Clinical efficacy of anti-migration features in fully covered metallic stents for anastomotic biliary strictures after liver transplantation: comparison of conventional and anti-migration stents

Management of biliary complications in liver transplant recipients using a fully covered self-expandable metal stent with antimigration features

BACKGROUND

Following liver transplant (LT) with duct-to-duct anastomosis, biliary strictures and leaks are typically managed with endoscopic retrograde cholangiopancreatography (ERCP) and stenting. While multiple side-by-side plastic stents are typically used for management of anastomotic strictures, fully covered self-expandable metal stents (FCSEMS) can be used to decrease the number of ERCPs with longer periods of stent patency. The risk of migration can limit their use. FCSEMS with antimigration fins to manage benign biliary complications following LT may provide stricture resolution with limited adverse events (AEs).

METHODS

Single center retrospective study of LT patients who required FCSEMS from 1/2014 to 4/2022. Primary outcomes included stricture resolution and recurrence. Secondary outcomes were stent migration, occlusion, removability, and number of ERCPs.

RESULTS

Forty-three patients (mean age 55.5 years) with anastomotic strictures (N.=37), bile leaks (N.=4) or both (N.=2) were included. The median time from LT to FCSEMS placement was 125 days. Within one year of LT, 31 patients required intervention; early intervention at less than 30 and 90 days was needed in 7 and 19 patients, respectively. The median length of follow-up was 816.5 days. Stricture resolution was seen in 35 patients (81%) after a median stent dwell time of 130.5 days; recurrence occurred in 8 patients. There were three instances of partial stent migration that did not require reintervention or interfere with removability. The mean number of ERCPs required was 2.5.

CONCLUSIONS

The use of a FCSEMS with antimigration features yields effective stricture resolution with longer stent dwell times and fewer ERCPs.

Long-term outcomes of fully covered self-expandable metal stents for refractory biliary strictures after living donor liver transplantation: a retrospective study at a tertiary center

BACKGROUND AND AIMS

Endoscopic multiple plastic stents are an established first-line treatment for anastomotic biliary stricture (ABS) management after liver transplantation (LT). Fully covered self-expandable metallic stents (FCSEMSs) have recently been used with favorable outcomes, but long-term treatment outcomes remain an issue for ABS. We evaluated the long-term outcomes of FCSEMS for the management of refractory ABS after LT.

METHODS

We reviewed the prospectively collected and maintained endoscopic retrograde cholangiography database at Asan Medical Center to retrieve consecutive post-LT ABS cases that underwent an endoscopic FCSEMS placement between August 2009 and August 2019 after MPS placement failure.

RESULTS

A total of 34 patients were enrolled in this study. Technical success had been achieved in all subjects (100%). The median stent placement duration was 3.1 months (IQR 2.7-6.1). Stricture resolution was achieved in 26 patients (clinical success 76.5%, 95% confidence interval 62-91). Early adverse events developed in 3 patients (8.8%), including distal stent migration. Late adverse events occurred in 9 patients (26.5%), including cholangitis (n = 7, 20.6%) and asymptomatic distal stent migration (n = 2, 5.9%). The median follow-up period was 57.9 months (IQR 51.9-64.3). Stricture recurrence occurred in 3 of 26 patients who achieved clinical success (11.5%).

CONCLUSIONS

FCSEMS placement appears to be an effective and advisable intervention for refractory ABS as it can provide persistent stricture improvement over the long-term.

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

BACKGROUND AND AIMS

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Antimigration versus conventional fully covered metal stents in the endoscopic treatment of anastomotic biliary strictures after deceased-donor liver transplantation

INTRODUCTION

Migration of fully covered metal stents (FCMS) remains a limitation of the endoscopic treatment of anastomotic biliary strictures (ABS) following orthotopic liver transplantation (OLT). The use of antimigration FCMS (A-FCMS) might enhance endoscopic treatment outcomes for ABS.

METHODS

Single center retrospective study. Consecutive patients with ABS following OLT who underwent ERCP with FCMS placement between January 2005 and December 2020 were eligible. Subjects were grouped into conventional-FCMS (C-FCMS) and A-FCMS. The primary outcome was stent migration rates. Secondary outcomes were stricture resolution, adverse event, and recurrence rates.

