Efficacy and complications of covered Wallstents in malignant distal biliary obstruction

Otaru consensus on biliary stenting for unresectable distal malignant biliary obstruction

Endoscopic biliary drainage with biliary stent placement is the treatment of choice for palliation in patients with malignant biliary obstruction caused by unresectable neoplasms. Various biliary stent designs have become available, but lack of a clear consensus persists on the use of covered versus uncovered metal stents in malignant distal bile duct obstructions, and plastic versus metal stents. In 2012, the European Society of Gastrointestinal Endoscopy indicated guidelines for biliary stenting. Accordingly, the consensus meeting for biliary stenting was held at the Endoscopic Forum Japan 2012, and four selected statements related to stent placement for distal malignant biliary obstruction were discussed to produce a consensus. Two of four statements (related to the usefulness of self-expandable metallic stents, and reintervention after stenting) were agreed upon by almost all participants. Nevertheless, our opinions were divided on the other two statements (necessity of sphincterotomy for stenting, and covered metal stent versus uncovered metal stent). We herein report the results of the meeting, and present proposed new statements via discussion.

Necessity for endoscopic sphincterotomy for biliary stenting in cases of malignant biliary obstruction

Endoscopic biliary stenting is a useful way to treat distal malignant biliary strictures that are not eligible for surgery. A 10-Fr plastic or metal stent is used for stenting. Typically, endoscopic sphincterotomy (EST) has often been carried out as a way to prevent pancreatitis after stent placement given the ease of stent insertion, but EST has flaws such as bleeding and stent migration.The present study describes the need for EST prior to stent placement.

Lethal post-endoscopic retrograde cholangiopancreatography pancreatitis following fully covered metal stent placement in distal biliary obstruction due to unresectable cholangiocarcinoma

Biliary self-expandable metallic stent (SEMS) is the preferred and first-line therapy for unresectable malignant biliary obstruction. To date, several reports have revealed the relatively high incidence of acute complications such as pancreatitis and cholecystitis due to mechanical stent compression. In the present case, we encountered fatal pancreatitis following fully covered metal stent placement. An 85-year-old man had middle bile duct strictures due to cholangiocarcinoma. A 10-mm diameter fully covered SEMS was placed across the papilla for biliary decompression. Laboratory data and physical evidence the following day revealed acute pancreatitis. Therefore, antibiotics and protein degeneration enzyme inhibitors were given. However, his condition did not improve. Two days after the procedure, we removed the stent and returned him to his original hospital. Serum amylase level decreased below 400 mg/dL 6 h after the procedure. However, the acute pancreatitis worsened. Although we treated the patient in the intensive care unit, he died 32 days after the second admission.

Biliary self-expandable metallic stent for unresectable malignant distal biliary obstruction: which is better: covered or uncovered?

Self-expandable metallic stents (SEMS) are a widely accepted biliary endoprosthesis for patients with unresectable malignant distal biliary obstruction. There are two types of SEMS: covered and uncovered. Uncovered SEMS (UCSEMS) embed into the biliary wall due to their mesh structure and self-expandability, and are resistant to migration. However, the disadvantage of UCSEMS is occlusion due to tumor ingrowth (TI) via the stent mesh, and TI is the main cause of UCSEMS occlusion. To overcome this, covered SEMS (CSEMS) were developed and showed longer patency than UCSEMS. However, migration due to the non-embedded stent body is the main cause of CSEMS dysfunction. There are some randomized studies comparing CSEMS and UCSEMS; however, the results are different according to each study. From one meta-analysis, CSEMS showed longer patency than UCSEMS. A literature review revealed that covered SEMS showed longer patency than UCSEMS. Some studies cannot clearly demonstrate the superiority of CSEMS, as the CSEMS used did not prevent TI or migration. Mechanical properties of SEMS may influence the occurrence of complications. A recent clinical study comparing the Covered Wallstent and the Covered WallFlex revealed superiority of the WallFlex for the prevention of migration. Reducing the axial force and increasing the radial force may lead to good results. Migration of CSEMS should be prevented by taking into consideration the mechanical properties of stents and development of anti-migration systems.

Safety and efficacy of radiofrequency ablation in the management of unresectable bile duct and pancreatic cancer: a novel palliation technique

Objectives. Radiofrequency ablation (RFA) has replaced photodynamic therapy for premalignant and malignant lesions of the esophagus. However, there is limited experience in the bile duct. The objective of this pilot study was to assess the safety and efficacy of RFA in malignant biliary strictures.

METHODS

Twenty patients with unresectable malignant biliary strictures underwent RFA with stenting between June 2010 and July 2012. Diameters of the stricture before and after RFA, immediate and 30 day complications and stent patency were recorded prospectively. Results. A total of 25 strictures were treated. Mean stricture length treated was 15.2 mm (SD = 8.7 mm, Range = 3.5-33 mm). Mean stricture diameter before RFA was 1.7 mm (SD = 0.9 mm, Range = 0.5-3.4 mm) while the mean diameter after RFA was 5.2 mm (SD = 2 mm, Range = 2.6-9 mm). There was a significant increase of 3.5 mm (t = 10.8, DF = 24, P value = <.0001) in the bile duct diameter post RFA. Five patients presented with pain after the procedure, but only one developed mild post-ERCP pancreatitis and cholecystitis.

CONCLUSIONS

Radiofrequency ablation can be a safe palliation option for unresectable malignant biliary strictures. A multicenter randomized controlled trial is required to confirm the long term benefits of RFA and stenting compared to stenting alone.

