Preliminary results of a new covered biliary metal stent for malignant biliary obstruction

Fully covered versus partially covered self-expandable metal stents for palliation of distal malignant biliary obstruction: a systematic review and meta-analysis

BACKGROUND AND AIMS

Self-expandable metal stents (SEMSs) are standardly used for distal malignant biliary obstruction (dMBO). Although data suggest that covered versus uncovered SEMSs increase the time to recurrent biliary obstruction (TRBO), no data are available for fully covered (FC) versus partially covered (PC) designs.

METHODS

PubMed, Scopus, and Cochrane databases were screened up to January 2023 for studies concerning dMBO treated by an FC- or PC-SEMS and describing adverse events (AEs), recurrences, or TRBO for specific design subpopulations. Pooled proportions or means were calculated using a random-effects model. Several subanalyses were preplanned, including a subanalysis restricted to prospective studies and unresectable diseases. Heterogeneity and publication bias were explored. Standardized differences (d-values) were calculated between groups.

RESULTS

From 1290 records, 62 studies (3327 using FC-SEMSs and 2322 using PC-SEMSs) were included. FC- versus PC-SEMSs showed negligible differences in the rate of total AEs (12% vs 9.9%) and all specific AEs, including cholecystitis (2.5% vs 2.6%). In a subanalysis restricted to prospective studies and unresectable diseases, the rate of RBO was comparable between FC-SEMSs (27.3% [95% confidence interval {CI}, 23.7-31.2], I2 = 35.34%) and PC-SEMSs (25.3% [95% CI, 20.2-30.7], I2 = 85.09%), despite small differences (d-values between .186 and .216) in the rate of ingrowth (.5% vs 2.9%) favoring FC-SEMSs and migration (9.8% vs 4.3%) favoring PC-SEMSs. TRBO was shorter for FC-SEMSs (238 days [95% CI, 191-286], I2 = 63.1%) versus PC-SEMSs (369 days [95% CI, 290-449], I2 = 71.9%; d-value = .116).

CONCLUSIONS

Despite considerable heterogeneity and small standardized differences, PC-SEMSs consistently exhibited longer TRBO than FC-SEMSs across analyses, without any other differences in AE rates, potentially proposing PC-SEMSs as the standard comparator and TRBO as the primary outcome for future randomized studies on dMBO. (Clinical trial registration number: CRD42023393965.).

Prevention of pancreatitis after stent implantation for distal malignant biliary strictures: systematic review and meta-analysis

INTRODUCTION

Biliary stent placement remains a palliative treatment for patients with unresectable distal malignant biliary strictures (DMBS). The incidence of post-ERCP-pancreatitis (PEP) significantly increases in patients receiving fully covered self-expandable metal stents (FCSEMS) who undergo endoscopic retrograde cholangiopancreatography (ERCP).

AREAS COVERED

This review provides an overview of prevention of PEP after stent implantation for DMBSs. The following operational variables were evaluated: (1) stent type (plastic or metal stent); (2) stent location (above or across the sphincter of Oddi); (3) prophylactic pancreatic duct stent placement; (4) endoscopic sphincterotomy (EST). PubMed, EMBASE, and Cochrane database were searched to identify eligible studies up to October 2021. The odds ratio (OR) with 95% confidence intervals (CI) were pooled using fixed- or random- effects models.

EXPERT OPINION

1. PEP occurs more frequently in DMBS patients with self-expandable metal stents (SEMS) compared to that plastic stent (PS). 2. The PEP incidence is higher in covered stents than that in uncovered self-expandable metal stents (USEMS), but not significantly. 3. PEP incidence increases in patients receiving transpapillary FCSEMS placement, particularly when there is an absence of pancreatic duct dilation, and prophylactic pancreatic stenting is recommended for these patients. 4. Limited studies with small sample indicate that there is no significant difference in PEP incidence between transpapillary and suprapapillary stents placement for DMBS. 5. Limited studies indicate that EST does not significantly affect the incidence of pancreatitis in DMBS patients.

Recent Advances in Manufacturing Innovative Stents

Cardiovascular diseases are the most distributed cause of death worldwide. Stenting of arteries as a percutaneous transluminal angioplasty procedure became a promising minimally invasive therapy based on re-opening narrowed arteries by stent insertion. In order to improve and optimize this method, many research groups are focusing on designing new or improving existent stents. Since the beginning of the stent development in 1986, starting with bare-metal stents (BMS), these devices have been continuously enhanced by applying new materials, developing stent coatings based on inorganic and organic compounds including drugs, nanoparticles or biological components such as genes and cells, as well as adapting stent designs with different fabrication technologies. Drug eluting stents (DES) have been developed to overcome the main shortcomings of BMS or coated stents. Coatings are mainly applied to control biocompatibility, degradation rate, protein adsorption, and allow adequate endothelialization in order to ensure better clinical outcome of BMS, reducing restenosis and thrombosis. As coating materials (i) organic polymers: polyurethanes, poly(ε-caprolactone), styrene-b-isobutylene-b-styrene, polyhydroxybutyrates, poly(lactide-co-glycolide), and phosphoryl choline; (ii) biological components: vascular endothelial growth factor (VEGF) and anti-CD34 antibody and (iii) inorganic coatings: noble metals, wide class of oxides, nitrides, silicide and carbide, hydroxyapatite, diamond-like carbon, and others are used. DES were developed to reduce the tissue hyperplasia and in-stent restenosis utilizing antiproliferative substances like paclitaxel, limus (siro-, zotaro-, evero-, bio-, amphi-, tacro-limus), ABT-578, tyrphostin AGL-2043, genes, etc. The innovative solutions aim at overcoming the main limitations of the stent technology, such as in-stent restenosis and stent thrombosis, while maintaining the prime requirements on biocompatibility, biodegradability, and mechanical behavior. This paper provides an overview of the existing stent types, their functionality, materials, and manufacturing conditions demonstrating the still huge potential for the development of promising stent solutions.

