Management of complications associated with partially covered biliary metal stents

Therapeutic biliary stents: applications and opportunities

INTRODUCTION

Biliary stents are used to optimize ductal patency and enable bile flow in the management of obstruction or injury related to biliary tract tumors, strictures, stones, or leaks. Although direct therapeutic applications of biliary stents are less well developed, stents can be used to deliver drugs, radioisotopes, and photodynamic therapy.

AREAS COVERED

This report provides an in-depth overview of the clinical indications, and therapeutic utility of biliary stents. Unique considerations for the design of biliary stents are described. The properties and functionalities of materials used for stents such as metal alloys, plastic polymers, or biodegradable materials are described, and opportunities for design of future stents are outlined. Current and potential applications of stents for therapeutic applications for biliary tract diseases are described.

EXPERT OPINION

Therapeutic biliary stents could be used to minimize inflammation, prevent stricture formation, reduce infections, or provide localized anti-cancer therapy for biliary tract cancers. Stents could be transformed into therapeutic platforms using advanced materials, 3D printing, nanotechnology, and artificial intelligence. Whilst clinical study and validation will be required for adoption, future advances in stent design and materials are expected to expand the use of therapeutic biliary stents for the treatment of biliary tract disorders.

Side-by-side placement of fully covered metal stents versus conventional 7F plastic stents in malignant hilar biliary obstruction: Prospective randomized controlled trial

OBJECTIVES

We aimed to evaluate the efficacy and safety of metal stents compared with plastic stents when bilateral side-by-side stents were deployed for malignant hilar biliary obstruction (MHBO).

METHODS

Fifty patients with unresectable advanced MHBO were randomly assigned to the metal stent (MS, n = 25) or plastic stent group (PS, n = 25). Fully covered self-expandable metal stents with 6 mm diameter and plastic stents with either 7F straight or double pigtail were used for MS and PS groups, respectively. Time to recurrent biliary obstruction (TRBO) was evaluated as the primary outcome.

RESULTS

Both groups had 100% technical success rates; 88% and 76% of clinical success rates were obtained in MS and PS, respectively. Although stent migrations were more frequent in MS than PS (48% vs. 16%, P = 0.02), the mean TRBO was significantly longer in MS (190 days; 95% confidence interval [CI] 121-260 days vs. 96 days; 95% CI 50-141 days, P = 0.02). The placement of plastic stents (hazard ratio 2.42; 95% CI 1.24-4.73; P = 0.01) was the only significant risk factor associated with TRBO in multivariable analysis. The rates of adverse events were similar between the two groups (difference 0%; 95% CI -25% to 25%; P > 0.99).

CONCLUSIONS

During bilateral side-by-side deployment in MHBO, the use of metal stents appears to be preferable to plastic stents in terms of TRBO, despite a higher frequency of stent migration.

Two salvage techniques using a large dilation balloon: Endoscopic recovery of a migrated biliary metal stent and endoscope passage through a difficult duodenal stricture in combination with a duodenal stent

There have been several reports of endoscopic removal of biliary metal stents using forceps or stent-in-stent techniques. Nishikawa and colleagues describe the endoscopic recovery of a proximally migrated biliary metal stent using a large dilation balloon and endoscope passage through a difficult duodenal stricture in combination with a duodenal stent.

Endoscopic retrieval of a proximally migrated fully covered self-expandable metal stent using biopsy forceps with a guiding sheath cannula

Transpapillary endoscopic biliary drainage is the gold standard for resolving malignant biliary obstruction. Stent migration occasionally occurs and is troublesome to retrieve. Yamamoto and colleagues report with accompanying video on the successful retrieval of a proximally migrated stent using biopsy forceps through a guiding sheath cannula.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Comparative Efficacy of Various Stents for Palliation in Patients with Malignant Extrahepatic Biliary Obstruction: A Systematic Review and Network Meta-Analysis

Although many studies have investigated the efficacy of stent placement for patients with malignant extrahepatic biliary obstruction, the clinical outcomes and adverse events of biliary stenting have not been comprehensively evaluated. We searched all relevant randomized-controlled trials that evaluated the comparative efficacy of biliary stents, including the plastic stents, uncovered self-expandable metal stents (SEMSs), and covered SEMSs in patients with malignant extrahepatic biliary obstructions. Twenty-one studies with 2326 patients were included. Both uncovered and covered SEMSs had a lower risk of recurrent biliary obstruction (RBO) compared to plastic stents (risk ratio (RR) (95% confidence interval [CI]): uncovered vs. plastic, 0.46 (0.35–0.62); covered vs. plastic, 0.46 (0.34–0.62)). A comparison of the groups using SEMSs revealed that tumor ingrowth was common in the uncovered SEMS group, while stent migration, tumor overgrowth, and occlusion by sludge were common in the covered SEMS group; however, the overall risk of RBO did not differ between these groups (RR (95% CI): uncovered vs. covered: 1.02 (0.80–1.30)). Although the main causes of RBO vary across stents, RBO risk was similar between uncovered and covered SEMS groups. Both SEMSs have superior efficacy in terms of RBO compared to plastic stents.