Prospective evaluation of the partially covered nitinol "ComVi" stent for malignant non hilar biliary obstruction

BACKGROUND

Biliary partially covered self-expandable metal stents (PC-SEMS) offer prolonged relief of symptoms of biliary obstruction but may induce complications including pancreatitis, cholecystitis and migration.

AIMS

To assess efficacy and safety of the ComVi partially covered self-expandable metal stents as primary palliative treatment of distal malignant biliary obstruction.

METHODS

Seventy patients (mean age 69.2 years) with distal malignant biliary strictures were prospectively included and underwent endoscopic retrograde cholangio-pancreatography and partially covered self-expandable metal stents placement. Follow-up was done for 12 months. self-expandable metal stents patency, survival and complication-rate after partially covered self-expandable metal stents placement were evaluated.

RESULTS

Overall median survival time was 190 days (30-856). Forty-four patients (62.8%) died after median 175.5 days (30-614) without signs of stent dysfunction; 37 patients (52.8%) were alive after 6 months without signs of self-expandable metal stents occlusion. Survival rapidly dropped between 8 and 12 months after treatment. Survival was not influenced by sex (P = 0.1) or type of neoplasia (P = 0.178). Median survival was longer (254 days [44-836]) in patients who underwent chemotherapy (P < 0.0001). Partially covered self-expandable metal stents occlusion had 24 (35.7%) patients 154 days (35-485) after treatment. Median survival after re-treatment was 66 days (13-597). Cholecystitis occurred in one patient (1.7%).

CONCLUSIONS

The ComVi partially covered self-expandable metal stents is effective for palliation of biliary obstruction secondary to distal malignant biliary strictures. Self-expandable metal stents patency during follow-up is satisfactory without significant complications.

Endoscopic management of malignant bile duct strictures

Malignant biliary obstruction can arise from intrahepatic, extrahepatic, and hilar locations from either primary or metastatic disease. Biliary-enteric surgical bypass has been surpassed in the last 20 years by endoscopic balloon dilation and stenting. The goal of stenting for biliary decompression is to palliate obstructive symptoms; it has not been shown that survival is affected by stenting alone. Novel endoscopic therapies, including photodynamic therapy and radiofrequency ablation, have been evaluated and show promise. Both therapies seem to be safe and effective in the treatment of malignant bile duct strictures but are in need of prospective studies of longer duration.

Covered and uncovered self-expandable metallic Hanarostents are equally efficacious in the drainage of extrahepatic malignant strictures. Results of a double-blind randomized study

BACKGROUND

Self-expandable metallic stents (SEMS) placement is a standard treatment for inoperable malignant bile duct strictures. Covered SEMS have been introduced to avoid stent occlusion by tumor ingrowth. The aims were to compare covered and uncovered stents in terms of patency, efficacy and complication rate.

MATERIAL AND METHODS

Consecutive patients with inoperable malignant distal biliary strictures were included in the study and randomized to receive a covered (n = 34) or uncovered (n = 34) Hanaro SEMS. Follow-up was performed by nurses after 18 h, 48 h, 2 weeks and thereafter every month until stent dysfunction or the patient died. Outcomes were measured as follows: the patients reported urine and stool color, presence of fever and abdominal pain. Liver function tests and CRP were analyzed each time. The procedure time and complications were monitored. The follow-up was blinded to stent type.

RESULTS

The median patient age was 79 years (IQR: 66-83, R: 54-92), 59% were female and 85% had the gallbladder in situ. There was no difference between covered and uncovered stents in terms of procedure time (median: 30 min (20-38, R: 12-90) vs. 30 min (IQR: 20-42, R: 12-70)), stent patency (median: 153 days (IQR: 65-217; R: 20-609) vs. median of 127 days (IQR: 70-196; R: 18-486)) or patient survival (median: 154 days (IQR: 65-217; R: 21-609) vs 157 days (IQR: 70-273, R: 20-690)). Eighty-seven percent died with a patent covered and 83% with an uncovered stent (n.s.). Two early complications occurred (sepsis; pancreatitis), both with covered stents.

CONCLUSION

There is no clinical difference between covered and uncovered biliary Hanaro SEMS. Both types are easily inserted with low complication rate and have long-term patency.

A multicenter, prospective study of a new fully covered expandable metal biliary stent for the palliative treatment of malignant bile duct obstruction

Background and Study Aims. Endoscopic placement of self-expanding metal stents (SEMSs) is indicated for palliation of inoperable malignant biliary obstruction. A fully covered biliary SEMS (WallFlex Biliary RX Boston Scientific, Natick, USA) was assessed for palliation of extrahepatic malignant biliary obstruction. Patients and Methods. 58 patients were included in this prospective, multicenter series conducted under an FDA-approved IDE. Main outcome measurements included (1) absence of stent occlusion within six months or until death, whichever occurred first and (2) technical success, need for reintervention, bilirubin levels, stent patency, time to stent occlusion, and adverse events. Results. Technical success was achieved in 98% (57/58), with demonstrated acute removability in two patients. Adequate clinical palliation until completion of followup was achievedin 98% (54/55) of evaluable patients, with 1 reintervention due to stent obstruction after 142 days. Mean total bilirubin decreased from 8.9 mg/dL to 1.2 mg/dL at 1 month. Device-related adverse events were limited and included 2 cases of cholecystitis. One stent migrated following radiation therapy. Conclusions. The WallFlex Biliary fully covered stent yielded technically successful placement with uncomplicated acute removal where required, appropriate reduction in bilirubin levels, and low rates of stent migration and occlusion. This SEMS allows successful palliation of malignant extrahepatic biliary obstruction.