RESULTS

A total of 102 (40 C-FCMS; 62 A-FCMS) patients were included. Stent migration was identified at the first revision in 24 C-FCMS patients (63.2%) and in 21 A-FCMS patients (36.2%) (p = 0.01). The overall migration rate, including the first and subsequent endoscopic revisions, was 65.8% in C-FCMS and 37.3% in A-FCMS (p = 0.006). The stricture resolution rate at the first endoscopic revision was similar in both groups (60.0 vs 61.3%, p = 0.87). Final stricture resolution was achieved in 95 patients (93.1%), with no difference across groups (92.5 vs 93.5%; p = 0.84). Adverse events were identified in 13 patients (12.1%) with no difference across groups. At a median follow-up of 52 (IQR: 19-85.5) months after stricture resolution, 25 patients (24.5%) developed recurrences, with no difference across groups (C-FCMS 30% vs A-FCMS 21%; p = 0.28).

CONCLUSIONS

The use of A-FCMS during ERCP for ABS following OLT results in significantly lower stent migration rates compared to C-FCMS. However, the clinical benefit of reduced stent migration is unclear. Larger studies focusing on stricture resolution and recurrence rates are needed.

Structural optimization and in vivo evaluation of a colorectal stent with anti-migration and anti-tumor properties

Clinically, colorectal stents can only palliatively relieve obstruction caused by colorectal cancer (CRC), with a high incidence of stent migration and tumor-related re-obstruction. To overcome these shortcomings, we developed a colorectal stent composed of a structure-optimized nitinol braided stent and a tubular film including an inner layer of poly (ethylene-co-vinyl acetate) (EVA) and a segmental outer layer of EVA with paclitaxel (PTX). The braiding pattern, segment number, and end shape of the stent were optimized based on the mechanical properties, ex vivo and in vivo anti-migration performance, and tissue response of the stent. The optimized nitinol stent had a structure of one middle segment in a hook-pattern and two end segments in a cross-pattern with two studs on each end in a staggered arrangement. Structure-optimized colorectal stents were prepared and evaluated in vivo. PTX released from the stent was mostly distributed in the rabbit rectum in contact with it. The biosafety of the colorectal stent was evaluated using blood tests, biochemical analysis, anatomical observation, and pathological analysis. The anti-tumor effect of the stent was also evaluated by endoscopy, anatomical observation, and pathological and immunohistochemical analyses in rabbits with orthotopic CRC. The results demonstrate that the optimized colorectal stents have effective anti-migration ability and anti-tumor effects with good biosafety. STATEMENT OF SIGNIFICANCE: In order to overcome the most common disadvantages of migration and re-obstruction of colorectal stents clinically, a colorectal stent composed of a structure-optimized nitinol stent and a tubular film including an inner layer of EVA and a segmental outer layer of EVA with PTX was put forward in this study. The optimized nitinol stent had a structure of one middle segment in hook-pattern and two end segments in cross-pattern with two studs on each end in staggered arrangement. The resulting colorectal stent has been proved with good anti-migration ability, anti-tumor effects, and biosafety in vivo, which provides a safe and effective potential treatment modality for patients with colorectal cancer.

Endoscopic therapy using a self-expandable metallic stent with an anti-migration system for postorthotopic liver transplantation anastomotic biliary stricture

BACKGROUND

Endoscopic therapy using multiple plastic stents (MPSs) is the standard therapy for postorthotopic liver transplantation (p-OLT) anastomotic biliary stricture (ABS). However, this approach demands repeated procedures. Recent studies using fully covered self-expandable metallic stents (FCSEMS) have shown encouraging results, but migration occurs in 10% to 40% of cases. The objective of this retrospective study was to evaluate the efficacy of endoscopic treatment using FCSEMS with an anti-migration system (Am-FCSEMS) in patients with p-OLT ABS.

AIM

To evaluate the efficacy of endoscopic treatment using an Am-FCSEMS in patients with p-OLT ABS.

METHODS

This study was conducted in a private tertiary care centre in São Paulo, Brazil and was approved by our institution's Human Research Committee. From April 2018 to October 2020, regardless of previous endoscopic treatment (MPS or FCSEMS), 17 patients with p-OLT ABS and indications for endoscopic therapy were included in this study. The exclusion criteria were pregnancy, nonanastomotic biliary or hilar stricture, hepatic artery stenosis/thrombosis, isolated biliary fistulae, a distance shorter than 2 cm from the stricture to the hepatic hilum, and patient refusal. The primary endpoint was the efficacy of p-OLT ABS endoscopic treatment using an Am-FCSEMS that remained in place for a 12-mo period. Biliary sphincterotomy was performed in patients with native papilla, and an Am-FCSEMS (10 mm in final diameter and 60 or 80 mm in length) was placed (Hanarostent^TM MI Tech, Co). Balloon stricture dilation was performed only if necessary to introduce the stent.

