) of the fifty-five patients presented with biliary stent dysfunction due to sludge (n = 11), tumor overgrowth (n = 1), collapse of the long biliary stent by a subsequently inserted additional duodenal stent (n = 1), or rapidly progressed duodenal cancer (n = 1). A univariate Cox proportional hazards model did not reveal any independent predictor of biliary stent patency.

CONCLUSIONS

Percutaneous insertion of a subsequent biliary stent was technically feasible after duodenal stent insertion. Percutaneous insertion of a long-covered biliary stent was safe and effective in patients with malignant duodenobiliary stricture.

CLINICAL RELEVANCE STATEMENT

In patients with malignant duodenobiliary stricture, percutaneous insertion of a long-covered biliary stent was safe and effective regardless of duodenal stent placement.

KEY POINTS

• Percutaneous insertion of long-covered biliary stents in patients with malignant duodenobiliary stricture is a safe and effective procedure. • Biliary stent deployment was technically successful in all 57 patients and successful internal drainage was achieved in 55 (96.5%) of 57 patients. • The median patient survival and stent patency times were 99 days and 73 days, respectively, after placement of a long-covered biliary stent in patients with duodenobiliary stricture.

Long-term outcomes of endoscopic double stenting using an anti-reflux metal stent for combined malignant biliary and duodenal obstruction

PURPOSE

To evaluate long-term outcomes of endoscopic double stenting using anti-reflux metal stents (ARMS) for combined malignant biliary and duodenal obstruction.

METHODS

Consecutive patients with advanced pancreatic cancer who received endoscopic double stenting with self-expandable metal stents (SEMS) for combined malignant biliary and duodenal obstruction at our institution between July 2014 and March 2021 were evaluated. Patients were divided into the ARMS group, endoscopic ultrasound-guided hepaticogastrostomy (EUS-HGS) group, and covered metal stent-transpapillary (CMS-transpapillary) group. A Duckbill-type metal stent was used in all ARMS cases.

RESULTS

Thirty-eight patients were enrolled: ARMS group (n = 16), EUS-HGS group (n = 13), and CMS-transpapillary group (n = 9). Overall survival among three groups were not significantly different. Recurrent biliary obstruction (RBO) rates of the ARMS, EUS-HGS, and CMS-transpapillary groups were 12.5%, 61.5%, and 88.9% (P < .01) and median time to recurrent biliary obstructions (TRBOs) were not reached, 125 days, and 7 days (P < .01). Median TRBOs of ARMS-choledochoduodenostomy and ARMS-transpapillary were not statistically different. Major causes of RBO were stent occlusion and symptomatic stent migration in the ARMS group, hyperplasia in the EUS-HGS group, and non-occlusion cholangitis in the CMS-transpapillary group.

CONCLUSIONS

Endoscopic double stenting with ARMS might be an option for combined malignant biliary and duodenal obstruction.

Comparison of Duodenal Stenting and Gastrojejunostomy for Duodenal Obstruction with Biliary Obstruction

BACKGROUND

The best palliation for double obstruction (duodenal obstruction with biliary obstruction) remains unclear. We aimed to compare outcomes of duodenal stenting (DuS) with gastrojejunostomy (GJ) and identify factors associated with survival time and time to recurrent biliary obstruction (TRBO).

METHODS

Patients who underwent DuS or GJ combined with biliary stenting for double obstruction due to unresectable malignancy were retrospectively enrolled.

RESULTS

In total, 111 patients were included; 84 underwent DuS, and 27 underwent GJ. The weighted survival time of the DuS group was significantly shorter than that of the GJ group (86 days vs 134 days, P < 0.01). Although the weighted TRBO was not significantly different between the two groups, when limited to patients with distal duodenal obstruction, the weighted TRBO was significantly longer in the DuS group than in the GJ group (207 days vs. 32 days, P < 0.01). GJ for distal duodenal obstruction was identified as the factor with the highest hazard ratio and was associated with a shorter TRBO (hazard ratio 8.5, P < 0.01).