Endoscopic management of chronic pancreatitis

Chronic pancreatitis (CP) is a common gastrointestinal illness, which affects the quality of life with substantial morbidity and mortality. The management includes medical, endoscopic and surgical approaches with the need for interaction between various specialties, calling for a concerted multidisciplinary approach. However, at the time of this publication, guidelines to establish care of these patients are lacking. This review provides the reader with a comprehensive overview of the studies summarizing the various treatment options available, including medical, surgical and endoscopic options. In addition, technological advances such as endoscopic retrograde cholangiopancreatogrophy, endoscopic shock wave lithotripsy and endoscopic ultrasound can now be offered with reasonable success for pancreatic decompression, stricture dilatation with stent placement, stone fragmentation, pseudocyst drainage, and other endoscopic interventions such as celiac plexus block for pain relief. We emphasize the endoscopic options in this review, and attempt to extract the most up to date information from the current literature. The treatment of CP and its complications are discussed extensively. Complications such as biliary strictures. pancreatic pseudocysts, and chronic pain are common issues that arise as long-term complications of CP. These often require endoscopic or surgical management and possibly a combination of approaches, however choosing amongst the various therapeutic and palliative modalities while weighing the risks and benefits, makes the management of CP challenging. Treatment goals should be not just to control symptoms but also to prevent disease progression. Our aim in this paper is to advocate and emphasize an evidence based approach for the management of CP and associated long term complications.

Classification, diagnosis, and management of cholangiocarcinoma

Cholangiocarcinomas (CCAs) are tumors that develop along the biliary tract. Depending on their site of origin, they have different features and require specific treatments. Classification of CCAs into intrahepatic, perihilar, and distal subgroups has helped standardize the registration, treatment, and study of this lethal malignancy. Physicians should remain aware that cirrhosis and viral hepatitis B and C are predisposing conditions for intrahepatic CCA. Treatment options under development include locoregional therapies and a chemotherapy regimen of gemcitabine and cisplatin. It is a challenge to diagnose perihilar CCA, but an advanced cytologic technique of fluorescence in situ hybridization for polysomy can aid in diagnosis. It is important to increase our understanding of the use of biliary stents and liver transplantation in the management of perihilar CCA, as well as to distinguish distal CCAs from pancreatic cancer, because of different outcomes from surgery. We review advances in the classification, diagnosis, and staging of CCA, along with treatment options.

Mucosal hyperplasia in an uncovered portion of partially covered metal stent

Covered self-expandable metal stents were developed to overcome tumor in-growth through the metal mesh. Stent migration is one of their malfunctions. Recently, the partially covered wallflex stent (PCWS) was developed with flared ends to prevent migration However, difficulty has been reported in its removal. We describe the removal of a PCWS embedded in mucosal hyperplasia at the uncovered proximal flared end, visualized by using SpyGlass cholangioscopy.

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.

Comparison of partially covered nitinol stents with partially covered stainless stents as a historical control in a multicenter study of distal malignant biliary obstruction: the WATCH study

BACKGROUND

Covered self-expandable metal stents (CSEMSs) were developed to prevent tumor ingrowth, but stent migration is one of the problems with CSEMSs.

OBJECTIVE

To evaluate a new, commercially available CSEMS with flared ends and low axial force compared with a commercially available CSEMS without the anti-migration system and high axial force.

DESIGN

Multicenter, prospective study with a historical cohort.

SETTING

Twenty Japanese referral centers.

PATIENTS

This study involved patients with unresectable distal malignant biliary obstruction.

INTERVENTION

Placement of a new, commercially available, partially covered SEMS.

MAIN OUTCOME MEASUREMENTS

Recurrent biliary obstruction rate, time to recurrent biliary obstruction, stent-related complications, survival.

RESULTS

Between April 2009 and March 2010, 141 patients underwent partially covered nitinol stent placement, and between May 2001 and January 2007, 138 patients underwent placement of partially covered stainless stents as a historical control. The silicone cover of the partially covered nitinol stents prevented tumor ingrowth. There were no significant differences in survival (229 vs 219 days; P = .250) or the rate of recurrent biliary obstruction (33% vs 38%; P = .385) between partially covered nitinol stents and partially covered stainless stents. Stent migration was less frequent (8% vs 17%; P = .019), and time to recurrent biliary obstruction was significantly longer (373 vs 285 days; P = .007) with partially covered nitinol stents. Stent removal was successful in 26 of 27 patients (96%).

LIMITATIONS

Nonrandomized, controlled trial.

CONCLUSION

Partially covered nitinol stents with an anti-migration system and less axial force demonstrated longer time to recurrent biliary obstruction with no tumor ingrowth and less stent migration.

Endoscopic ultrasound-guided biliary drainage with placement of a fully covered metal stent for malignant biliary obstruction

AIM: To determine the utility of endoscopic ultrasound-guided biliary drainage (EUS-BD) with a fully covered self-expandable metal stent for managing malignant biliary stricture.

METHODS: We collected data from 13 patients who presented with malignant biliary obstruction and underwent EUS-BD with a nitinol fully covered self-expandable metal stent when endoscopic retrograde cholangiopancreatography (ERCP) fails. EUS-guided choledochoduodenostomy (EUS-CD) and EUS-guided hepaticogastrostomy (EUS-HG) was performed in 9 patients and 4 patients, respectively.