Endoscopic Management of a Proximally Migrated Fully Covered SEMS Using the Stent-in-Stent Technique

Endoscopic biliary decompression via stent placement is an important approach for the palliative management of distal malignant biliary obstruction. However, migration of the inserted stent can occur, either distally or proximally; proximal migration is less common, but it also presents a greater challenge for endoscopic resolution. We present a case of a 67-year-old woman who had locally advanced pancreatic cancer and developed a common bile duct obstruction. Upon clinical presentation of chronic, painless, progressive jaundice, the obstruction was managed by placing of a 10 mm × 60 mm covered self-expandable metal stent (CSEMS), which successfully facilitated palliative biliary drainage. Six months later, however, the patient developed recurrent jaundice, which was determined to be due to proximal migration of the CSEMS. Repeat endoscopic retrograde cholangiography was performed, and initial attempts to retrieve the migrated stent failed. Finally, another 10 mm × 60 mm CSEMS was placed across the stricture site, inside the previous stent, which remained in place. The treatment resolved the obstruction and jaundice, and the patient experienced no adverse events.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Treatment of benign biliary leaks with transhepatic placement of coated self-expanding metallic stents

OBJECTIVES

To analyze the safety and efficacy of percutaneous placement of coated self-expanding metallic stents (SEMS) in patients with biliary leaks.

MATERIAL AND METHODS

This ethics committee at our center approved this study. We retrospectively reviewed all coated SEMS placed between October 2008 and September 2015. We analyzed patient-related factors such as the primary underlying disease, prior hepatic procedures, and clinical outcome. We evaluated the location, the number and type of leak (anastomotic or non-anastomotic), and the characteristics of the interventional procedure (number of stents deployed, location of the stents, technical success, and primary functionality). We recorded the complications registered.

RESULTS

We studied 14 patients (11 men and 3 women). The mean follow-up period was 375.5 days (range 15-1920 days). Leaks were postsurgical in 12 patients. One patient developed an arteriobilioportal fistula. In another, the biliary leak occurred secondary to the rupture of the common bile duct after ERCP. A total of 23 coated SEMS were placed, including 21 Fluency^® stents (Bard, Tempe, AZ, USA) and 2 Wallflex^® stents (Boston Scientific, Galway, Republic of Ireland). The technical success of the procedure was considered total in 11 (78.6%) patients, partial in 2 (14.3%) patients, and null in 1 (7.2%) patient. The clinical outcome was good in 13 of the 14 patients. The mean period of primary functionality of the coated SEMS was 331 days (range 15-1920 days). No major complications were observed in 11 (78.6%) patients.

CONCLUSIONS

Percutaneous placement of coated SEMS for the treatment of benign biliary leaks is safe and efficacious, with a high rate of technical and clinical success and a moderate rate of complications.

Covered versus uncovered self-expandable metal stents for malignant biliary strictures: A meta-analysis and systematic review

Self-expandable metal stents (SEMS) are used for palliating inoperable malignant biliary strictures. It is unclear if covered metal stents are superior to uncovered metal stents in these patients. We compared clinical outcomes in patients with covered and uncovered stents. Studies using covered and uncovered metallic stents for palliation in patients with malignant biliary stricture were reviewed. Articles were searched in MEDLINE, PubMed, and Ovid journals. Fixed and random effects models were used to calculate the pooled proportions. Initial search identified 1436 reference articles, of which 132 were selected and reviewed. Thirteen studies (n = 2239) for covered and uncovered metallic stents which met the inclusion criteria were included in this analysis. Odds ratio for stent occlusion rates in covered vs. uncovered stents was 0.79 (95 % CI = 0.65 to 0.96). Survival benefit in patients with covered vs. uncovered stents showed the odds ratio to be 1.29 (95 % CI = 0.95 to 1.74). Pooled odds ratio for migration of covered vs. uncovered stents was 9.9 (95 % CI = 4.5 to 22.3). Covered stents seemed to have significantly lesser occlusion rates, increased odds of migration, and increased odds of pancreatitis compared to uncovered stents. There was no statistically significant difference in the survival benefit, overall adverse event rate, and patency period of covered vs. uncovered metal stents in patients with malignant biliary strictures.

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

OBJECTIVE

Covered self-expandable metal stents (SEMSs) are increasingly used as alternatives to uncovered SEMSs for the palliation of inoperable malignant distal biliary obstruction to counteract tumor ingrowth. We aimed to compare the outcomes of partially covered and uncovered SEMSs with identical mesh structures and anti-migration properties, such as low axial force and flared ends.

MATERIALS AND METHODS

One hundred and three patients who were diagnosed with inoperable malignant distal biliary obstruction between January 2006 and August 2013 were randomly assigned to either the partially covered (n = 51) or uncovered (n = 52) SEMS group.