CONCLUSIONS

Regarding survival time, GJ should be considered the primary treatment for patients with double obstruction. However, for patients with distal duodenal obstruction, DuS should be considered because GJ may be a risk factor for a shorter TRBO.

How to successfully administer palliative treatment with a stent for malignant gastric outlet obstruction?

Although endoscopic stenting (ES) has been widely used as a less-invasive palliation method for malignant gastric outlet obstruction (GOO), recent reports have highlighted issues related to the procedure. For successful treatment, various aspects must be assessed before considering the practices. First, it is necessary to eliminate cases with contraindications such as coexistence of distal small-bowel obstruction or perforation. Other factors potentially related to clinical failure (i.e., peritoneal carcinomatosis) may require consideration but remain controversial. ES has better short-term outcomes than surgical gastrojejunostomy (GJ). GJ has recently been considered preferable in cases with longer life expectancy because of superior sustainability. Various types of stents are now commercially available, but their ideal structure and mechanical properties have not yet been clarified. Covered metal stent may reduce stent obstruction but is prone to increase stent migration, and its significance remains uncertain. Subsequent chemotherapy after stenting should be considered, as it is expected to prolong patient survival without increasing the risk of adverse events. Furthermore, it may be helpful in preventing tumor ingrowth. In cases with GOO combined with biliary obstruction, biliary intervention is often difficult. Recently, endoscopic ultrasound-guided biliary drainage (EUS-BD) has been widely used as an alternative procedure for endoscopic transpapillary biliary drainage (ETBD). Despite the lack of consensus as to whether ETBD or EUS-BD is preferred, EUS-BD is useful as a salvage technique for cases where ETBD is difficult. To perform stent placement successfully, it is important to pay attention to the above points; however, many remaining issues need to be clarified in the future.

Endoscopic stenting for malignant biliary obstruction is technically successful in patients with preexisting duodenal stents

Background and study aims  There are limited data on the success of endoscopic retrograde cholangiopancreatography (ERCP) in patients with malignant biliary and duodenal obstruction with a preexisting duodenal stent. The aim of this study was to evaluate patient and procedural outcomes of a cohort of patients with preexisting duodenal stents who underwent an attempt at ERCP for malignant biliary obstruction (MBO). Patients and methods  This was a single-center retrospective study on consecutive patients with a preexisting duodenal stent who underwent attempted ERCP for MBO. Technical success was defined as successful cannulation of the common bile duct, with successful dilation and/or deployment of a biliary stent under fluoroscopy. Clinical success was defined as number of patients in the entire group who underwent ERCP successfully with resolution of symptoms. Results  We identified 64 patients (73 % men, 74 % white, median age 62 years) with a preexisting duodenal stent who underwent 85 attempts at ERCP. ERCP was technically successful in 50 of 85 procedures (59 %). Overall ERCP was successful in 41 of 85 patients (48 %). ERCP was more likely to be successful in patients with Type 1 and 3 duodenal strictures than with Type 2 strictures (83 % and 92 % vs. 42 %, P  < 0.01), in patients with a preexisting sphincterotomy (79% vs. 20 %, P  = 0.01) or preexisting biliary stent (66 % vs. 34 %, P  = 0.04). Adverse events included bleeding (n = 3), post-procedure fever (n = 3) and abdominal pain (n = 1). Conclusions  Although biliary stenting via ERCP is often technically challenging in patients with a prior duodenal stent, it is a safe and effective method of biliary drainage. ERCP should be attempted in patients with Type 1 and 3 duodenal strictures, a prior sphincterotomy or an indwelling biliary stent.

Efficacy of primary drainage by endoscopic ultrasound-guided biliary drainage for unresectable pancreatic adenocarcinoma

BACKGROUND AND AIM

Obstructive jaundice induced by pancreatic adenocarcinoma is typically treated with biliary drainage with endoscopic retrograde cholangiopancreatography (ERCP)-guided biliary drainage (ERCP-BD). Recently, endoscopic ultrasonography-guided biliary drainage (EUS-BD) was employed as an alternative method after ERCP-BD failed. We aimed to determine the efficacy and safety of EUS-BD for primary biliary drainage.