RESULTS: The technical and functional success rate was 92.3% (12/13) and 91.7% (11/12), respectively. Using an intrahepatic approach (EUS-HG, n = 4), there was mild peritonitis (n = 1) and migration of the metal stent to the stomach (n = 1). With an extrahepatic approach (EUS-CD, n = 10), there was pneumoperitoneum (n = 2), migration (n = 2), and mild peritonitis (n = 1). All patients were managed conservatively with antibiotics. During follow-up (range, 1-12 mo), there was re-intervention (4/13 cases, 30.7%) necessitated by stent migration (n = 2) and stent occlusion (n = 2).

CONCLUSION: EUS-BD with a nitinol fully covered self-expandable metal stent may be a feasible and effective treatment option in patients with malignant biliary obstruction when ERCP fails.

Clinical benefit of radiation therapy and metallic stenting for unresectable hilar cholangiocarcinoma

AIM: To determine the efficacy of external beam radiotherapy (EBRT), with or without intraluminal brachytherapy (ILBT), in patients with non-resected locally advanced hilar cholangiocarcinoma.

METHODS: We analyzed 64 patients with locally advanced hilar cholangiocarcinoma, including 25 who underwent resection (17 curative and 8 non-curative), 28 treated with radiotherapy, and 11 who received best supportive care (BSC). The radiotherapy group received EBRT (50 Gy, 30 fractions), with 11 receiving an additional 24 Gy (4 fractions) ILBT by iridium-192 with remote after loading. ILBT was performed using percutaneous transhepatic biliary drainage (PTBD) route. Uncovered metallic stents (UMS) were inserted into non-resected patients with obstructive jaundice, with the exception of four patients who received percutaneous transhepatic biliary drainage only. UMS were placed endoscopically or percutaneously, depending on the initial drainage procedure. The primary endpoints were patient death or stent occlusion. Survival time of patients in the radiotherapy group was compared with that of patients in the resection and BSC groups. Stent patency was compared in the radiotherapy and BSC groups.

RESULTS: No statistically significant differences in patient characteristics were found among the resection, radiotherapy, and BSC groups. Three patients in the radiotherapy group and one in the BSC group did not receive UMS insertion but received PTBD alone; cholangitis occurred after endoscopic stenting, and patients were treated with PTBD. A total of 16 patients were administered additional systemic chemotherapy (5-fluorouracil-based regimen in 9, S-1 in 6, and gemcitabine in 1). Overall survival varied significantly among groups, with median survival times of 48.7 mo in the surgery group, 22.1 mo in the radiotherapy group, and 5.7 mo in the BSC group. Patients who underwent curative resection survived significantly longer than those who were not candidates for surgery (P = 0.0076). Cumulative survival in the radiotherapy group was significantly longer than in the BSC group (P = 0.0031), but did not differ significantly from those in the non-resection group. Furthermore, the median survival time of patients in the radiotherapy group who were considered for possible resection (excluding the seven patients who were not candidates for surgery due to comorbid disease or age) was 25.9 mo. Stent patency was evaluated only in the 24 patients who received a metallic stent. Stent patency was significantly longer in the radiotherapy than in the BSC group (P = 0.0165). Biliary drainage was not eliminated in any patient. To determine the efficacy of ILBT, we compared survival time and stent patency in the EBRT alone and EBRT plus ILBT groups. However, we found no significant difference in survival time between groups or for stent patencies. Hemorrhagic gastroduodenal ulcers were observed in 5 patients (17.9%), three in the EBRT plus ILBT group and two in the EBRT alone group. Ulcers occurred 5 mo, 7 mo, 8 mo, 16 mo, and 29 mo following radiotherapy. All patients required hospitalization, but blood transfusions were unnecessary. All 5 patients recovered following the administration of anti-ulcer medication.

CONCLUSION: Radiotherapy improved patient prognosis and the patency of uncovered metallic stents in patients with locally advanced hilar cholangiocarcinoma, but ILBT provided no additional benefits.

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.

Endoscopic palliation of pancreatic cancer

There is no doubt that our long-range goal is to cure pancreatic cancer. Realistically, most of what we can do currently is treat the disabling symptoms of this dreadful disease. Biliary decompression, intestinal stenting, celiac plexus neurolysis, and fiducial placement are some of the endoscopic procedures that aim to provide better quality of life to patients suffering from this disease. A thorough understanding of these options will help patients make good decisions in choosing the proper treatment. Endoscopists who perform these procedures must possess great skills, but importantly, they must also be compassionate and act with good judgment.

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.

Endoscopic stent placement in the palliation of malignant biliary obstruction

Biliary drainage with biliary stent placement is the treatment of choice for palliation in patients with malignant biliary obstruction caused by unresectable neoplasms. In such patients, the endoscopic approach can be initially used with percutaneous radiological intervention. In patients with unresectable malignant distal bile duct obstructions, endoscopic biliary drainage with biliary stent placement has now become the main and least invasive palliative modality, which has been proven to be more effective in >80% of cases with lower morbidity than surgery, and perhaps may provide a survival benefit. In patients with unresectable malignant hilar obstruction, the endoscopic approach for biliary drainage with biliary stent placement has also been considered as the treatment of choice. There is still a lack of clear consensus on the use of covered versus uncovered metal stents in malignant distal bile duct obstructions and plastic versus metal stents and unilateral versus bilateral drainage in malignant hilar obstructions.

Biliary stents in the millennium

Biliary stents have now been in use for over two decades. Although a plethora of literature has been published on them, this review article is unique in its attempt to summarize important landmark trials and their implications on the management of various pancreatico-biliary disorders. This article will cover the various types of stents currently being used, established and upcoming indications, techniques of placement, and complications associated with stent use.