RESULTS

There were no significant differences in the cumulative stent patency, overall patient survival, stent dysfunction-free survival and overall adverse events, including pancreatitis and cholecystitis, between the two groups. Compared to the uncovered group, stent migration (5.9% vs. 0%, p = 0.118) and tumor overgrowth (7.8% vs. 1.9%, p = 0.205) were non-significantly more frequent in the partially covered group, whereas tumor ingrowth showed a significantly higher incidence in the uncovered group (5.9% vs. 19.2%, p = 0.041). Stent migration in the partially covered group occurred only in patients with short stenosis of the utmost distal bile duct (two in ampullary cancer, one in bile duct cancer), and did not occur in any patients with pancreatic cancer.

CONCLUSIONS

For the palliation of malignant distal biliary obstruction, endoscopic placement of partially covered SEMSs with anti-migration designs and identical mesh structures to uncovered SEMSs failed to prolong cumulative stent patency or reduce stent migration.

Current Status of Biliary Metal Stents

Many advances have been achieved in biliary stenting over the past 30 years. Endoscopic stent placement has become the primary management therapy to relieve obstruction in patients with benign or malignant biliary tract diseases. Compared with plastic stents, a self-expandable metallic stent (SEMS) has been used for management in patients with malignant strictures because of a larger lumen and longer stent patency. Recently, SEMS has been used for various benign biliary strictures and leaks. In this article, we briefly review the characteristics of SEMS as well as complications of stent placement. We review the current guidelines for managing malignant and benign biliary obstructions. Recent developments in biliary stenting are also discussed.

Management of liver transplantation biliary stricture: Results from a tertiary hospital

AIM: To review results of endoscopic treatment for anastomotic biliary strictures after orthotopic liver transplantation (OLT) during an 8-year period.

METHODS: This is a retrospective review of all endoscopic retrograde cholangiopancreatographys (ERCPs) performed between May 2006 and June 2014 in deceased OLT recipients with anastomotic stricture at a tertiary care hospital. Patients were divided into 2 groups, according to the type of stent used (multiple plastic or covered self-expandable metal stents), which was chose on a case-by-case basis and their characteristics. The primary outcome was anastomotic stricture resolution rate determined if there was no more than a minimum waist at cholangiography and a 10 mm balloon could easily pass through the anastomosis with no need for further intervention after final stent removal. Secondary outcomes were technical success rate, number or ERCPs required per patient, number of stents placed, stent indwelling, stricture recurrence rate and therapy for recurrent anastomotic biliary stricture (AS). Stricture recurrence was defined as clinical laboratorial and/or imaging evidence of obstruction at the anastomosis level, after it was considered completely treated, requiring subsequent interventional procedure.

RESULTS: A total of 195 post-OLT patients were assessed for eligibility. One hundred and sixty-four (164) patients were diagnosed with anastomotic biliary stricture. ERCP was successfully performed in 157/164 (95.7%) patients with AS, that were treated with either multiple plastic (n = 109) or metallic billiary stents (n = 48). Mean treatment duration, number of procedures and stents required were lower in the metal stent group. Acute pancreatitis was the most common procedure related complication, occurring in 17.1% in the covered self-expandable metal stents (cSEMS) and 4.1% in the multiple plastic stent (MPS) group. Migration was the most frequent stent related complication, observed in 4.3% and 5.5% (cSEMS and MPS respectively). Stricture resolution was achieved in 86.8% in the cSEMS group and in 91% in MPS group. Stricture recurrence after a median follow up of 20 mo was observed in 10 (30.3%) patients in the cSEMS and 7 (7.7%) in the plastic stent group, a statistically significant difference (P = 0.0017). Successful stricture resolution after secondary treatment was achieved in 66.6% and 62.5% of patients respectively in the cSEMS and plastic stents groups.

CONCLUSION: Multiple plastic stents are currently the first treatment option for AS in patients with duct-to-duct anastomosis. cSEMS was associated with increased pancreatitis risk and higher recurrence rate.

Use of stents in treatment of malignant biliary obstruction

Stents are now recognized as the first choice of palliative therapy for malignant biliary obstruction. Since stents can effectively relieve obstruction, reduce jaundice, and improve the quality of life, their usage in inoperable biliary tract cancer patients has broad prospects. This paper reviews the use of stents in the treatment of malignant biliary obstruction with regards to stent type, selection, placement and the combination of stenting with other means of treatment.

Covered self-expanding metal stents may be preferable to plastic stents in the treatment of chronic pancreatitis-related biliary strictures: a systematic review comparing 2 methods of stent therapy in benign biliary strictures

BACKGROUND

Covered self-expanding metal stents (CSEMS) are being increasingly used in the endoscopic treatment of benign biliary strictures (BBS). There is no solid evidence yet to support their routine use.

GOALS

To evaluate feasibility, success rate, and complications of CSEMS compared with multiple plastic stents (PS) in BBS in a systematic review.

STUDY

A systematic search of electronic databases (Medline, Scopus, and Embase) for studies published from 2000 to 2012 combined to hand-search of reference lists resulted 4977 articles. Out of 99 potentially relevant studies selected for full-text review, 12 CSEMS (376 patients) and 13 PS studies (570 patients) met the final inclusion criteria. A systematic review comparing the 2 methods was made using proportion meta-analysis.