METHODS

Between December 2011 and February 2019, at Kawasaki General Medical Center, we retrospectively enrolled 33 patients who had undergone endoscopic biliary drainage with a metal stent, in a first attempt to relieve obstructive jaundice caused by unresectable pancreatic adenocarcinoma. We compared the technical and clinical outcomes between ERCP-BD and EUS-BD.

RESULTS

Twenty-three patients underwent ERCP-BD and 10 underwent EUS-BD. Both groups achieved 100% technical success. The clinical success rates were similar between the groups: 91% (21/23 patients) for ERCP-BD and 100% (10/10 patients) for EUS-BD (P = 0.48). Biliary obstruction recurred in 6/23 patients (26%) treated with ERCP-BD and 1/10 patients (10%) treated with EUS-BD (P = 0.40). Other adverse events occurred in 4/23 patients (17%) in the ERCP-BD group and 1/10 patients (10%) in the EUS-BD group (P = 0.99).

CONCLUSION

We suggest that EUS-BD could be employed for primary biliary drainage in patients with obstructive jaundice caused by unresectable pancreatic adenocarcinoma.

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.

Endoscopic Double Stenting for the Management of Combined Malignant Biliary and Duodenal Obstruction

Periampullary cancers are often diagnosed at advanced stages and can cause both biliary and duodenal obstruction. As these two obstructions reduce patients’ performance status and quality of life, appropriate management of the disease is important. Combined malignant biliary and duodenal obstruction is classified according to the location and timing of the duodenal obstruction, which also affect treatment options. Traditionally, surgical bypass (gastrojejunostomy and hepaticojejunostomy) has been performed for the treatment of unresectable periampullary cancer. However, it has recently been substituted by less invasive endoscopic procedures due to its high morbidity and mortality. Thus, endoscopic double stenting (transpapillary stenting and enteral stenting) has become the current standard of care. Limitations of transpapillary stenting include its technical difficulty and the risk of duodenal-biliary reflux. Recently, endoscopic ultrasound-guided procedures have emerged as a novel platform and have been increasingly utilized in the management of biliary and duodenal obstruction. As the prognosis of periampullary cancer has improved due to recent advances in chemotherapy, treatment strategies for biliary and duodenal obstruction are becoming more important. In this article, we review the treatment strategies for combined malignant biliary and duodenal obstruction based on the latest evidence.

Double stenting with EUS-CDS using a new anti-reflux metal stent for combined malignant biliary and duodenal obstruction

Highlight Sasaki and colleagues report their experience with double stenting combined with endoscopic ultrasound-guided choledochoduodenostomy using a new anti-reflux metal stent to prevent duodenobiliary reflux in combined biliary and duodenal obstruction. This double stenting method is a new strategy for the management of combined biliary and duodenal obstruction.

Double Stenting for Malignant Biliary and Duodenal Obstruction: A Systematic Review and Meta-Analysis

INTRODUCTION

Data about the efficacy of palliative double stenting for malignant duodenal and biliary obstruction are limited.

METHODS

A systematic literature search was performed to assess the feasibility and optimal method of double stenting for malignant duodenobiliary obstruction compared with surgical double bypass in terms of technical and clinical success, adverse events, reinterventions, and survival. Event rates with 95% confidence intervals were calculated.

RESULTS

Seventy-two retrospective and 8 prospective studies published until July 2018 were included. Technical and clinical success rates of double stenting were 97% (95%-99%) and 92% (89%-95%), respectively. Clinical success of endoscopic biliary stenting was higher than that of surgery (97% [94%-99%] vs 86% [78%-92%]). Double stenting was associated with less adverse events (13% [8%-19%] vs 28% [19%-38%]) but more frequent need for reintervention (21% [16%-27%] vs 10% [4%-19%]) than double bypass. No significant difference was found between technical and clinical success and reintervention rate of endoscopic retrograde cholangiopancreatography (ERCP), percutaneous transhepatic drainage, and endoscopic ultrasound-guided biliary drainage. ERCP was associated with the least adverse events (3% [1%-6%]), followed by percutaneous transhepatic drainage (10% [0%-37%]) and endoscopic ultrasound-guided biliary drainage (23% [15%-33%]).