Safety, efficacy, and removability of a fully covered multi-hole metal stent in a swine model of hilar biliary stricture: a feasibility study

Background and study aims  Use of fully covered self-expandable metal stents (FCSEMS) for biliary drainage of malignant hilar biliary strictures is limited because of risk of cholangitis due to side branch obstruction. The aim of this study was to evaluate the safety and efficacy of unilateral placement of a multi-hole FCSEMS (FCSEMS-MH), which had a 2.5-mm hole in the center of the membrane on each cavity, in a swine model of hilar biliary stricture. Materials and methods  Six female mini pigs were included in this prospective study. The hilar biliary stricture model was prepared using an endobiliary radiofrequency ablation. FCSEMS-MHs were endoscopically inserted into the peri-hilar bile duct of all the animals. Outcomes were assessed in terms of adverse events (AEs) including cholangitis, stent patency, stent migration, and endoscopic stent removability for 1 month after stenting. Results  In terms of hilar biliary stricture types, two animals were of Bismuth type I and four were of type II. Technical success rate for endoscopic metal stenting was 100 % (6/6), and the functional success rate, which was evaluated 7 days after stent insertion, was also 100 % (5/5). The immediate overall AE rate was 0 %. There was no procedure-related mortality and stent migration did not occur in any animal during the 4-week stent indwelling period. Stents were removed from all six animals at 4 weeks post-stenting. Conclusion  Unilateral placement of FCSEMS-MH might be safe and effect for swine hilar biliary stricture models. However, long-term follow-up and comparative studies are needed to verify the usefulness of this stent.

A Double-Layered Covered Biliary Metal Stent for the Management of Unresectable Malignant Biliary Obstruction: A Multicenter Feasibility Study

Background/Aims

The covered self-expandable metal stent (CMS) was developed to prevent tumor ingrowth-induced stent occlusion during the treatment of malignant biliary obstruction. However, complications such as cholecystitis, pancreatitis, and stent migration can occur after the endoscopic insertion of CMSs. The aim of the present study was to assess the efficacy and safety of a double-layered CMS (DCMS) for the management of malignant bile duct obstruction.

Methods

DCMSs were endoscopically introduced into 59 patients with unresectable malignant extrahepatic biliary obstruction at four tertiary referral centers, and the patient medical records were retrospectively reviewed.

Results

Both the technical and functional success rates were 100%. Procedure-related complications including pancreatitis, cholangitis, stent migration, and liver abscess occurred in five patients (8.5%). The median follow-up period was 265 days (range, 31 to 752 days). Cumulative stent patency rates were 68.2% and 40.8% at 6 and 12 months, respectively. At the final follow-up, the rate of stent occlusion was 33.9% (20/59), and the median stent patency period was 276 days (range, 2 to 706 days).

Conclusions

The clinical outcomes of DCMSs were comparable to the outcomes previously reported for CMSs with respect to stent patency period and complication rates.

Endoscopic palliation of malignant biliary strictures

Malignant biliary strictures often present late after the window for curative resection has elapsed. In such patients, the goal of therapy is typically focused on palliation. While historically, palliative measures were performed surgically, the advent of endoscopic intervention offers minimally invasive options to provide relief of symptoms, improve quality of life, and in some cases, increase survival of these patients. Some of these therapies, such as endoscopic biliary decompression, have become mainstays of treatment for decades, whereas newer modalities, including radiofrequency ablation, and photodynamic therapy offer additional options for patients with incurable biliary malignancies.

Development of Biliary and Enteral Stents by the Korean Gastrointestinal Endoscopists

Stenting in the gastrointestinal tract is a common procedure used for palliation of obstruction in the enteral and biliary tract. Today, stenting of malignant and benign strictures is performed at almost every major tertiary hospital in Korea. Moreover, Korea has become a major global supplier of cutting edge technology in the field of self-expanding metal stents. However, the history of stenting in Korea is relatively short and was far behind that of other nations such as Japan and Germany. The authors are humbled and gratified to have been able to observe the development and application of these stents in Korea, first hand. In this article, the authors review the overall history of stenting with a specific focus on the development of stenting in Korea. The development of esophageal, gastroduodenal, biliary, and colonic stents in Korea are reviewed in this article from a chronological and historical point of view, and a personal account of some of the significant moments of stent development in Korea are described.

Percutaneous transhepatic cholangiography and intraductal radiofrequency ablation combined with biliary stent placement for malignant biliary obstruction

PURPOSE

To determine the safety and feasibility of percutaneous transhepatic cholangiography (PTC) and intraductal radiofrequency (RF) ablation combined with biliary stent placement for malignant biliary obstruction.

MATERIALS AND METHODS

Data from patients with unresectable malignant biliary obstruction who underwent PTC, intraductal RF ablation, and biliary stent placement (n = 12) or PTC and biliary stent placement only (control group; n = 14) were reviewed. Postoperative complications, jaundice remission, and stent patency were assessed.

RESULTS

All procedures were successful. No severe complications (eg, biliary bleeding, perforation) occurred. Two experimental group patients developed cholangitis, which resolved with conservative treatment. The 1-week jaundice remission and 3-month stent patency rates were similar in both groups, but the 6-month stent patency rate was higher in the experimental group (P < .05). In the experimental group, one death occurred as a result of gastrointestinal hemorrhage (unrelated to stent placement) by 3 months, and there were two cases of recurrent jaundice by 6 months. The latter two patients underwent repeat PTC, ablation, and stent placement. In the control group, one death occurred as a result of hepatic failure caused by progressive jaundice at 3 months, and another death resulted from disseminated intravascular coagulation caused by jaundice recurrence at 138 days after stent placement. In addition, seven patients developed jaundice recurrence (50-151 d after stent placement). PTC and repeat stent placement were performed in these patients.

CONCLUSIONS

Percutaneous transhepatic cholangiography and intraductal RF ablation combined with biliary stent placement for malignant biliary obstruction is safe and feasible and effectively prolongs stent patency time.

Percutaneous use of ePTFE/FEP-covered metallic stent for palliation of malignant biliary obstruction

INTRODUCTION

Placement of self-expanding metallic stents has been a standard palliative treatment for patients with inoperable biliary malignancy, aiming at improving quality of life via a minimally invasive procedure. This study aimed to evaluate the efficacy of percutaneous placement of expanded polytetrafluoroethylene/fluorinated ethylene propylene-covered metallic stents for palliation of inoperable biliary malignancy.

MATERIAL AND METHODS

Between February 2012 and April 2013, 11 patients with inoperable malignant biliary obstruction were treated with stent implantation. Serum bilirubin and liver enzyme levels were measured before/immediately after stent placement and at one, three, and six months. Patient survival and stent patency were calculated using Kaplan-Meier analysis.

RESULTS

No migration occurred. Patients showed clinical improvement immediately and one month after stent placement, with a significant reduction in mean serum bilirubin level (p < 0.05). At six months, bilirubin levels were <1.5 mg/dL in all cases. One patient developed acute liver failure four days after stent implantation, leading to death. Survival rates were 90% at three months and 70% at six months. Primary patency rates were 100%, 100%, and 90% at one, three, and six months, respectively.

CONCLUSION

Percutaneous placement of expanded polytetrafluoroethylene/fluorinated ethylene propylene-covered metallic stents offered an effective palliative therapy for patients with inoperable biliary malignancy.