RESULTS

Three patients were excluded due to loss to follow-up before stent removal. Among the 14 patients included and followed, 7 were women, and the average age was 56 years (range: 28-76). The average period of Am-FCSEMS placement was 362 ± 109 d. Technical success occurred in all 14 patients (100%). There were no cases of distal stent migration. Complete resolution of the stricture occurred in 13/14 patients (92.85%). Adverse events occurred in 3/14 patients (21.42%): 2 patients with mild acute pancreatitis (14.28%) and 1 patient (7.14%) with stent dysfunction (occlusion by biliary sludge and stones, which was treated endoscopically without the need for stent removal). No deaths occurred related to therapy. All stents were removed using foreign body forceps or snares without difficulty. After Am-FCSEMS removal, all 13 patients who had ABS resolution were followed-up for an average of 411 ± 172 d, and there was no stricture recurrence or need for further endoscopic therapy.

CONCLUSION

In this retrospective study, endoscopy therapy using an Am-FCSEMS for p-OLT ABS was safe and effective, with a high stricture resolution rate that was probably due to the absence of stent migration.

Migration rate using fully covered metal stent in anastomotic strictures after liver transplantation: Results from the BASALT study group

BACKGROUND AND STUDY AIM

The traditional endoscopic therapy of anastomotic strictures (AS) after orthotopic liver transplantation (OLT) is multiple ERCPs with the insertion of an increasing number of plastic stents side-by-side. Fully covered self-expanding metal stents (cSEMS) could be a valuable option to decrease the number of procedures needed or non-responders to plastic stents. This study aims to retrospectively analyse the results of AS endoscopic treatment by cSEMS and to identify any factors associated with its success.

PATIENTS AND METHODS

Ninety-one patients (mean age 55.9 ± 7.6 SD; 73 males) from nine Italian transplantation centres, had a cSEMS positioned for post-OLT-AS between 2007 and 2017. Forty-nine (54%) patients were treated with cSEMS as a second-line treatment.

RESULTS

All the procedures were successfully performed without immediate complications. After ERCP, adverse events occurred in 11% of cases (2 moderate pancreatitis and 8 cholangitis). In 49 patients (54%), cSEMSs migrated. After cSEMS removal, 46 patients (51%) needed further endoscopic (45 patients) or radiological (1 patient) treatments to solve the AS. Lastly, seven patients underwent surgery. Multivariable stepwise logistic regression showed that cSEMS migration was the only factor associated with further treatments (OR 2.6, 95% CI 1.0-6.6; p value 0.03); cSEMS implantation before 12 months from OLT was associated with stent migration (OR 5.2, 95% CI 1.7-16.0; p value 0.004).

CONCLUSIONS

cSEMS appears to be a safe tool to treat AS. cSEMS migration is the main limitation to its routinary implantation and needs to be prevented, probably with the use of new generation anti-migration stents.

Post-Transplant Biliary Strictures: An Updated Review

Liver transplantation (LT) is the only curative therapy in patients with end-stage liver disease with excellent long-term survival; however, LT recipients are at risk of significant complications. Among these complications are biliary complications with an incidence ranging from 5 to 32% and associated with significant post-LT morbidity and mortality. Prompt recognition and management are critical as these complications have been associated with mortality rates up to 19% and retransplantation rates up to 13%. An important limitation of published studies is that a large proportion does not discriminate between anastomotic strictures and nonanastomotic strictures. This review aims to summarize our current understanding of risk factors and natural history, diagnostic testing, and treatment options for post-LT biliary strictures.

Studying in vivo and in vitro effects of a novel polyvinyl benzyl chloride-D-glucaro-1, 4-lactonate polymer-coated bile duct stent for anti-biliary mud deposition

Background:

We aim to coat a novel polyvinyl benzyl chloride-D-glucaro-1, 4-lactonate polymer-coated bile duct stent for anti-biliary mud deposition and investigate its in vivo and in vitro impacts. Biliary mud deposition is a leading cause of plastic biliary stent obstruction after its placement. Orally administrated D-glucaro-1, 4-lactonate is a specific competitive inhibitor of β-glucuronidase that causes biliary mud deposition.

Methods:

In this study, the stents coated with polyvinyl benzyl chloride-D-glucaro-1,4-lactonate polymer (PVBC-DGL) were placed in an ex vivo bile duct model perfused with porcine bile and observed every week until completely blocked. Post establishing the model of bile duct stenosis in piglets, stents are observed through endoscopy, hematology, patency time, and pathological changes within 6 months.