Risk factors for pancreatitis following transpapillary self-expandable metal stent placement

BACKGROUND

Pancreatitis is one of complications after self-expandable metal stent (SEMS) placement. The purpose of this study was to evaluate risk factors for pancreatitis after endoscopic SEMS placement for malignant biliary obstruction (MBO).

METHODS

We retrospectively reviewed 370 consecutive patients who underwent initial transpapillary SEMS placement for biliary decompression. The characteristics of inserted SEMSs were classified according to axial and radial force.

RESULTS

Pancreatitis following SEMS insertion was observed in 22 patients (6%). All of them were mild according to consensus criteria. Univariate analysis indicated that injections of contrast into the pancreatic duct (frequency of pancreatitis, 10.3%), the placement of an SEMS with high axial force (8.3%), and nonpancreatic cancer (16.1%) significantly contributed to the development of pancreatitis, whereas female gender, a younger age, a covered SEMS, and a SEMS with high radial force or without a biliary sphincterotomy did not. In a multivariate risk model, SEMSs with high axial force (odds ratio [OR], 3.69; p = 0.022) and nonpancreatic cancer (OR, 5.52; p < 0.001) were significant risk factors for pancreatitis.

CONCLUSIONS

SEMSs with high axial force and an etiology of MBO other than pancreatic cancer were strongly associated with a high incidence of pancreatitis following transpapillary SEMS placement in patients with distal MBO.

Results of a Japanese multicenter, randomized trial of endoscopic stenting for non-resectable pancreatic head cancer (JM-test): Covered Wallstent versus DoubleLayer stent

BACKGROUND

No study has compared covered metallic stents with Tannenbaum stents. We evaluated the efficacy of the DoubleLayer stent (DLS) and Covered Wallstent (CWS) in patients with pancreatic head cancer (PHC).

PATIENTS & METHODS

This was a multicenter, prospective randomized study. Between October 2005 and December 2007, we enrolled 113 patients (58 DLS, 55 CWS) with unresectable PHC with distal biliary obstructions and observed them for at least 6 months.

RESULTS

No significant difference in patient survival was found between groups, with a median survival of 231 and 248 days in the DLS and CWS groups, respectively. The cumulative stent patency was significantly higher (P = 0.0072) in the CWS group. The respective mean and median stent patency was 202 and 133 days in the DLS group and 285 and 419 days in the CWS group. The incidence of DLS occlusion (53.5%) was significantly higher than that of CWS (23.6%; P = 0.0019). The respective causes of occlusion were tumor overgrowth (0, 1), ingrowth (0, 2), sludge (24, 2), food impaction (3, 5), kinking bile duct (2, 0), and other (2, 3). Other complications were cholecystitis (0, 4), pancreatitis (0, 1), migration (1, 5), liver abscess (2, 0), and other (1, 2). No significant difference in the incidence of complications between groups was observed.

CONCLUSION

CWS had significantly longer patency than DLS for the management of PHC with obstructive jaundice. The incidence of complications other than stent occlusion was higher in CWS, but this difference did not reach significance.

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.

Endoscopic palliation for pancreatic cancer

Pancreatic cancer is devastating due to its poor prognosis. Patients require a multidisciplinary approach to guide available options, mostly palliative because of advanced disease at presentation. Palliation including relief of biliary obstruction, gastric outlet obstruction, and cancer-related pain has become the focus in patients whose cancer is determined to be unresectable. Endoscopic stenting for biliary obstruction is an option for drainage to avoid the complications including jaundice, pruritus, infection, liver dysfunction and eventually failure. Enteral stents can relieve gastric obstruction and allow patients to resume oral intake. Pain is difficult to treat in cancer patients and endoscopic procedures such as pancreatic stenting and celiac plexus neurolysis can provide relief. The objective of endoscopic palliation is to primarily address symptoms as well improve quality of life.

Endoscopic biliary sphincterotomy is not required for transpapillary SEMS placement for biliary obstruction

BACKGROUND

Endoscopic retrograde cholangiopancreatography with biliary self-expanding metal stent placement is the preferred method of providing biliary drainage for pancreaticobiliary malignancies. Some endoscopists routinely perform biliary sphincterotomy to facilitate biliary stent placement and potentially minimize pancreatitis with transpapillary self-expanding metal stent placement.

AIMS

Our hypothesis was that biliary sphincterotomy has no effect on the success rate of transpapillary self-expanding metal stent placement and increases procedure-related complications.

METHODS

In a retrospective analysis, outcomes of two groups were compared: (1) self-expanding metal stent placement without biliary sphincterotomy, (2) self-expanding metal stent placement with biliary sphincterotomy during the same procedure. Complications and stent patency rates were evaluated.

RESULTS

There were 104 subjects included in the study. Post-sphincterotomy bleeding (p = 0.001) was associated with biliary sphincterotomy performed immediately prior to self-expanding metal stent placement. Importantly, self-expanding metal stent placement without biliary sphincterotomy was always technically successful and self-expanding metal stent placement without biliary sphincterotomy was not associated with pancreatitis.

CONCLUSIONS

Patients who undergo biliary sphincterotomy during transpapillary self-expanding metal stent placement experience more immediate complications than those who do not. Biliary sphincterotomy was not associated with longer stent patency. Self-expanding metal stent placement without a biliary sphincterotomy was not associated with pancreatitis regardless of the type of self-expanding metal stent used (covered or uncovered). Of the patients without a biliary sphincterotomy, 100% had successful stent placement, further arguing against its use in this setting.