Comparison of the utility of covered metal stents versus uncovered metal stents in the management of malignant biliary strictures in 749 patients

BACKGROUND

Self-expandable metal stents (SEMSs) are used to relieve malignant biliary obstruction.

OBJECTIVE

To compare outcomes between covered self-expandable metal stents (CSEMSs) and uncovered self-expandable metal stents (USEMSs) in malignant biliary obstruction.

DESIGN

Retrospective cohort study.

SETTING

Tertiary cancer center.

PATIENTS

Patients with malignant biliary obstruction.

INTERVENTIONS

Placement of CSEMS or USEMS.

MAIN OUTCOME MEASUREMENTS

Time to recurrent biliary obstruction (TRO), overall survival (OS), and adverse events.

RESULTS

From January 2000 to June 2011, 749 patients received SEMSs: 171 CSEMSs and 578 USEMSs. At 1 year, there was no significant difference in the percentage of patients with recurrent obstruction (CSEMSs, 35% vs USEMSs, 38%) and survival (CSEMSs, 45% vs USEMSs, 49%). There was no significant difference in the median OS (CSEMSs, 10.4 months vs USEMSs, 11.8 months; P = .84) and the median TRO (CSEMSs, 15.4 months vs USEMSs, 26.3 months; P = .61). The adverse event rate was 27.5% for the CSEMS group and 27.7% for the USEMS group. Although tumor ingrowth with recurrent obstruction was more common in the USEMS group (76% vs 9%, P < .001), stent migration (36% vs 2%, P < .001) and acute pancreatitis (6% vs 1%, P < .001) were more common in the CSEMS group.

LIMITATIONS

Retrospective study.

CONCLUSIONS

There was no significant difference in the patency rate or overall survival between CSEMSs and USEMSs for malignant distal biliary strictures. The CSEMS group had a significantly higher rate of migration and pancreatitis than the USEMS group. No significant SEMS-related adverse events were observed in patients undergoing neoadjuvant chemoradiation or surgical resection.

Current status and issues regarding biliary stenting in unresectable biliary obstruction

In the present review, we describe the current status of biliary stenting in patients with unresectable malignant biliary strictures. Self-expandable metallic stents (SEMS) are the ideal biliary stent for both distal and hilar biliary strictures, although in terms of distal biliary strictures, there is still some debate as to the selection of covered or uncovered SEMS, suprapapillary or transpapillary stent placement, side-by-side or stent-in-stent placement, unilateral or bilateral stent placement and the necessity for sphincterotomy. Further high-quality randomized controlled trials for these procedures are warranted.

A comparative study on the efficacy of covered metal stent and plastic stent in unresectable malignant biliary obstruction

Background/Aims

The placement of self expandable metal stent (SEMS) is one of the palliative therapeutic options for patients with unresectable malignant biliary obstruction. The aim of this study was to compare the effectiveness of a covered SEMS versus the conventional plastic stent.

Methods

We retrospectively evaluated 44 patients with unresectable malignant biliary obstruction who were treated with a covered SEMS (21 patients) or a plastic stent (10 Fr, 23 patients). We analyzed the technical success rate, functional success rate, early complications, late complications, stent patency and survival rate.

Results

There was one case in the covered SEMS group that had failed technically, but was corrected successfully using lasso. Functional success rates were 90.5% in the covered SEMS group and 91.3% in the plastic stent group. There was no difference in early complications between the two groups. Median patency of the stent was significantly prolonged in patients who had a covered SEMS (233.6 days) compared with those who had a plastic stent (94.6 days) (p=0.006). During the follow-up period, stent occlusion occurred in 11 patients of the covered SEMS group. Mean survival showed no significant difference between the two groups (covered SEMS group, 236.9 days; plastic stent group, 222.3 days; p=0.182).

Conclusions

The patency of the covered SEMS was longer than that of the plastic stent and the lasso of the covered SEMS was available for repositioning of the stent.

Efficacy of the new double-layer stent for unresectable distal malignant biliary obstruction: a single-center retrospective study

Background and Aims. For distal malignant biliary obstruction in cases with short life expectancy, occlusion of plastic stents (PSs) does not usually occur before death, and the application of such a procedure is considered adequate from the viewpoint of cost-effectiveness. Methods and Setting. A new commercially available DLS with side holes, a conventional DLS, and, uncovered self-expanding metal stents (SEMSs) were retrospectively evaluated in patients with jaundice due to unresectable distal malignant biliary obstruction. Results. A total of 64 patients received endoscopic biliary stenting (23 patients with the new DLS, 24 patients with conventional DLS, and 17 patients with uncovered SEMS) from December 2002 to August 2009. Median patency time was found to be 198 days for the new DLS group and 99 days for the conventional DLS group, revealing a significant difference between devices. There was, however, no significant difference in median patency time between the new DLS and the uncovered SEMS (198 days versus 344 days). Conclusion. The new DLS is efficient and safe and may be considered the first choice for unresectable distal malignant obstruction in cases with short life expectancy.

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.

Safety evaluation of self-expanding metallic biliary stents eluting gemcitabine in a porcine model

BACKGROUND AND AIM

Palliative biliary decompression by metal stent is the treatment of choice for unresectable malignant biliary obstruction; however, conventional stents provide only mechanical palliation and exert no anti-tumor effects. Gemcitabine (GEM) has been reported to be more effective in unresectable pancreatic cancer and biliary cancer compared with other chemotherapeutic drugs. We evaluated the safety of a GEM-eluting stent by analyzing histologic responses of the porcine bile duct.

METHODS

Stents containing GEM (0%, 10%, 15%, and 20% [w/v]) were surgically inserted into bile ducts of pigs (each group, n = 2). The animals were euthanized after 4 weeks, and the stented bile duct segment underwent gross and microscopic examination. Laboratory assay was performed for aspartate transaminase (AST), alanine transaminase (ALT), total bilirubin, and gamma-glutamyl transferase (γ-GTP).

RESULTS

Moderate to severe inflammation was observed in the bile ducts in contact with stents containing 15 and 20% GEM, compared with no inflammation with 0% GEM and mild inflammation with 10% GEM. Fibrous reactions observed in the submucosal layer did not differ among groups. Transmural necrosis and perforations were not observed in any animal. No abnormal laboratory test findings were directly caused by GEM.

CONCLUSION

Our newly developed GEM eluting stents can be used safely in normal bile ducts. Our results indicated that 10% GEM produced mild histologic changes in the stented segment and adjacent tissue; this concentration may be appropriate for clinical application.