DISCUSSION

Substantially high technical and clinical success can be achieved with double stenting. Based on the adverse event profile, ERCP can be recommended as the first choice for biliary stenting as part of double stenting, if feasible. Prospective comparative studies with well-defined outcomes and cohorts are needed.

Review of Simultaneous Double Stenting Using Endoscopic Ultrasound-Guided Biliary Drainage Techniques in Combined Gastric Outlet and Biliary Obstructions

Concomitant malignant gastric outlet obstruction and biliary obstruction may occur in patients with advanced cancers affecting these anatomical regions. This scenario presents a unique challenge to the endoscopist in selecting an optimal management approach. We sought to determine the efficacy and safety of endoscopic techniques for treating simultaneous gastric outlet and biliary obstruction (GOBO) with endoscopic ultrasound (EUS) guidance for biliary drainage. An extensive literature search for peer-reviewed published cases yielded 6 unique case series that either focused on or included the use of EUS-guided biliary drainage (EUS-BD) with simultaneous gastroduodenal stenting. In our composite analysis, a total of 51 patients underwent simultaneous biliary drainage through EUS, with an overall reported technical success rate of 100% for both duodenal stenting and biliary drainage. EUS-guided choledochoduodenostomy or EUS-guided hepaticogastrostomy was employed as the initial technique. In 34 cases in which clinical success was ascribed, 100% derived clinical benefit. The common adverse effects of double stenting included cholangitis, stent migration, bleeding, food impaction, and pancreatitis. We conclude that simultaneous double stenting with EUS-BD and gastroduodenal stenting for GOBO is associated with high success rates. It is a feasible and practical alternative to percutaneous biliary drainage or surgery for palliation in patients with associated advanced malignancies.

Efficacy and safety of chemotherapy after endoscopic double stenting for malignant duodenal and biliary obstructions in patients with advanced pancreatic cancer: a single-institution retrospective analysis

Background

Advanced pancreatic cancer is accompanied not only by bile duct obstruction, but also occasionally by duodenal obstruction. With new advances in chemotherapy and improvement in the management of stent dysfunction, the life expectancy of patients with pancreatic cancer has increased. This study aimed to evaluate the efficacy and safety of chemotherapy for advanced pancreatic cancer, as well as to analyze the prognostic factors, following endoscopic double stenting.

Methods

This retrospective study was conducted from January 1, 2007 to October 31, 2015 at an academic center. Fifty consecutive patients with pancreatic cancer who had undergone endoscopic double stenting, comprising duodenal and biliary stenting, were analyzed. We reviewed the patients records and analyzed the data of stent dysfunction rates after double stenting, reintervention for stent dysfunction, chemotherapy after double stenting, adverse events associated with chemotherapy after double stenting, survival times following double stenting, and overall survival times. The hospital’s institutional review board for human research approved this study.

Results

The overall survival time and the survival time following double stenting were 10.9 months (IQR 6.0–18.4 months) and 2.4 months (IQR 1.4–5.2 months), respectively. After double stenting, duodenal stent dysfunction occurred in 6 patients (12%), and biliary stent dysfunction occurred in 12 patients (24%), respectively. All patients who experienced stent dysfunction underwent endoscopic reintervention, and all of the procedures were successful. Twenty-one (42%) patients were treated with chemotherapy post double stenting; 9 patients received chemotherapy as a first-line treatment, 9 as a second-line treatment, and 3 as a third-line treatment. During chemotherapy, 8 (38%) patients had grade 3–4 adverse events, which were manageable. Chemotherapy post double stenting (OR, 0.19; 95% CI, 0.059–0.60; P = .0051), reintervention for biliary stent dysfunction (OR, 0.21; 95% CI, 0.081–0.50; P = .0002), and performance status (< 2) (OR, 0.28; 95% CI, 0.098–0.71; P = .0064) were significant prognostic factors after double stenting.