Results:

The 70% PVBC-DGL stents achieved the highest percentage of the inhibitory effect when the drugs were completely released in vitro. Results were obtained from 14 pigs (5: no coating (original), 4: 0% coating, and 5: 70% coating). The overall patency time of the stents was prolonged in all groups; however, the group with 70% coated stents showed a significantly prolonged patency time as compared to no coating (original) and the 0% coating groups in pigs (23.4 ± 1.8 vs 11.2 ± 2.1 w ( p = 0.05); 23.4 ± 1.8 vs 10.5 ± 2.5 w ( p = 0.05), respectively).

Conclusion:

The stents with 70% PVBC-DGL better prevent and control the deposition of bile mud and prolong the patency time of stent placement in the subject animals and may be proposed for further clinical trials in patients.

Fishing line assisted endoscopic placement of multiple plastic biliary stents for unresectable malignant hilar biliary obstruction: a retrospective study

BACKGROUND AND AIMS

Stent migration is one of the most common complications during the placement of multiple plastic biliary stents (MPBS) under endoscopy. This study aims to evaluate the feasibility and efficiency of the fishing line assisted (FLA) method for preventing the complication.

METHODS

Patients with unresectable malignant hilar biliary obstruction (MHBO) who undergone endoscopic placement of MPBS using the FLA or conventional method from May 2018 to April 2021 in our center were enrolled in the study. The endpoints of this study were the stent migration rate, technical success rates, adverse events rates, times of stent migration, and the procedure time.

RESULTS

FLA group (N = 19) and conventional group (N = 22) had similar baseline characteristics of the patients. The technical success rates (100% vs. 95.5%; P > 0.05), ERCP-related adverse events rates (5.3% vs. 4.5%; P > 0.05), and the stent-related adverse events rates (0% vs. 4.5%; P > 0.05) were no significant differences between the FLA and conventional groups. MPBS inserted using the conventional method consumed more time (median, 33.9 min vs. 15.6 min; P < 0.05) method and increased the times of stent migration (median, 3 times vs. 0 times; P < 0.05) than using the FLA method. Even if no statistical difference was detected in the stent migration rate between groups, this rate was lower in the FLA group than the conventional group (0% vs. 13.6%; P > 0.05).

CONCLUSIONS

FLA method is an effective technique for MPBS implantation to prevent stent migration during endoscopic retrograde cholangiography (ERCP). The method should be applied to patients with unresectable MHBO who need to place MPBS.

Novel Uses of Lumen-apposing Metal Stents: A Review of the Literature

The field of therapeutic endoscopy has seen many recent advancements. One such emerging field is the use of lumen-apposing metal stents (LAMS). Although a few LAMS have been developed, the most commonly reviewed and the only Food and Drug Administration (FDA)-approved LAMS is the Axios stent by Boston Scientific. In 2013, LAMS were initially approved by the FDA for the management of pancreatic fluid collection drainage in the presence walled-off necrosis. Pancreatic fluid collections are traditionally drained with either a plastic stent or a covered biliary self-expanding metal stent. Plastic stents have a double pigtail feature which prevents stent migration. However, their narrow lumen poses limitations as it can lead to early stent occlusion. Fully covered metal stents have larger diameters, allowing improved drainage and decreased stent occlusion but their tubular shape is prone to migration. Consequently, this results in leakage, and frequent retrievals. Over the years, due to their versatility, LAMS now have many off label uses. This includes management of gastric outlet obstruction, superior mesenteric artery syndrome, strictures, gallbladder drainage, and postsurgical collection drainage. In this review, we will be discussing the FDA approved and the nonapproved uses of LAMS.

Diagnosis and management of benign biliary strictures post liver transplantation in adults

Benign biliary strictures after liver transplantation are common and can lead to graft dysfunction and decreased patient survival. Post-transplant strictures are classified as anastomotic or non-anastomotic which differ in response to therapy. Risk factors for biliary strictures following transplantation include impaired blood supply, surgical factors, and biliary anomalies. Patients can present with biliary obstruction but most will be asymptomatic, with only abnormal graft function. MRCP is the most sensitive noninvasive tool for diagnosing biliary complications. In most centres worldwide endoscopy is used first-line in the management of anastomotic strictures, although there is significant variation in endoscopic technique employed; including dilation, placing a single or multiple plastic stents, a fully covered metal stent and most recently using intra-ductal fully covered metal stents. With the introduction of fully covered metal stents the number of interventions patients require has reduced and overall the clinical success of the endoscopic approach has steadily improved. Percutaneous and surgical treatments are now reserved for patients in whom endoscopic management fails or who have had Roux-en-Y anastomoses. However even in these cases, combined procedures with interventional radiology, or implementation of enteroscopy and EUS-guided approaches now means very few patients ultimately require surgical revision.