Partially covered self-expanding metal stent for unresectable malignant extrahepatic biliary obstruction: results of a large prospective series

BACKGROUND

Endoscopic biliary stenting is a well-established palliative treatment in patients with unresectable malignant biliary strictures. Obstruction of uncovered self-expanding metal stent (SEMS) due to tumor ingrowth is the most frequent complication. Partially covered SEMS might increase stent patency but could favor complications related to stent covering, such as pancreatitis, cholecystitis, and migration. The aim of this study was to evaluate the efficacy and safety of partially covered SEMS in patients with an unresectable malignant biliary stricture.

METHODS

Patients with malignant extrahepatic biliary obstruction treated endoscopically with partially covered SEMS were included in this multicenter, prospective, nonrandomized study.

RESULTS

One hundred ninety-nine patients were endoscopically treated with partially covered SEMS in 32 Spanish hospitals. Clinical success after deep cannulation was 96%. Early complications occurred in 4% (3 pancreatitis, 2 cholangitis, 1 hemorrhage, 1 perforation, and 1 cholecystitis). Late complications occurred in 19.5% (18 obstructions, 10 migrations, 6 cholangitis without obstruction, 3 acute cholecystitis, and 2 pancreatitis), with no tumor ingrowth in any case. Median stent patency was 138.9 ± 112.6 days. One-year actuarial probability of stent patency was 70% and that of nonmigration was 86%. Multivariate analysis showed adjuvant radio- or chemotherapy as the only independent predictive factor of stent patency and previous insertion of a biliary stent was the only predictive factor of migration.

CONCLUSIONS

The partially covered SEMS was easily inserted, had a high clinical success rate, and prevented tumor ingrowth. The incidence of possible complications related to stent coverage, namely, migration, pancreatitis, and cholecystitis, was lower than in previously published series.

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-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.

A multicenter prospective study of the short-term outcome of a newly developed partially covered self-expandable metallic biliary stent (WallFlex(®))

BACKGROUND

Self-expandable metallic stent (SEMS) placement is a widely used, effective therapy for unresectable malignant stricture of the lower bile duct.

AIMS

We evaluated the short-term outcome of the newly developed WallFlex(®) Biliary RX Partially Covered Stent in patients with malignant lower and middle biliary stricture in five tertiary referral centers.

METHODS

The subjects of this study were 52 patients in whom WallFlex(®) Biliary RX Stents were inserted into the bile duct for malignant stenosis of the middle and lower bile duct at five medical facilities between April 2009 and November 2009.

RESULTS

The stent placement success rate was 100%. Effective biliary decompression was achieved in all patients. The incidence of early complications was 7.7% (4/52). Stent occlusion occurred in two patients (3.8%) (one dislocation, one migration); cholecystitis occurred in two patients (3.8%). Neither acute pancreatitis nor stent kinking in the bile duct occurred.

CONCLUSIONS

The present results revealed that the new WallFlex(®) Biliary RX Partially Covered SEMSs were useful for the short-term relief of biliary obstruction due to unresectable distal biliary malignancies.

Endoscopically applied radiofrequency ablation appears to be safe in the treatment of malignant biliary obstruction

BACKGROUND

In unresectable malignant bile duct obstruction in a patient with a life expectancy longer than 3 months, the use of self-expandable metal stents (SEMSs) is the standard technique to ensure continued biliary drainage. As many as 50% of patients with SEMSs will present with stent occlusion within 6 months. Changes to stent design and composition and concomitant therapy have failed to improve stent patency; therefore, alternative techniques to safely prolong stent patency are required.

OBJECTIVE

To demonstrate the safety of endobiliary bipolar radiofrequency ablation (RFA) in patients with malignant biliary obstruction and to report the 90-day biliary patency of this novel procedure.

DESIGN

Open-label pilot study.

SETTING

Single tertiary care unit.

PATIENTS

A total of 22 patients with unresectable malignant bile duct obstruction.

INTERVENTIONS

Bipolar RFA within the bile duct.

MAIN OUTCOME MEASUREMENTS

Immediate and 30-day complications and 90-day stent patency.

RESULTS

A total of 22 patients (16 pancreatic, 6 cholangiocarcinoma) were recruited between January 2009 and April 2010. Deployment of an RFA catheter was successful in 21 patients. SEMS placement was achieved in all cases of successful RFA catheter deployment. One patient failed to demonstrate successful biliary decompression after SEMS placement and died within 90 days. All other patients maintained stent patency at 30 days. One patient had asymptomatic biochemical pancreatitis, 2 patients required percutaneous gallbladder drainage, and 1 patient developed rigors. At 90-day follow-up, 1 additional patient had died with a patent stent, and 3 patients had occluded biliary stents.

LIMITATIONS

Cohort study.

CONCLUSIONS

Endobiliary RFA treatment appears to be safe. Randomized studies with prolonged follow-up are warranted.

Management of complications associated with partially covered biliary metal stents

BACKGROUND

Partially covered metal stents (PCMS) have been increasingly used for both malignant and benign biliary indications. This study reports their complications and subsequent management.

METHODS

Over 5 years, all patients receiving biliary PCMS were followed prospectively until stent-related dysfunction or death. Data were analyzed for the following variables: primary disease, time until revision, and type and reason for revision.

RESULTS

PCMS were placed in 396 patients (247 with malignant biliary strictures and 149 with benign biliary disease). Complications were observed in 70 patients (18%), occurring a mean time following placement of 159 days. Duodenal migration occurred in 27 cases (6.8%), while proximal migration occurred in 9 cases (2.3%). Cholecystitis was documented in 13 cases (3.3%). There were six cases of stent occlusion due to debris or sludge (1.6%), four cases of pancreatitis (1%), four cases of tumor overgrowth (1%), three cases of benign stenosis in the uncovered portion of the PCMS (0.8%), two cases of abdominal pain (0.5%), one case of an infected biloma (0.3%), and one case of a liver abscess (0.3%).

CONCLUSIONS

Major complications associated with PCMS placement include migration and cholecystitis. Their management includes endoscopic revision, cholecystectomy, and gallbladder drainage. Further improvements in the structure and composition of PCMS may prevent these complications.