New method of covered wallstents for distal malignant biliary obstruction to reduce early stent-related complications based on characteristics

AIM

We previously reported a low occlusion rate with covered Wallstents for malignant biliary obstruction, but stent-related complications other than occlusion posed a problem. A modified covered Wallstent insertion method based on stent characteristics was evaluated to reduce stent-related complications.

METHODS

A total of 138 patients with distal malignant biliary obstruction received covered Wallstent placement. From October 2001 to October 2003, 69 patients received covered Wallstent placement (Group 1). Thereafter, we modified our stent insertion method and 69 patients received stent placement using this modified method from November 2003 to January 2007 (Group 2). The modified insertion method consists of endoscopic sphincterotomy carried out in patients without pancreatic duct invasion and longer stent placement with the center of the stent located in the center of the biliary stricture to prevent pancreatitis, kinking of the bile duct, and stent dislocation. A comparative analysis was carried out using prospectively collected data in these two cohorts.

RESULTS

Tumor ingrowth was not observed, and stent occlusion rate was 18.8% in Group 1 and 23.2% in Group 2. The overall rates of stent-related complications did not differ (39.1% in Group 1 and 30.4% in Group 2), but stent-related complications within 3months decreased from 22 episodes in Group 1 to 13 episodes in Group 2. Median event-free survival was prolonged by modified stent insertion method (125days in Group 1 and 268days in Group 2, P=0.020), although cumulative survival and stent patency were not significantly different.

CONCLUSIONS

Our modified method of covered Wallstent placement showed improved event-free survival.

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.

Covered versus uncovered self-expandable nitinol stents in the palliative treatment of malignant distal biliary obstruction: results from a randomized, multicenter study

BACKGROUND

Covered biliary metal stents have been developed to prevent tumor ingrowth. Previous comparative studies are limited and often include few patients.

OBJECTIVE

To compare differences in stent patency, patient survival, and complication rates between covered and uncovered nitinol stents in patients with malignant biliary obstruction.

DESIGN

Randomized, multicenter trial conducted between January 2006 and October 2008.

SETTING

Ten sites serving a total catchment area of approximately 2.8 million inhabitants.

PATIENTS

A total of 400 patients with unresectable distal malignant biliary obstruction.

INTERVENTIONS

ERCP with insertion of covered or uncovered metal stent. Follow-up conducted monthly for symptoms indicating stent obstruction.

MAIN OUTCOME MEASUREMENTS

Time to stent failure, survival time, and complication rate.

RESULTS

The patient survival times were 116 days (interquartile range 242 days) and 174 days (interquartile range 284 days) in the covered and uncovered stent groups, respectively (P = .320). The first quartile stent patency time was 154 days in the covered stent group and 199 days in the uncovered stent group (P = .326). There was no difference in the incidence of pancreatitis or cholecystitis between the 2 groups. Stent migration occurred in 6 patients (3%) in the covered group and in no patients in the uncovered group (P = .030).

LIMITATIONS

Randomization was not blinded.

CONCLUSIONS

There were no significant differences in stent patency time, patient survival time, or complication rates between covered and uncovered nitinol metal stents in the palliative treatment of malignant distal biliary obstruction. However, covered stents migrated significantly more often compared with uncovered stents, and tumor ingrowth was more frequent in uncovered stents.

Mortality in patients undergoing covered self-expandable metal stent revisions in malignant biliary stricture: does pathology matter?

BACKGROUND AND AIMS

Partially covered metal stents have been extensively used for palliation of obstructive jaundice in malignant distal biliary strictures and can be removed in cases of malfunction or need for tissue diagnosis. We investigated independent predictors of mortality in patients undergoing partially covered metal stents revision (i.e., removal and replacement).

METHODS

Patients with a distal malignant biliary obstruction palliated with a partially covered metal stent were followed-up prospectively over 5 years until malfunction or death. All patients who required removal of their partially covered metal stents were captured in a specific database. Multivariate analysis was performed on non-surgical patients to assess for independent predictors of death using known risk factors including type of malignancy (adenocarcinoma versus all others), age greater than 55, gender, and exposure to adjuvant chemotherapy and/or radiotherapy.

RESULTS

Forty-two patients (28 men, mean age of 62±12 years) underwent partially covered metal stents removal. Of these, biliary drainage was achieved in 38 patients by placement of a new partially covered metal stent (n=32) or plastic stent (n=6). The remaining 4 patients did not undergo stent replacement because of refusal (2), resolution of obstruction (1) and unrelated death (1). Long-term follow-up post removal in patients who were not surgical candidates (n=31) was 35 weeks (95% CI 28-40), with a survival rate of 29% at 10 months. Logistic regression analysis in the 31 patients with unresectable disease showed that a histologic diagnosis of adenocarcinoma was associated with increased mortality post partially covered metal stents revision.

CONCLUSIONS

Partially covered metal stents revision should be undertaken especially when dealing with a non-adenocarcinoma type cancer.

A randomized trial comparing uncovered and partially covered self-expandable metal stents in the palliation of distal malignant biliary obstruction

BACKGROUND

The most common complication of uncovered biliary self-expandable metal stents (SEMSs) is tumor ingrowth. The addition of an impenetrable covering may prolong stent patency.

OBJECTIVE

To compare stent patency between uncovered and partially covered SEMSs in malignant biliary obstruction.

DESIGN

Multicenter randomized trial.

SETTING

Four teaching hospitals.

PATIENTS

Adults with inoperable distal malignant biliary obstruction.

INTERVENTIONS

Uncovered or partially covered SEMS insertion.