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).

Anastomotic bilio-biliary stricture after adult liver transplantation: A retrospective study over 20 years in a single center

BACKGROUND

Biliary complications are the main surgical complication after liver transplantation (LT). The aims of the present retrospective single center study were to describe anastomotic bilio-biliary strictures (ABS) in a large cohort of liver transplant recipients with long follow-up.

METHODS

All adult LT recipients who underwent a LT, with bilio-biliary anastomosis, between 1990 and 2010 in Edouard Herriot hospital, Lyon, France were included in the study.

RESULTS

The study population consisted in 783 patients (70.0% males), median age 50.5 years; main indication was alcohol-related liver disease (46.8%). The median follow-up after LT was 11.9 years (range 0-27 years). The overall incidence of anastomotic biliary complications was 9.7%: 50 patients developed an ABS (6.6%), after a median delay of 4.4 months (range 0.1-245.2) after LT and 32 (4.1%) developed biliary leakage after a median delay of 25 days (range 1-179). The actuarial risk of developing an ABS was 1.6% at 1-month, 2.7% at 3-months, 4.1% at 6-months, and 5.1%, 6.0%, 6.4%, 6.6%, 7.3% at 1-, 2-, 5-, 10- and 15-years, respectively. Univariate analysis disclosed that post-reperfusion syndrome and liver graft steatosis (≥30%) were significant risk factors for ABS. Multivariate analysis disclosed that graft steatosis (OR=6.262, 95%CI 1.936-20.257, P=0.002) and MELD score (OR=1.071, 95%CI 1.018-1.128, P=0.008) were significant risk factors for ABS. The first-line treatment of ABS consisted in endoscopic stenting for 44 patients (88.0%) and immediate success rate was 75.0%. Delayed recurrence of ABS occurred in 8/33 patients (24.0%).

CONCLUSION

Our results suggest that steatotic grafts should be used for recipients without severe liver failure to avoid ABS, and that endoscopic stenting of post-LT ABS leads to a high success rate, but is associated with a significant risk of recurrence.

Benign Biliary Strictures: A Systematic Review on Endoscopic Treatment Options

Benign biliary strictures can be difficult to manage. Untreated biliary strictures can lead to complications, such as chronic cholestasis, jaundice, recurrent sepsis, and secondary biliary cirrhosis, which can have severe ramifications. The management landscape is constantly evolving, with the development of modifiable self-expandable metal stents and biodegradable stents. This review critically appraises current endoscopic treatment strategies, in particular focusing on the shortfalls, such as stent migration and stricture recurrence. It also proposes a treatment algorithm based on aetiologias and the location of the strictures.

Recent innovations in therapeutic endoscopy for pancreatobiliary diseases

The development of endoscopic treatment for pancreatobiliary diseases in recent years is remarkable. In addition to conventional transpapillary treatments under endoscopic retrograde cholangiopancreatography (ERCP), new endoscopic ultrasound-guided therapy is being developed and implemented. On the other hand, due to the development/improvement of various devices such as new metal stents, a new therapeutic strategy under ERCP is also advocated. The present review focuses on recent advances in the endoscopic treatment of pancreatic pseudocysts, walled-off necrosis, malignant biliary strictures, and benign biliary/pancreatic duct strictures.

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).

The Status of SEMS Versus Plastic Stents for Benign Biliary Strictures

PURPOSE OF REVIEW

Benign biliary strictures can be treated with plastic stents and self-expandable metal stents (SEMS). This review article delineates the latest scientific evidence for their usage.

RECENT FINDINGS

Despite evolving literature on both type of stents as treatment modalities of benign biliary strictures, which encompass mainly anastomotic strictures and strictures related to chronic pancreatitis, no final conclusions can be drawn regarding the superiority of a particular stent. SEMS tend to have higher stricture resolution rates and fewer procedural requirements which are partly offset by higher stent migration and stricture recurrence rates compared with plastic stents. Additional studies focusing on new SEMS types with anti-migration features as well as cost-effectiveness calculations are necessary for clinical decision-making when treating patients with benign biliary strictures.