Efficacy and safety of fully covered self-expandable metallic stents in biliary complications after liver transplantation: a preliminary study

After liver transplantation, the most common biliary complication is the anastomotic stricture, which is followed by biliary leakage. Studies have focused on the endoscopic treatment of biliary complications in transplanted patients with duct-to-duct reconstruction, showing a success rate of 70% to 80% after orthotopic liver transplantation and of 60% after living-related liver transplantation. Once the endoscopic approach fails, surgical treatment with a Roux-en-Y choledochojejunostomy is the sole alternative treatment. The aim of this prospective observational study was to analyze the efficacy and safety of fully covered self-expandable metallic stents for the treatment of posttransplant biliary stenosis and leaks in patients in whom conventional endoscopic retrograde cholangiopancreatography (ERCP) failed. From January 2008 to January 2009, 16 patients met the criteria of endoscopic treatment failure, and instead of surgery, a fully covered stent was placed. All patients had at least 6 months of follow-up (mean follow-up of 10 months). After removal, 14 patients showed immediate resolution of both the biliary stenosis and leak. After a mean of 10 months of follow-up, only 1 patient showed biliary stenosis recurrence. No major complications occurred in any of the patients, except for stent migration in 6 patients, although these presented with no clinical consequences. In conclusion, in patients not responding to standard endoscopic treatment, the placement of fully covered metal stents is a valid alternative to surgery. A cost analysis should be performed in order to evaluate whether to treat transplanted patients suffering from biliary complications with covered self-expandable metallic stent placement as first-line therapy.

Measurement of radial and axial forces of biliary self-expandable metallic stents

BACKGROUND

Efforts to understand the properties of self-expandable metallic stents (SEMSs) through their mechanical properties have progressed. Among them, radial force (RF) is well known as an expanding force, but axial force (AF) has not been measured before. Correlations of these properties to clinical results are not well known.

OBJECTIVE

We measured RF and AF of 14 different SEMSs and discussed the results in terms of clinical implications.

DESIGN

Experimental study.

SUBJECTS

Measurement of RF and AF of 14 different covered and uncovered SEMSs.

METHODS

RF was measured with an RF measurement machine manufactured by Machine Solution, and AF was measured with in-house equipment.

RESULTS

Measurements of RF in the process of expansion showed characteristic patterns closely related to the structures and materials of SEMSs. Results of AF measurement can be classified into 3 groups: high, medium, and low AF, depending on the type of SEMS. AF decreased with an increase of the length of stents. A plot of RF against AF revealed 3 distinguished RF/AF combinations and indicated the importance of understanding the properties by not only RF or AF individually but also by RF/AF combination.

LIMITATIONS

In vitro study using measurement equipment.

CONCLUSION

It was demonstrated that a combination of RF and AF is more effective than RF or AF individually in understanding the clinical implications of SEMSs. More work is needed to correlate mechanical properties with clinical results by designing model experiments.

Covered metallic stents in the management of malignant and benign pancreatobiliary strictures

In the endoscopic management of unresectable malignant biliary obstructions by placement of a metallic stent (MS), longer patency and a lower incidence of stent occlusion are desirable goals. With its mesh structure, the uncovered MS (UMS) is occluded mainly by tumor or tissue ingrowth, making it impossible to remove. The covered MS (CMS) was developed to overcome these disadvantages, and was shown to maintain patency longer than the UMS in our randomized study. The most important characteristic of the CMS is that it is removable, allowing it to be used in patients with resectable malignancies and benign strictures. In addition, the drug-eluting CMS provides an additional approach to the treatment of biliary malignancies. The CMS may also change the treatment paradigm for biliary strictures and strictures due to chronic pancreatitis. The CMS is analogous to a large-bore, expandable plastic stent and is effective both as an endoprosthesis and a dilating or anti-cancer device. However, to better understand the utility of these devices, we need to first consider mechanical properties such as radial force (RF, expansion force) and axial force (AF, straightening force). AF is particularly important when developing CMSs because of related complications.

Management of distal malignant biliary obstruction with the ComVi stent, a new covered metallic stent

BACKGROUND

The covered metallic stent is effective for managing malignant distal biliary obstructions. The most popular covered metallic stent is the covered Wallstent (CWS). This study estimated the efficacy and safety of a new expanded polytetrafluoroethylene (e-PTFE)-covered nitinol metallic stent, the ComVi stent. This covered metallic stent consists of an e-PTFE membrane sandwiched between two uncovered metallic stents with weak axial (straightening) force. Wire is exposed on both the inner and outer surfaces.

METHODS

Between May 2005 and April 2007, ComVi stents were placed consecutively in 47 patients with unresectable malignant distal biliary obstruction. The cases involved 35 pancreatic cancers, 8 metastatic nodes, 2 gallbladder cancers, and 2 bile duct cancers. The patients were compared with 47 patients who received CWS placement between August 2001 and May 2005 matched for age, sex, and causative disease from 133 cases.

RESULTS

No significant differences in stent patency or patient survival were found. Stent occlusion was observed in 13 patients (27.7%) in the ComVi group and 10 patients (21.3%) in the CWS group. The cause of occlusion in both groups was tumor overgrowth (4.25% vs 4.2%), sludge (8.5% vs 6.3%), impaction of food scraps (14.9% vs 2.1%), and bile duct kinking (0% vs 8.4%). Other complications were migration (2.1% vs 17.0%; p = 0.0304) and cholecystitis (2.1% vs 6.3%), and there were significant differences in the incidence of complications except for occlusion (4.2% vs 24.6%; p = 0.0142).

CONCLUSION

The ComVi stent has a patency similar to that of the CWS and a lower incidence of migration. However, early occlusion by food impaction was increased and should be resolved.

Management of occluded uncovered metallic stents in patients with malignant distal biliary obstructions using covered metallic stents

BACKGROUND

Self-expandable metallic stents (EMSs) have been widely used for the palliative treatment of unresectable malignant biliary obstructions, but EMSs are often occluded owing to tumor ingrowth via the wire mesh. Currently, there is no consensus on the management of occluded EMSs. We evaluated the efficacy of a covered EMS as a second endoprosthesis in patients with an occluded EMS.

METHODS

Forty patients with an occluded uncovered EMS (14 men, 26 women; mean age 72 y, range 41 to 89 y) were studied. The patients suffered from the following: pancreatic cancer in 18, bile duct cancer in 11, gallbladder cancer in 5, lymph node metastasis in 4, and papillary cancer in 2. Of these, 26, 7, and 7 were treated with a covered EMS, an uncovered EMS, and a plastic stent (PS), respectively. The second stent was inserted as a stent-in-stent.

RESULTS

The mean patent period for the covered EMS was 220 days, whereas the mean patent periods for the uncovered EMS and plastic stent were 141 and 58 days, respectively. The cumulative patency of the covered EMS group was significantly higher (P=0.0404) than that of the uncovered EMS group. No significant differences in survival were observed between the covered and uncovered groups. No serious complications occurred.

CONCLUSION

Insertion of a covered EMS is an effective and safe treatment for an occluded uncovered EMS.