RESULTS

A tendency to successful use of CSEMS in strictures related to chronic pancreatitis (CP) was shown: clinical success of 77% and 33% [95% confidence interval (CI), 61%-94% vs. 4%-63%, P=0.06] was achieved with CSEMS and PS at 12 months follow-up, respectively. There were no differences in the success rates of other etiologies except CP or in the early complications. In CSEMS, incidence of late adverse events was lower in CP-related strictures (3% vs. 67%, 95% CI, 0%-13% vs. 17%-99%, P=0.02). The median number of endoscopic retrograde cholangiopancreatographies was lower with CSEMSs: 1.5 versus 3.9 (P=0.002).

CONCLUSIONS

Improved clinical success with fewer endoscopic sessions and corresponding complication rate may be achieved with CSEMS treatment compared with PS in BBS secondary to CP. In other BBS etiologies, this systematic review remains inconclusive.

Covered self-expandable metal stents with an anti-migration system improve patency duration without increased complications compared with uncovered stents for distal biliary obstruction caused by pancreatic carcinoma: a randomized multicenter trial

OBJECTIVES

The requirements of biliary stents used in the palliation of malignant biliary obstruction are a long duration of patency and minimal adverse effects. Covered self-expandable metal stents (SEMSs) have been shown to prevent tumor ingrowth, which is the most frequent complication of uncovered SEMSs. However, because they are prone to migration, the superiority of covered SEMS has yet to be convincingly demonstrated. The aim of this study was to evaluate the superiority of covered over uncovered SEMSs in the palliation of distal biliary obstruction due to unresectable pancreatic carcinoma, using both stent types with relatively low axial force and uncovered flared ends to prevent their migration.

METHODS

From April 2009 to December 2010, 120 patients who were admitted to 22 tertiary-care centers because of distal biliary obstruction from unresectable pancreatic carcinomas were enrolled in this prospective randomized multicenter study. Patients were randomly assigned to receive a covered or uncovered SEMS deployed at the site of the biliary stricture during endoscopic retrograde cholangiopancreatography. Stent patency time, patient survival time, patient survival time without stent dysfunction (time to stent dysfunction or patient death), cause of stent dysfunction (ingrowth, overgrowth, migration, or sludge formation), and serious adverse events were compared between covered and uncovered SEMS groups.

RESULTS

Patient survival time in the two groups did not significantly differ (median: 285 and 223 days, respectively; P=0.68). Patient survival time without stent dysfunction was significantly longer in the covered than in the uncovered SEMS group (median: 187 vs. 132 days; P=0.043). Stent patency was also significantly longer in the covered than in the uncovered SEMS group (mean±s.d.: 219.3±159.1 vs. 166.9±124.9 days; P=0.047). Reintervention for stent dysfunction was performed in 14 of 60 patients with covered SEMSs (23%) and in 22 of 60 patients with uncovered SEMSs (37%; P=0.08). Stent dysfunction was caused by tumor ingrowth, tumor overgrowth, and sludge formation in 0 (0%), 3 (5%), and 11 (18%) patients in the covered SEMSs group, and in 15 (25%), 2 (3%), and 6 (10%) patients in the uncovered SEMSs group, respectively. Stent migration was not observed in either group. Rates of tumor overgrowth and sludge formation did not significantly differ between the two groups, whereas the rate of tumor ingrowth was significantly lower in the covered than in the uncovered SEMS group (P<0.01). Acute pancreatitis occurred in only one patient in the covered SEMS group. Acute cholecystitis occurred in one patient in the covered SEMS group and in two patients in the uncovered SEMS group. There was no significant difference between the two groups in the incidence of serious adverse events.

CONCLUSIONS

By preventing tumor ingrowth and migration, covered SEMSs with an anti-migration system had a longer duration of patency than uncovered SEMSs, which recommends their use in the palliative treatment of patients with biliary obstruction due to pancreatic carcinomas.

Endoscopic Removal of a Proximally Migrated Metal Stent during Balloon Sweeping after Stent Trimming

Placement of a self-expanding metal stent (SEMS) is an effective method for palliation of a malignant biliary obstruction. However, metal stents can cause various complications, including stent migration. Distally migrated metal stents, particularly covered SEMS, can be removed successfully in most cases. Stent trimming using argon plasma coagulation may be helpful in difficult cases despite conventional methods. However, no serious complications related to the trimming or remnant stent removal method have been reported due to the limited number of cases. In particular, proximal migration of a remnant fragmented metal stent after stent trimming followed by balloon sweeping has not been reported. We report an unusual case of proximal migration of a remnant metal stent during balloon sweeping following stent trimming by argon plasma coagulation. The remnant metal stent was successfully removed with rotation technique using a basket and revised endoscopically.