MAIN OUTCOME MEASURES

Time to recurrent biliary obstruction, patient survival, serious adverse events, and mechanism of recurrent biliary obstruction.

RESULTS

From October 2002 to May 2008, 129 patients were randomized. Recurrent biliary obstruction was observed in 11 of 61 uncovered SEMSs (18%) and 20 of 68 partially covered SEMSs (29%). The median times to recurrent biliary obstruction were 711 days and 357 days for the uncovered and partially covered SEMS groups, respectively (P = .530). Median patient survival was 239 days for the uncovered SEMS and 227 days for the partially covered SEMS groups (P = .997). Serious adverse events occurred in 27 (44%) and 42 (62%) patients in the uncovered and partially covered SEMS groups, respectively (P = .046). None of the uncovered and 8 (12%) of the partially covered SEMSs migrated (P = .0061).

LIMITATIONS

Intended sample size was not reached. Allocation to treatment groups was unequal.

CONCLUSIONS

There was no significant difference in time to recurrent biliary obstruction or patient survival between the partially covered and uncovered SEMS groups. Partially covered SEMSs were associated with more serious adverse events, particularly migration.

Role of endoscopic retrograde cholangiopancreatography in pancreatic diseases

Over the last 15 years, endoscopic retrograde cholangiopancreatography (ERCP) has evolved from a diagnostic tool to one that is primarily used to provide therapy. This development occurred first for biliary disorders and subsequently to a lesser extent for pancreatic diseases. Computed tomography, magnetic resonance imaging, magnetic resonance cholangiopancreatography and endoscopic ultrasonography suggest a diagnosis in the majority of patients with pancreatic diseases today and can help physicians and patients avoid unnecessary ERCP. However, a selected number of patients with pancreatic diseases may benefit from pancreatic endotherapy and avoid complex surgery and chronic use of medications. Pancreatic sphincterotomy, pancreatic stenting and pancreatic cyst drainage are some of the most effective and challenging endoscopic pancreatic interventions and should be performed with caution by expert therapeutic endoscopists. There has been a paucity of randomized studies investigating endoscopic techniques in comparison with surgery and medical therapy for the treatment of most benign and malignant pancreatic disorders due to the limited number of patients and the expertise required to attempt these procedures.

Gallbladder stent placement for prevention of cholecystitis in patients receiving covered metal stent for malignant obstructive jaundice: a feasibility study

PURPOSE

Covered self-expanding metal stents (CSEMS) have been used for palliation of malignant distal biliary strictures. Occlusion of the cystic duct by CSEMS may be complicated by cholecystitis. This potentially could be prevented by placement of a transpapillary gallbladder stent (GBS).

PATIENTS AND METHODS

Between 11/2006 and 10/2007, a total of 73 patients (50 male) aged 65 +/- 14 years underwent CSEMS placement for palliation of malignant obstructive jaundice. In cases where CSEMS placement caused occlusion of the cystic duct, a 7 French transpapillary pigtail gallbladder stent (GBS) was inserted to prevent cholecystitis.

RESULTS

Of the 73 patients, 18 had a prior cholecystectomy; 34 had the CSEMS placed below the cystic duct insertion. In 19 out of the 21 patients who had a CSEMS covering the cystic duct ostium, GBS placement was attempted, which was successful in 11 individuals (58%). An attempt to access the gallbladder was complicated by wire perforation of the cystic duct in three patients; one patient requiring emergent cholecystostomy tube placement. None of the patients who underwent successful GBS placement developed cholecystitis. One GBS dislodged and was repositioned. Cholecystitis occurred in two (20%) of the ten patients without transpapillary gallbladder decompression who had a CSEMS covering the cystic duct.

CONCLUSIONS

The ideal placement of a CSEMS is below the cystic duct insertion. Should the cystic duct ostium be occluded, placement of a GBS should be considered to minimize the risk of cholecystitis.

Bridge to surgery using partially covered self-expandable metal stents (PCMS) in malignant biliary stricture: an acceptable paradigm?

BACKGROUND AND AIM

Partially covered self-expanding metal stents (PCMS) have been extensively used for palliation of malignant distal biliary stricture. Many centers have been using them as a bridge to surgery (BTS) regardless of resectability with or without eventual neoadjuvant therapy. We analyzed the outcome of all patients receiving PCMS and subsequently referred for surgery in our institution.

METHODS

Our prospectively established pancreaticobiliary database was retrospectively analyzed to retrieve all patients with malignant biliary stricture who underwent PCMS placement and subsequently went for curative surgical attempt at our institution. Cancer type and staging, adverse events related to stent placement or surgery, type of surgery performed, time between stenting and surgery, length of postoperative hospitalization, and postoperative follow-up were recorded.

RESULTS

27 patients (21 men; median age 66 years, range 39-82 years) received PCMS. Indications for placement included biliary stricture related to pancreatic cancer (n=23) or other malignancies (n=4). Median time between stenting and surgery was 32 days (range 6-569 days). Median time of hospitalization post surgery was 7 days (1-40 days). All patients underwent exploratory laparoscopy, followed in 9 (33.3%) by Whipple procedure with uneventful removal of the PCMS. Eighteen patients (66.6%) had their attempted curative resection terminated early due to intraoperative evidence of metastatic spread, with 8 (30%) patients undergoing peritoneal or liver metastasis biopsy. PCMS were left in place in those 18 patients. Complications related to PCMS in the bridge-to-surgery period included migration (n=2, 7.4%) and tissue overgrowth (n=1, 3.4%), all of them managed by endoscopic removal and replacement with PCMS. Median follow-up post surgery was 210 days (range 9-1,642 days).