Temporary placement of covered self-expandable metal stents in benign biliary strictures: a new paradigm? (with video)

BACKGROUND

Benign biliary strictures (BBS) are usually managed with plastic stents, whereas placement of uncovered metallic stents has been associated with failure related to mucosal hyperplasia.

OBJECTIVE

We analyzed the efficacy and safety of temporary placement of a covered self-expanding metal stent (CSEMS) in BBS.

DESIGN

Patients with BBS received temporary placement of CSEMSs until adequate drainage was achieved; confirmed by resolution of symptoms, normalization of liver function tests, and imaging.

SETTING

Tertiary-care center with long-standing experience with CSEMSs.

PATIENTS

Seventy-nine patients with BBS secondary to chronic pancreatitis (32), calculi (24), liver transplant (16), postoperative biliary repair (3), autoimmune pancreatitis (3), and primary sclerosing cholangitis (1).

INTERVENTION

ERCP with temporary CSEMS placement. Removal of CSEMSs was performed with a snare or a rat-tooth forceps.

MAIN OUTCOME MEASUREMENTS

End points were efficacy, morbidity, and clinical response.

RESULTS

CSEMSs were removed from 65 patients. Resolution of the BBS was confirmed in 59 of 65 patients (90%) after a median follow-up of 12 months after removal (range 3-26 months). If patients who were lost to follow-up, developed cancer, or expired were considered failures, then an intent-to-treat global success rate of 59 of 79 (75%) was obtained. Complications associated with placement included 3 post-ERCP pancreatitis (4%), 1 postsphincterotomy bleed (1%), and 2 pain that required CSEMS removal (2%). In 11 patients (14%), the CSEMS migrated. In 1 patient, CSEMS removal was complicated by a bile leak that was successfully managed with plastic stents.

LIMITATION

Pilot study from a single center.

CONCLUSIONS

Temporary CSEMS placement in patients with BBS offers a potential alternative to surgery.

Endoscopic palliation of malignant obstructive jaundice: an evidence-based review

Endoscopic stent insertion is considered the method of choice for palliative treatment of malignant biliary obstruction. Nonetheless, relevant studies are often underpowered or outdated and do not compare actual surgical outcomes with latest stent technology. Purpose of this review was to assess, with an evidence-based methodology, the role of endoscopic versus surgical palliation of patients with malignant obstructive jaundice with special reference to clinical effectiveness, safety aspects and economic outcomes.

A comparison of covered and uncovered Wallstents for the management of distal malignant biliary obstruction

BACKGROUND

The efficacy and complications of covered self-expandable metal stents (SEMS) remain controversial.

OBJECTIVE

We conducted this study to compare the efficacies and complication rates of covered and uncovered SEMS in malignant biliary obstruction.

DESIGN

Data on patients who underwent endoscopic retrograde biliary drainage with covered or uncovered Wallstents for the palliation of unresectable distal malignant biliary obstruction were collected. Stent patency, complications, and causes of stent occlusion were analyzed.

SETTING

We collected the data retrospectively.

PATIENTS

A total of 77 patients received Wallstents for unresectable distal malignant biliary obstruction.

INTERVENTIONS

Endoscopic sphincterotomy was performed, and a Wallstent was deployed after guidewire passage. Polyurethane-covered Wallstents were used in 36 patients and uncovered Wallstents in 41 patients.

RESULTS

Stent migration occurred in 3 of the covered Wallstent group and in 1 of the uncovered Wallstent group. Cholecystitis occurred in 1 of the covered Wallstent group but in none of the uncovered Wallstent group. Stent occlusion occurred after a mean of 398 days in the covered group and after 319 days in the uncovered Wallstent group (P > .05). Stent patency rates were 83%, 78%, 67%, and 54% at 100, 200, 300, and 400 days, respectively, in covered group and 83%, 66%, 54%, and 36% in the uncovered group, which was not significantly different.

LIMITATIONS

This study is not a prospective randomized study and sample size is not large.

CONCLUSIONS

Covered Wallstents are safe with acceptable complication rates. However, we found no significant difference between the stent patencies of covered and uncovered Wallstents.

Covered versus uncovered wallstent for malignant extrahepatic biliary obstruction: a cohort comparative analysis

BACKGROUND & AIMS

We examined the use of both covered and uncovered Wallstents in patients with malignant extrahepatic biliary obstruction to determine whether use of covered Wallstents prolonged stent patency without increasing procedure-related complications.

METHODS

Commercially available silicone-covered Wallstents were prospectively evaluated in 98 patients who underwent insertion from December 2002-December 2004. Those data were compared with data obtained by retrospectively studying 108 consecutive patients who underwent endoscopic insertion of uncovered Wallstents between January 2000-November 2002, and for whom accurate and complete follow-up details were available.

RESULTS

The mean stent patency was similar for both groups, 148.9 days (range, 3-667 days) for covered Wallstents and 143.5 days (3-910 days) for uncovered Wallstents (P = .531). The 2 groups also did not significantly differ in terms of cumulative stent patency according to the Kaplan-Meier lifetime table. The incidence of mild pancreatitis was similar in both groups, occurring in 6 patients with covered stents (6/98, 6.1%) and 2 patients with uncovered stents (2/108, 1.9%) (P = .154). Excluding those patients who had previously undergone cholecystectomy, acute cholecystitis occurred in 5 of 88 patients with covered Wallstents (6.1%) and 1 of 100 patients with uncovered stents (1%) (P = .104). Stent migration occurred in 6 patients with covered stents (6.1%) and 0 patients with uncovered stents (P = .011).

CONCLUSION

Covered Wallstents might not prolong stent patency compared with uncovered Wallstents when used in the management of malignant extrahepatic biliary obstruction.

Palliative biliary stents for obstructing pancreatic carcinoma

BACKGROUND

Palliative endoscopic stents or surgical by-pass are often required for inoperable pancreatic carcinoma to relieve symptomatic obstruction of the distal biliary tree. The optimal method of intervention remains unknown.

OBJECTIVES

To compare surgery, metal endoscopic stents and plastic endoscopic stents in the relief of distal biliary obstruction in patients with inoperable pancreatic carcinoma.

SEARCH STRATEGY

We searched the databases of the Cochrane Upper Gastrointestinal and Pancreatic Group specialised register, Cochrane Central Register of Controlled Trials, MEDLINE, EMBASE, CancerLit, Current Concepts Database and BIDS (September 2002 to September 2004). The searches were re-run in December 2005 and we are awaiting further details on two trials. Reference lists of articles and published abstracts from UEGW and DDW were hand-searched.