Biliary stent therapy for dominant strictures in patients affected by primary sclerosing cholangitis

The diagnosis and the treatment of dominant strictures (DS) in patients with primary sclerosing cholangitis (PSC) is challenging and the scientific literature on the subject is quite limited. Only level II and level III evidence is available to guide physicians managing patients with DS and PSC. For the diagnosis, intraductal endoscopic ultrasound is the most sensitive (64%) and specific (95%) test. However, the majority of cases require a combination of several different diagnostic tests, as there is no single investigation that can rule out malignancy in this group of patients. For the treatment, serial endoscopic or percutaneous dilatations provide 1- and 3-year biliary duct patency in 80 and 60% of patients, respectively. Dilatation and stenting are the most common interventions, although the optimal duration of treatment has still not been clearly defined. Bile duct resection and/or bilioenteric bypass are currently indicated only for patients with preserved liver function. For all other patients, benign DS can be treated with endoscopic dilatation with short-term stenting. This approach is effective and safe and does not increase the risk of malignant transformation or complications for liver transplant candidates. During the last decade, the use of self-expandable metallic stents for benign diseases has become an innovative option. The aim of this article is to review the diagnostic and therapeutic strategies for patients affected by PSC and DS with specific emphasis on the outcomes of patients treated with temporary stents.

Endoscopic retrograde cholangiopancreatography for distal malignant biliary stricture

Endoscopic biliary stent placement is widely accepted as palliation for malignant biliary obstruction or as a treatment of benign biliary stricture. Although various biliary stent designs have become available since self-expandable metallic stents were introduced, no single ideal stent has been developed. An ideal stent should be patent until death, or surgery, in patients with resectable malignant biliary obstruction. Fewer complications, maneuverability, cost-effectiveness, and removability are also important factors. Alternatively, should we develop a novel method for biliary drainage other than biliary stenting via endoscopic retrograde cholangiopancreatography? This article reviews the current status of biliary stenting for malignant biliary obstructions.

Biliary leak in post-liver-transplant patients: is there any place for metal stent?

Objectives. Endoscopic management of bile leak after orthotopic liver transplant (OLT) is widely accepted. Preliminary studies demonstrated encouraging results for covered self-expandable metal stents (CSEMS) in complex bile leaks. Methods. Thirty-one patients with post-OLT bile leaks underwent endoscopic temporary placement of CSEMS (3 partially CSEMS , 18 fully CSEMS with fins and 10 fully CSEMS with flare ends) between December 2003 and December 2010. Long-term clinical success and safety were evaluated. Results. Median stent indwelling and follow-up were 89 and 1,353 days for PCSEMS, 102 and 849 for FCSEMS with fins and 98 and 203 for FCSEMS with flare ends. Clinical success was achieved in 100%, 77.8%, and 70%, respectively. Postplacement complications: cholangitis (1) and proximal migration (1), both in the FCSEMS with fins. Postremoval complications were biliary strictures requiring drainage: PCSEMS (1), FCSEMS with fins (6) and with flare ends (1). There was no significant differences in the FCSEMS groups regarding clinical success, age, gender, leak location, previous treatment, stent indwelling, and complications. Conclusion. Temporary placement of CSEMS is effective to treat post-OLT biliary leaks. However, a high number of post removal biliary strictures occurred especially in the FCSEMS with fins. CSEMS cannot be recommended in this patient population.

Role of fully covered self-expandable metal stent for treatment of benign biliary strictures and bile leaks

Endoscopic therapy by balloon dilation and placement of multiple large-bore plastic stents is the treatment of choice for benign biliary stricture. This approach is effective but it typically requires multiple endoscopic sessions given the short duration of stent patency. The endoscopic approach for treatment of bile leak involves the placement of a stent with or without biliary sphincterotomy. The self-expandable metal stent (SEMS) has traditionally been used for palliation of malignant biliary strictures given the long duration of stent patency owing to their larger stent diameter. Recently, SEMS has been used in a variety of benign biliary strictures and leaks, especially with the design of the covered self-expandable metal stent (CSEMS), which permits endoscopic-mediated stent removal. The use of CSEMS in benign biliary stricture could potentially result in a decrease in endoscopic sessions and it is technically easier when compared to placement of multiple plastic stents. However, complications such as cholecystitis due to blockage of cystic duct, stent migration, infection and pancreatitis have been reported. The potential subsegmental occlusion of contralateral intrahepatic ducts also limits the use of CSEMS in hilar stricture. Certain techniques and improvement of stent design may overcome these challenges in the future. Thus, CSEMS may be appropriate in only highly selected conditions, such as refractory benign biliary stricture, despite multiple plastic stent placement or difficult to treat bile duct stricture from chronic pancreatitis, and should not be used routinely. This review focuses on the use of fully covered self-expandable metal stent for benign biliary strictures and bile leaks.