CONCLUSION

PCMS are an appropriate BTS option. For resectable patients, PCMS results in biliary drainage and allows for neoadjuvant treatment without portending subsequent curative resection (Whipple). For unresectable patients, long-term biliary drainage is provided by PCMS.

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.

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.

Covered Wallstents for palliation of malignant biliary obstruction: primary stent placement versus reintervention

BACKGROUND

Covered self-expandable metallic stents (SEMSs) are designed to prevent tumor ingrowth and can be removed if necessary. Only limited comparative data are available on the performance of covered SEMSs after primary placement versus reintervention.

OBJECTIVE

To assess the effectiveness and safety of covered SEMS placement either as primary treatment or reintervention in patients requiring palliation of malignant biliary obstruction.

DESIGN

Retrospective clinical cohort study.

SETTING

Tertiary referral center.

PATIENTS

This study involved 104 patients with unresectable malignant biliary strictures.

INTERVENTION

Covered biliary SEMS placement.

MAIN OUTCOME MEASUREMENTS

Stent patency, technical success, and patient survival.

RESULTS

Covered SEMSs were placed as primary treatment in 48 patients (46%), and reintervention was performed in 56 patients (54%). At 3, 6, and 12 months thereafter, the Kaplan-Meier estimated fractions of all patients with patent stents were 94%, 84%, and 58%, respectively. Covered SEMSs remained patent until the patient's death in 75 of 89 nonsurvivors (84%). Although patency rates 3, 6, and 12 months after primary placement (100%, 93%, and 82%, respectively) were higher than those after reintervention (90%, 78%, and 48%, respectively), the differences were not statistically significant (P = .057). Overall, the most frequent adverse events were cholangitis (7%) and stent migration (4%).

LIMITATIONS

The distribution of stricture locations differed among the groups, and survival data suggested the presence of more extensive disease in the primary treatment group at baseline.

CONCLUSION

The clinical utility and safety of primary covered SEMS placement were confirmed. This study provides the most extensive evidence to date that reintervention with a covered SEMS can provide a useful palliative option.

Reflux of duodenal contents and cholangitis in patients undergoing self-expanding metal stent placement

BACKGROUND

It has been reported that the occurrence of acute cholangitis is common, especially when the self-expanding metal stent (SEMS) is placed across the main duodenal papilla.

OBJECTIVE

To determine the incidence of duodenobiliary reflux and acute cholangitis after placement of SEMSs across the main duodenal papilla.

DESIGN

A prospective study.

SETTING

A tertiary-care teaching hospital.

PATIENTS

One hundred consecutive patients with malignant bile-duct obstruction.

INTERVENTIONS

A barium meal examination was performed 21 days after placement of SEMSs. Reflux of barium was monitored by using fluoroscopy. The patients were also monitored for the occurrence of fever. Serum bilirubin, alanine aminotransferase, alkaline phosphatase, and total and differential leukocyte counts were evaluated before and after the barium study.

MAIN OUTCOME MEASUREMENTS

The occurrence of duodenobiliary reflux and acute cholangitis.

RESULTS

Two patients developed acute cholangitis because of the failure of the function of the SEMS, and they died during the first week. Severe reflux of barium was evident in all the patients. However, none of them developed features of acute cholangitis because of reflux. After a mean (SD) follow-up of 6.4 +/- 1 months, 6 patients developed acute cholangitis because of blockage of the SEMS from ingrowth of tumor or collection of debris at the lower end of the SEMS.

LIMITATIONS

Unblinded study.

CONCLUSIONS

After placement of SEMSs across the main duodenal papilla, reflux of duodenal contents is a universal phenomenon. Acute cholangitis was observed only in cases with blockage of the SEMS from tumor ingrowth or debris.

[New techniques to extract impacted partially covered metallic biliary stents]

One of the problems affecting metallic biliary stents is the difficulty of removing them, especially after a period of months or if they have migrated. Several approaches have been used to remove both covered and uncovered stents, although with different degrees of effectiveness. We report two new approaches to removing partially covered stents that migrated proximally and that impacted in the papillary area and distal common bile duct. One stent was removed by papillectomy and the other by using duodenoscopy-guided controlled radial expansion balloon dilation. In both cases, the stents were removed without severe complications for the patient, leaving a good caliber in the stenosis.

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.

Percutaneous treatment of malignant jaundice due to extrahepatic cholangiocarcinoma: covered Viabil stent versus uncovered Wallstents

To compare clinical effectiveness of Viabil-covered stents versus uncovered metallic Wallstents, for palliation of malignant jaundice due to extrahepatic cholangiocarcinoma, 60 patients were enrolled in a prospective and randomized study. In half of the patients a bare Wallstent was used, and in the other half a Viabil biliary stent. Patients were followed up until death. Primary patency, survival, complication rates, and mean cost were calculated in both groups. Stent dysfunction occurred in 9 (30%) patients in the bare stent group after a mean period of 133.1 days and in 4 (13.3%) patients in the covered stent group after a mean of 179.5 days. The incidence of stent dysfunction was significantly lower in the covered stent group (P = 0.046). Tumor ingrowth occurred exclusively in the bare stent group (P = 0.007). Median survival was 180.5 days for the Wallstent and 243.5 days for the Viabil group (P = 0.039). Complications and mean cost were similar in the two groups. Viabil stent-grafts proved to be significantly superior to Wallstents for the palliation of malignant jaundice due to extrahepatic cholangiocarcinoma, with comparable cost and complication rates. Appropriate patient selection should be performed prior to stent placement.