Conclusions

Systemic chemotherapy was manageable, even in patients with double stenting. Chemotherapy after double stenting and appropriate reintervention for stent obstructions potentially prolonged the survival of patients with advance pancreatic cancer.

Outcomes of endoscopic biliary drainage in pancreatic cancer patients with an indwelling gastroduodenal stent: a multicenter cohort study in West Japan

BACKGROUND AND AIMS

Gastroduodenal and biliary obstruction may occur synchronously or asynchronously in advanced pancreatic cancer, and endoscopic double stent placement may be required. EUS-guided biliary drainage (EUS-BD) often is performed after unsuccessful placement of an endoscopic transpapillary stent (ETS), and EUS-BD may be beneficial in double stent placement. This retrospective multicenter cohort study compared the outcomes of ETS placement and EUS-BD in patients with an indwelling gastroduodenal stent (GDS).

METHODS

We recorded the clinical outcomes of patients at 5 tertiary-care medical centers who required biliary drainage after GDS placement between March 2009 and March 2014.

RESULTS

Thirty-nine patients were included in this study. Patients' mean age was 68.5 years; 23 (59.0%) were men. The GDS overlay the papilla in 23 patients (59.0%). The overall technical success rate was significantly higher with EUS-BD (95.2%) than with ETS placement (56.0%; P < .01). Furthermore, the technical success rate was significantly higher with EUS-BD (93.3%) than with ETS placement (22.2%; P < .01) when the GDS overlies the papilla. The overall clinical success rate of EUS-BD also was significantly higher than for ETS placement (90.5% vs 52.0%, respectively; P = .01), and there was no significant difference in the incidence of adverse events (ETS, 32.0% vs EUS-BD, 42.9%; P = .65).

CONCLUSION

Endoscopic double stent placement with EUS-BD is technically and clinically superior to ETS placement in patients with an indwelling GDS. EUS-BD should be considered the first-line treatment option for patients with an indwelling GDS that overlies the papilla. ETS placement remains a reasonable alternative when the papilla is not covered by the GDS.

Covered duodenal self-expandable metal stents prolong biliary stent patency in double stenting: The largest series of bilioduodenal obstruction

BACKGROUND AND AIM

Endoscopic biliary and duodenal stenting (DS; double stenting) is widely accepted as a palliation therapy for malignant bilioduodenal obstruction. The aim of the current study was to investigate the patency and adverse events of duodenal and biliary stents in patients with DS.

METHODS

Patients who underwent DS from April 2004 to March 2017 were analyzed retrospectively with regard to clinical outcomes and predictive factors of recurrent biliary and duodenal obstruction (recurrent biliary obstruction [RBO] and recurrent duodenal obstruction [RDO]).

RESULTS

A total of 109 consecutive patients was enrolled. Technical success of DS was achieved in 108 patients (99.1%). Symptoms due to biliary and duodenal obstruction were improved in 89 patients (81.7%). RBO occurred in 25 patients (22.9%) and RDO in 13 (11.9%). The median times to RBO and RDO from DS were 87 and 76 days, respectively. Placement of a duodenal uncovered self-expandable metal stent (U-SEMS) was significantly associated with RBO in the multivariable analysis (P = 0.007). Time to RBO was significantly longer in the duodenal covered self-expandable metal stent group than in the U-SEMS group (P = 0.003). No predictive factors of RDO were detected, and duodenal stent type was not associated with the time to RDO (P = 0.724).

CONCLUSIONS

Double stenting was safe and effective for malignant bilioduodenal obstruction. Duodenal U-SEMS is a risk factor for RBO. The covered self-expandable metal stent is the preferred type of duodenal SEMS in patients with DS (Clinical trial registration number: UMIN000027606).