Use of fully covered self-expanding metal stents in benign biliary diseases

Biliary fully covered self-expanding metal stents (FCSEMS) are now being used to treat several benign biliary conditions. Advantages include small predeployment and large postexpansion diameters in addition to an easy insertion technique. Lack of imbedding of the metal into the bile duct wall enables removability. In benign biliary strictures that usually require multiple procedures, despite the substantially higher cost of FCSEMS compared with plastic stents, the use of FCSEMS is offset by the reduced number of endoscopic retrograde cholangiopancreatography interventions required to achieve stricture resolution. In the same way, FCSEMS have also been employed to treat complex bile leaks, perforation and bleeding after endoscopic biliary sphincterotomy and as an aid to maintain permanent drainage tracts obtained by means of Endoscopic Ultrasound-guided biliary drainage. Good success rates have been achieved in all these conditions with an acceptable number of complications. FCSEMS were successfully removed in all patients. Comparative studies of FCSEMS and plastic stents are needed to demonstrate efficacy and cost-effectiveness

Self-expandable metal stents in malignant biliary obstruction

Malignant biliary obstruction can be due to direct tumor infiltration, extrinsic compression, adjacent inflammation, desmoplastic reaction from tumors or, more commonly, a combination of the above factors. Pancreatic cancer is the most common cause of malignant biliary obstruction, and jaundice occurs in 70-90% of the patients during the course of the disease. Compared with the uncovered metal stents, covered metal stents have longer patency and a lower rate of tumor ingrowth, but have a higher rate of stent migration. To combat the occlusion and provide an antitumor effect, drug-eluting stents were developed. A duodenal stricture complicates biliary stent placement in 10-20% of patients with distal biliary obstruction due to pancreatic cancer. When both strictures are considered, a biliary stent can be placed either preceding or following duodenal stent placement. Complications of self-expandable metal stents include stent occlusion, stent migration, cholecystitis and pancreatitis.

Meta-analysis of randomized trials comparing the patency of covered and uncovered self-expandable metal stents for palliation of distal malignant bile duct obstruction

BACKGROUND

Self-expandable metal stents (SEMSs) are used for palliation of malignant biliary obstruction.

OBJECTIVE

We performed a meta-analysis to compare stent patency and stent survival of covered SEMSs (CSEMSs) and uncovered SEMSs (USEMSs) in patients with unresectable distal malignant biliary obstruction.

DESIGN

Meta-analysis.

SETTING

Tertiary-care facility.

PATIENTS

A comprehensive search of several databases (from each database's earliest inclusive dates to November 2010, any language, and any population) was conducted. The search identified 337 potential abstracts and titles, of which 16 were retrieved in full text. Review of references identified 17 additional studies. We found 5 multicenter, randomized trials involving 781 patients.

INTERVENTION

Placement of covered and uncovered SEMSs for treatment of distal malignant biliary obstruction.

MAIN OUTCOME MEASUREMENTS

Stent patency, stent survival, patient survival, and cause for stent dysfunction (ingrowth, overgrowth, migration, and sludge formation).

RESULTS

The median length of follow-up was 212 days. Compared with USEMSs, CSEMSs were associated with significantly prolonged stent patency (weighted mean difference [WMD] 60.56 days; 95% confidence interval [CI], 25.96, 95.17; I² = 0%) and longer stent survival (WMD 68.87 days; 95% CI, 25.64, 112.11; I(2) = 79%). Stent migration, tumor overgrowth, and sludge formation were significantly higher with CSEMSs (relative risk [RR] 8.11; 95% CI, 1.47, 44.76; I² = 0%), (RR 2.02; 95% CI, 1.08, 3.78; I² = 0%), (RR 2.89; 95% CI, 1.27, 6.55; I² = 0%).

LIMITATIONS

Relatively low number of studies available and the fact that 2 of the 5 studies were from one institution. Also, the limited availability of some stents used in the trials may limit the applicability of these results.

CONCLUSION

CSEMSs have a significantly longer duration of patency compared with USEMSs in patients with distal malignant biliary obstruction. Stent dysfunction occurs at a similar rate, although there is a trend toward later obstruction with CSEMSs.

Self-expandable metal stents for malignant distal biliary strictures

Obstructive jaundice can result from benign or malignant etiologies. The common benign conditions include primary sclerosing cholangitis, chronic pancreatitis, and gallstones. Malignant biliary obstruction can be caused by direct tumor infiltration, extrinsic compression by enlarged lymph nodes or malignant lesions, adjacent inflammation, desmoplastic reaction from a tumor, or a combination of these factors. Malignant diseases causing biliary obstruction include pancreatic cancer, ampullary cancer, cholangiocarcinoma, and metastatic diseases. This article focuses on malignant distal biliary obstruction and its management.

Fully covered self-expanding metal stents placed temporarily in the bile duct: safety profile and histologic classification in a porcine model

BACKGROUND

Fully covered Self-Expanding metal stents (FCSEMS) have been shown efficacious in palliating malignant biliary obstructions. There is little data analyzing mucosal response to their temporary placement in the bile duct.

METHODS

Ten mini pigs underwent endoscopic placement of a FCSEMS (Wallflex, Boston Scientific). FCSEMS were kept in place for three months. At the end of the 3 months, FCSEMS were removed endoscopically. Five pigs were euthanized and their bile ducts harvested. The other five were kept alive for another month post removal. A single pathologist, created a scoring system (to determine degree of inflammation, fibrosis, and epithelial injury), examined all specimens in a blinded fashion.