SELECTION CRITERIA

Randomised controlled trials (RCTs) comparing surgery to endoscopic stenting, endoscopic metal stents to plastic stents, and different types of endoscopic plastic and metal stents, used to relieve obstruction of the distal bile duct in patients with inoperable pancreatic carcinoma.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed trial quality and extracted data. Adverse effects information was collected from the trials.

MAIN RESULTS

Twenty-one trials involving 1,454 people were included. Based on meta-analysis, endoscopic stenting with plastic stents appears to be associated with a reduced risk of complications (RR 0.60, 95% CI 0.45 - 0.81), but with higher risk of recurrent biliary obstruction prior to death (RR 18.59, 95% CI 5.33 - 64.86) when compared with surgery. There was a trend towards higher 30-day mortality in the surgical group (p=0.07, RR 0.58, 95% CI 0.32, 1.04). There was no evidence of a difference in technical or therapeutic success. Other outcomes were not suitable for meta-analysis. No trials comparing endoscopic metal stents to surgery were identified. In endoscopic stent comparisons, metal biliary stents appear to have a lower risk of recurrent biliary obstruction than plastic stents (RR 0.52, 95% CI 0.39 - 0.69). There was no significant statistical difference in technical success, therapeutic success, complications or 30-day mortality using meta-analysis. A narrative review of studies of the cost-effectiveness of metal stents drew conflicting conclusions, but results may be dependent on the patients' length of survival.Neither Teflon, hydrourethane, or hydrophilic coating appear to improve the patency of plastic stents above polyethylene in the trials reviewed. Only perflouro alkoxy plastic stents had superior outcome to polyethylene stents in one trial. The single eligible trial comparing types of metal stents reported higher patency with covered stents, but also a higher risk of complications. These results are based on review of the trials individual results only.

AUTHORS' CONCLUSIONS

Endoscopic metal stents are the intervention of choice at present in patients with malignant distal obstructive jaundice due to pancreatic carcinoma. In patients with short predicted survival, their patency benefits over plastic stents may not be realised. Further RCTs are needed to determine the optimal stent type for these patients.

Endoscopic removal of malfunctioning biliary self-expandable metallic stents

BACKGROUND

Endoscopic removal of malfunctioning self-expandable metallic biliary stents (SEMS) is difficult and not well described. The aim of this study is to review the indications, the techniques, and the results of SEMS removal in a cohort of patients with malfunctioning stents.

METHODS

All patients who underwent an attempt at endoscopic removal of biliary SEMS over a 5-year period were retrospectively identified. The main indications for SEMS removal were the following: distal migration of the stent or impaction to the duodenum, impaction into the bile-duct wall, tissue ingrowth, and inappropriate length of the stent causing occlusion of intrahepatic ducts. SEMS were removed by using foreign-body forceps or polypectomy snares.

RESULTS

Endoscopic removal of 39 SEMS (13 uncovered and 26 covered) was attempted in 29 patients (17 men; mean age, 66 years). SEMS extraction was attempted after a mean of 7.5 months (8.75 months standard deviation) post-SEMS insertion. Removal was successful in 20 patients (68.9%) and in 29 SEMS (74.3%). Covered SEMS were effectively removed more frequently than uncovered ones: 24 of 26 (92.3%) and 5 of 13 (38.4%), respectively (p < 0.05). No major complications were recorded. Multivariate analysis showed that the time interval between insertion and removal, SEMS length, stent-mesh design (zigzag vs. interlaced), and indication for removal were not predictive of success at stent removal.

CONCLUSIONS

Endoscopic removal of biliary SEMS is feasible and safe in more than 70% of cases. Because only 38% of uncovered SEMS were removable, the presence of a stent covering is the only factor predictive of successful stent extraction. The presence of diffuse and severe ingrowth was the main feature limiting SEMS removal.

Efficacy and safety of the covered Wallstent in patients with distal malignant biliary obstruction

BACKGROUND

The aim of this study was to evaluate the efficacy and the safety of the covered Wallstent, a commercially available silicone-covered, self-expandable metallic stent (covered Wallstent), for the treatment of distal malignant biliary obstruction.

METHODS

Sixty-nine consecutive patients with unresectable distal malignant biliary obstruction who underwent covered Wallstent placement between October 2001 and October 2003 were studied at 4 affiliated hospitals.

RESULTS

Mean stent patency and mean survival were 139.1 days and 200.9 days, respectively. Stent occlusion occurred in 7 cases (10.1%), but tumor ingrowth was not observed. Seventeen complications, including 5 cholangitis (7.2%), 4 stent migration (5.8%), 4 cholecystitis (5.8%), and 4 pancreatitis (5.8%) were observed in 16 patients (23.2%). Stent misplacement was observed in 7 patients (10.1%).

CONCLUSIONS

Covered Wallstent is effective in preventing tumor ingrowth for the treatment of distal malignant biliary obstruction. However, the overall complication rate may be higher than uncovered self-expanding metal stents and covered self-expanding metal stents of different design.

Effects of a holmium-166 incorporated covered stent placement in normal canine common bile ducts

PURPOSE

A specially designed self-expandable covered metallic stent incorporated with beta-emitting radioisotope, Holmium-166 (Ho-166), was developed for delivering intraluminal brachytherapy as well as for internal bile drainage in malignant biliary stricture. The purpose of the study was to demonstrate the safety and tissue response of the radioactive metallic stent on the normal canine common bile duct (CBD) prior to the clinical application.

MATERIALS AND METHODS

Nitinol self-expandable stents (diameter; 4 mm, length; 20 mm) were covered with polyurethane membrane (50 microm thick) containing 21 to 135 muCi of Ho-166 (mean, 77.9 microCi). To prevent migration of stent, the membrane covered only the middle 1 cm of the stent and the ends of the stent were left uncovered. The stents were placed in the CBD of 20 healthy beagle dogs. For control, non-radioactive covered stents were placed in another three dogs. The dogs were killed 3 to 6 months after stent insertion and histopathologic examination of CBD was performed.

RESULTS

There was no stent migration in all cases. Varying degrees of papillary mucosal hyperplasia leading to significant narrowing of the lumen was observed within the lumen of the bare portion and under the mucosal surface of the non-radioactive covered stents. However, fibrosis was noted in Ho-166 coated area, instead of mucosal hyperplasia. Severity of fibrosis was correlated with estimated radiation dose. Despite high dose, there was no perforation of CBD wall. The membrane of Ho-166 coat was disrupted in some cases of 6 months follow-up.

CONCLUSIONS

Holmium-166 incorporated covered stents demonstrated fibrosis of CBD wall and inhibition of ingrowth of mucosal hyperplasia without serious complication such as perforation, while control group showed severe mucosal hyperplasia.