RESULTS

Four FCSEMS spontaneously migrated in the duodenum. On post mortem examination, mild mucosal thickness was noted in three bile duct specimens while superficial inflammation of the bile duct was noted in five animals. Histologic examination of the bile duct revealed focal acute inflammation in both groups. For the 5 animals euthanized immediately after stent removal, there was a tendency to have superficial mucosal erosion and fibrosis. In contrast, increased chronic inflammation was more commonly seen in the animals 1 month post stent removal, with all animals in this group showing moderate degrees of mononuclear inflammatory cell mucosal infiltrates. No severe inflammatory or fibrotic duct injury was observed in any of the study animals, with degree of injury graded as mild to moderate.

CONCLUSION

FCSEMS appear to induce minimal tissue overgrowth or fibrosis post placement. Ease of removability and no significant histologic injury are advantages noted with FCSEMS., however, further studies are needed to evaluate treating benign biliary strictures with FCSEMS in humans.

Fully-covered, self-expandable metal stents (CSEMS) in malignant distal biliary strictures: mid-term evaluation

BACKGROUND AND AIMS

Limited data exist regarding fully-covered, self-expandable metal stents (CSEMS) with anchoring fins for the management of malignant distal biliary strictures. The aim of this study is to evaluate their safety and patency.

METHODS

Over a period of 2 years, 70 patients (45 males, 66 ± 13 years) underwent endoscopic retrograde cholangiopancreatography (ERCP) with placement of a 10-mm (67 patients) or 8-mm diameter (3 patients) CSEMS for the palliation of distal malignant biliary obstruction (pancreatic [53] or other [17]). Data were collected prospectively for survival and stent patency; complications were evaluated retrospectively.

RESULTS

After CSEMS placement, 17 patients proceeded to surgery, and 53 patients were deemed unresectable. Mean survival for non-surgical candidates was 180 days (range: 15-1091), and 170 days (range: 9-589) for patients who underwent surgical management. CSEMS were left in place and remained patent for a mean of 163 days (range: 15-1091) in non-surgical candidates, and a mean of 55 days (range: 5-126) in surgical candidates. Complications during placement included wire perforations (4) and proximal deployment requiring repositioning (4), one of which was complicated by a bile leak. Post-procedure complications were observed in 24 cases (34%) and included post-ERCP pancreatitis (8, with 2 of them severe), post-procedure pain (5, with 3 requiring admission), cholecystitis (3), stent occlusion (3), cholangitis (2), proximal migration (1), post-sphincterotomy bleeding (1), and sepsis leading to death (1).

CONCLUSION

CSEMS appear to provide acceptable short-term patency rates; however, their limited long-term patency and high complication rate might limit their widespread use. Further long-term prospective data are required to confirm this observation.

Covered self-expandable metal stents for benign biliary tract diseases

PURPOSE OF REVIEW

Benign biliary diseases are often managed endoscopically using plastic stents. Benign biliary strictures (BBS) respond to placement of multiple large-bore plastic stents, though requiring multiple procedures to place stents, and to exchange stents to prevent and/or treat stent occlusion. Bile leaks close using plastic stents, which divert bile away from the leak into the duodenum. Covered self-expandable metal stents (CSEMS), intended for palliation of malignant biliary obstruction, have been used to treat benign biliary diseases. Advantages include small predeployment and large postexpansion diameters. Lack of imbedding of the metal into the bile duct wall enables removability.

RECENT FINDINGS

For strictures, one CSEMS is inserted without need for dilation and remains in place for up to 6 months. Successful removal has been reported in all cases. Long-term stricture resolution is achieved in up to 92%. Adverse events include migration and new stricture formation. For treatment of complex bile leaks, the covering and large diameter allow successful closure in nearly all cases. Other uses of CSEMS include treatment of postsphincterotomy bleeding and closure of perforations.

SUMMARY

CSEMS show promise for treatment of BBS and complex biliary leaks. Successful resolution can be achieved in the majority of patients with the advantage of fewer procedures, which offsets their higher cost.

Anchoring flap versus flared end, fully covered self-expandable metal stents to prevent migration in patients with benign biliary strictures: a multicenter, prospective, comparative pilot study (with videos)

BACKGROUND

Recently, placement of fully covered self-expandable metal stents (FCSEMSs) has been proposed as an alternative treatment for the management of benign biliary strictures. However, the major limitations of FCSEMSs are frequent migration and removal complications.

OBJECTIVE

We conducted this study to compare the antimigration effects, complication rates, and short-term efficacy of 2 FCSEMSs with either an anchoring flap (AF) or a flared end (FE) at the proximal end of the stent.

DESIGN

A multicenter, prospective comparative pilot study.

SETTING

Two tertiary referral centers.

PATIENTS

A total of 43 patients with benign biliary stricture who were candidates for placement of FCSEMSs were assigned to the AF (n = 22) or the FE group (n = 21).

INTERVENTIONS

Predefined duration of placement and removal of FCSEMSs.

RESULTS

After a median period of placement of 6 months (interquartile range 4-6), no patients in the AF group and 33% of patients (7 of 21, 1 in proximal and 6 in distal) in the FE group had stent migration (P = .004). The removal rate of the FCSEMSs was 100% in both groups (per protocol, n = 22 in the AF group and n = 17 in the FE group). Immediate improvement of biliary stricture was 91% (20/22, per protocol) in the AF group and 88% (15/17, per protocol) in the FE group. All stents were removed without difficulty.

LIMITATIONS

Short-term follow-up after the removal of FCSEMSs.

CONCLUSIONS

With regard to the antimigration effect of FCSEMSs for benign biliary stricture, the AF design may be superior to the FE. For up to 6 months, both FCSEMSs can be endoscopically removed without complications. (

CLINICAL TRIAL REGISTRATION NUMBER

NCT00945516.).

Advances in pancreatobiliary endoscopy

PURPOSE OF REVIEW

The role of diagnostic and therapeutic endoscopic retrograde cholangiopancreatography (ERCP) continues to mature. We will review the progress of pancreatobiliary endoscopy in the evaluation and treatment of benign and malignant pancreatobiliary diseases.

RECENT FINDINGS

First, minimizing contrast injection of the pancreas, wire-guided cannulation and prophylactic pancreatic stenting have been re-emphasized in recent studies as the most important endoscopic interventions that can lower the risk of post-ERCP pancreatitis. The role of preoperative ERCP in patients with jaundice secondary to pancreatic cancer was raised in a randomized trial; the widespread use of preoperative biliary drainage is now up for debate. The use of ERCP, intraoperative cholangiography, endoscopic ultrasound and magnetic resonance cholangiopancreatography in the evaluation of suspected common bile duct stones is discussed. We conclude by evaluating studies of fully covered, self-expandable metallic stents, with an emphasis on their potential use in benign biliary disease.

SUMMARY

Given the risk of complications and development of alternative imaging modalities, diagnostic ERCP is rarely indicated. However, therapeutic ERCP has been bolstered by advances such as fully covered metallic stents and cholangioscopy.

Percutaneous palliation of pancreatic head cancer: randomized comparison of ePTFE/FEP-covered versus uncovered nitinol biliary stents

The purpose of this study was to compare the clinical effectiveness of expanded polytetrafluoroethylene/fluorinated-ethylene-propylene (ePTFE/FEP)-covered stents with that of uncovered nitinol stents for the palliation of malignant jaundice caused by inoperable pancreatic head cancer. Eighty patients were enrolled in a prospective randomized study. Bare nitinol stents were used in half of the patients, and ePTFE/FEP-covered stents were used in the remaining patients. Patency, survival, complications, and mean cost were calculated in both groups. Mean patency was 166.0 ± 13.11 days for the bare-stent group and 234.0 ± 20.87 days for the covered-stent group (p = 0.007). Primary patency rates at 3, 6, and 12 months were 77.5, 69.8, and 69.8% for the bare-stent group and 97.5, 92.2, and 87.6% for the covered-stent group, respectively. Mean secondary patency was 123.7 ± 22.5 days for the bare-stent group and 130.3 ± 21.4 days for the covered-stent group. Tumour ingrowth occurred exclusively in the bare-stent group in 27.5% of cases (p = 0.002). Median survival was 203.2 ± 11.8 days for the bare-stent group and 247.0 ± 20 days for the covered-stent group (p = 0.06). Complications and mean cost were similar in both groups. Regarding primary patency and ingrowth rate, ePTFE/FEP-covered stents have shown to be significantly superior to bare nitinol stents for the palliation of malignant jaundice caused by inoperable pancreatic head cancer and pose comparable cost and complications. Use of a covered stent does not significantly influence overall survival rate; nevertheless, the covered endoprosthesis seems to offer result in fewer reinterventions and better quality of patient life.

Early infectious complications of percutaneous metallic stent insertion for malignant biliary obstruction

OBJECTIVE

This study was designed to evaluate predisposing factors for early infectious complications after percutaneous metallic biliary stent insertion in patients with malignant biliary obstruction.

MATERIALS AND METHODS

From August 1999 to June 2008, 215 consecutively registered patients with inoperable malignant biliary obstruction were treated with percutaneous placement of a metallic stent. The incidence of early infectious complications was evaluated. Sex, age, level of obstruction, type and number of stents, and stent position (across or above the main duodenal papilla) were retrospectively reviewed. The findings in patients with early infectious complications were compared with those in patients without early infectious complications.

RESULTS

Infectious complications occurred within 30 days after stent placement in 14 of 215 (6.5%) patients. Univariate analysis showed a significant difference between the two groups with respect to nontranspapillary stent placement (p=0.003). In the multiple logistic regression analysis, age, sex, level of obstruction, and type and number of stents were negatively associated with the development of early infectious complications (p>0.05).

CONCLUSION

Our study data showed that stent placement across the main duodenal papilla seemed to prevent early infectious complications after percutaneous metallic biliary stent insertion in patients with malignant biliary obstruction.