Endoscopic palliation of pancreaticobiliary malignancies

The palliation of pancreaticobiliary malignancies has changed over the last two decades. With the development of biliary stents, minimally invasive procedures have replaced surgical techniques. Endoscopically placed stents remain the mainstay for the palliative treatment of malignant biliary obstruction from unresectable pancreaticobiliary tumors. Further improvements in stent designs and advances in other endoscopic technologies are expected, and these should expand the role of minimally invasive palliation. This article reviews the current and anticipated roles of endoscopic techniques in the palliation of pancreaticobiliary malignancies.

Endobiliary stents for palliation in patients with malignant obstructive jaundice

BACKGROUND

Endobiliary drainage for malignant obstructive jaundice presents a viable palliative alternative. Its role and efficacy depend on factors related to the stent, procedure, and patient.

GOALS

To review the evidence in the literature in which settings plastic or metal stents are cost-effective, and whether adjuvant measures or patient-related factors affect duration of stent patency.

STUDY

Using databases a literature search was performed for papers published from 1979 to April 2004. All retrieved papers reporting experimental or clinical observations were rated according to strength of evidence, and carefully analyzed.

RESULTS AND CONCLUSIONS

Metal stents (Wallstent) stay patent longer than plastic stents (large-bore polyethylene with side-holes), overall median 250 and 110 days, respectively, and seem cost-effective in patients with longer than about 6 months survival, which cannot be accurately predicted. Antibiotics or choleretic agents do not prolong stent patency in clinical settings. In case of stent occlusion, indicated stent exchanges and insertion of a plastic stent, respectively, seem cost-effective in patients initially treated with plastic and metal stents.

Efficacy and complications of covered Wallstents in malignant distal biliary obstruction

BACKGROUND

This study evaluated the efficacy and the complications associated with the use of the covered Wallstent in the setting of unresectable malignant biliary obstruction.

METHODS

Between March 2001 and January 2003, all patients with distal malignant biliary obstruction that required drainage were treated with a covered Wallstent. Every 2 months, the patients were evaluated clinically and biochemical tests of liver function were obtained. Data were recorded for the following variables: early complications (within 30 days of stent placement), early and late stent occlusion, duration of stent patency, need for subsequent biliary intervention, and patient survival.

RESULTS

A total of 88 covered Wallstents were inserted in 80 patients. Stent patency rates at 3, 6, and 12 months were 90%, 82%, and 78%, respectively. Complications included stent migration (5), stent occlusion (12), episodes of cholecystitis (3), and episodes of post-ERCP pancreatitis (5). Biliary intervention was required in 9 patients subsequent to placement of the initial covered Wallstent.

CONCLUSIONS

Deployment of a covered Wallstent is safe and relatively easy. It achieves biliary drainage with an acceptable risk to benefit ratio in the majority of patients with distal malignant biliary obstruction.

N/A

N/A

Open-biopsy-forceps technique for endoscopic removal of distally migrated and impacted biliary metallic stents

BACKGROUND

Endoscopic removal of distally migrated and impacted biliary metallic stents is technically challenging. An open-biopsy-forceps technique for endoscopic removal of these migrated stents is described.

METHODS

The technique was used in 4 patients with distally migrated and impacted covered metallic stents. A closed biopsy forceps was advanced through the stent mesh and opened within the stent to form an "anchor." With endoscope withdrawal, the stent was dislodged easily from the duodenum to the stomach. After grasping an end of the stent with a snare, the stent was removed by complete withdrawal of the endoscope.

OBSERVATIONS

In all patients, the impacted stent was removed successfully. Mean time for removal was 10.2 minutes. Although ulceration was evident in the duodenal wall where the distal stent end was impacted in all patients, no other complication or adverse event was observed.

CONCLUSIONS

The open-biopsy-forceps technique is useful for endoscopic removal of distally migrated and impacted biliary metallic stents.

Biliary and pancreatic stents

The use of biliary and pancreatic stents has increased significantly during the last 2 decades because of improvements in available endoscopes and endoscopic accessories, as well as better techniques. The number of endoscopists who can successfully complete these demanding procedures has also increased, as have the indications for stent therapy in biliary and pancreatic diseases. Stents are now made in various shapes and configurations from different types of polymers (plastics), various expandable metallic alloys, and bioabsorbable materials. Most of the available data relate to plastic and metallic stents for biliary tract disease; the data for pancreatic disease are fewer and involve a smaller number of patients. This article reviews the most recent available data concerning biliary and pancreatic stents and discusses possible future developments. It does not attempt to cover all data reported in biliopancreatic stent therapy.

Multicenter randomized trial of the spiral Z-stent compared with the Wallstent for malignant biliary obstruction

BACKGROUND

The industry standard since 1990 for self-expanding biliary metallic stents has been the Wallstent. In 1998 the Spiral Z-stent was released. This randomized trial compared the Z-stent with the Wallstent in the treatment of malignant biliary obstruction.

METHODS

Patients with unresectable malignant biliary obstruction distal to the bile duct bifurcation were randomized to receive a 10-mm diameter Wallstent or a 10-mm diameter Z-stent.

RESULTS

A total of 145 patients were randomized; 13 were excluded. Sixty-four patients who received a Z-stent and 68 who had a Wallstent are included in the analysis. Tumors responsible for bile duct obstruction were pancreatic cancer (108), cholangiocarcinoma (15), metastatic cancer (6), and papillary cancer (3). Metallic stents were successfully placed in all patients. Seven technical problems were encountered during placement of the Z-stent and 5 with the Wallstent. There were 21 occlusions requiring reintervention (8 Z-stent, 13 Wallstent; p = 0.30). Median time to reintervention was the following: Z-stent, 162 days; Wallstent, 150 days (p = 0.22). A total of 104 patients died of progressive disease or other cause; 7 patients remain alive with patent stents. The overall calculated median patency rates were: Z-stent, 152 days; Wallstent, 154 days (p = 0.90).

CONCLUSIONS

The Spiral Z-stent is comparable with the Wallstent in terms of placement, occlusion rates, and overall patency. Occasional early occlusion of both stents suggests tumor characteristics instead of the size of the mesh openings in the stents as important factors.

Biliary endoscopy

Highlighting this year was the National Institutes of Health (NIH) State-of-the-Science Conference on endoscopic retrograde cholangiopancreatography. The panel addressed controversies in biliary endoscopy and set the framework for future funding for clinical research endeavors. With respect to biliary endoscopy, the literature addressed therapy for malignant biliary obstruction, choledocholithiasis, and biliary complications post-liver transplant.