Management of distal malignant biliary obstruction with the ComVi stent, a new covered metallic stent. Surg Endosc. 2010;24:131-137. [PMID: 19517184 DOI: 10.1007/s00464-009-0537-9]

Efficacy and safety of a novel polytetrafluoroethylene-coated self-expandable metal stent for distal malignant biliary obstruction

Background

Stent migration and sludge formation remain significant problems associated with covered self-expandable metal stents (CSEMSs). The EGIS biliary stent fully covered flare type (EGIS biliary stent), a new type of polytetrafluoroethylene-coated self-expandable metal stent with low axial force and an anti-migration system, was developed to overcome these disadvantages. We conducted this study to evaluate the efficacy and safety of this stent in comparison with conventional CSEMS (c-CSEMS).

Methods

We retrospectively analyzed consecutive patients with unresectable pancreatic cancer who received initial CSEMS for distal malignant biliary obstruction. The primary outcome was time to recurrent biliary obstruction (RBO). Secondary outcomes included technical success rate, functional success rate, stent-related adverse events, causes of RBO, and re-intervention.

Results

A total of 40 patients were included (EGIS group: 20; c-CSEMS group: 20). The technical and functional success rates were similar between the two groups. Stent-related adverse event rates (20% vs. 15%, p > 0.99) and overall RBO rates (56% vs. 50%, p > 0.99) were not significantly different between the two groups. Stent migration was the most common cause of RBO in the EGIS group, while stent occlusion was in the c-CSEMS group. The median time to RBO (102 vs. 434 days, p = 0.10) was not significantly different between the two groups. Endoscopic transpapillary re-intervention was successful in most patients in both groups.

Conclusions

The EGIS biliary stent was not associated with a longer time to RBO compared to c-CSEMS. Further improvements, especially against stent migration, are needed to improve its efficacy.

Covered Versus Uncovered Metal Stents for the Drainage of the Malignant Distal Biliary Obstruction With ERCP: A Systematic Review and Meta-Analysis

INTRODUCTION AND AIM

Unresectable malignant distal biliary obstruction is a condition that should be treated with drainage and clearance of the biliary duct. self-expanded metal stents (SEMS) are known to be better and more effective than plastic stents because the patency is longer. The actual evidence is insufficient to recommend if it is better the use of SEMSu over SEMSc or vice versa for the drainage of the malignant distal biliary obstruction during ERCP. We performed a systematic review and meta-analyses to demonstrate if exists superiority between one or other type of SEMS performed by ERCP.

MATERIALS AND METHODS

We conducted a systematic review in different databases, such as PubMed, Cochrane, Medline, and OVID database. A search was made of all studies published up to May 2023.

RESULTS

Seven studies were analyzed. A total of 1070 patients were included. Of the total of patients, 48.9% were male. The cumulative stent patency, the failure rate, the survival probably and the adverse events rate, were similar between SEMSc and SEMSu groups. The stent migration rate was higher in the SEMSc group (RR=2.34 [95% CI: 1.35-4.08]). The tumor overgrowth was higher in the SEMSc group (RR=2.05 [95% CI: 1.13-3.72]). The tumor ingrowth was higher in the SEMSu group (RR=0.25 [95% CI: 0.11-0.61]).

CONCLUSIONS

The conclusions of our study show that there are no differences between the use of uncovered SEMS and covered SEMS for palliative treatment of distal biliopancreatic obstructions, and it has no impact on mortality or patient survival. New functional studies regarding the type of stent cover, radial force or length thereof are required.

Adverse events of self-expandable metal stent placement for malignant distal biliary obstruction: a large multicenter study

BACKGROUND AND AIMS

Endoscopic placement of self-expandable metal stents (SEMSs) for malignant distal biliary obstruction (MDBO) may be accompanied by several types of adverse events. The present study analyzed the adverse events occurring after SEMS placement for MDBO.

METHODS

The present study retrospectively investigated the incidence and types of adverse events in patients who underwent SEMS placement for MDBO between April 2018 and March 2021 at 26 hospitals. Risk factors for acute pancreatitis, cholecystitis, and recurrent biliary obstruction (RBO) were evaluated by univariate and multivariate analyses.

RESULTS

Of the 1425 patients implanted with SEMSs for MDBO, 228 (16.0%) and 393 (27.6%) experienced early adverse events and RBO, respectively. Pancreatic duct without tumor involvement (P = .023), intact papilla (P = .025), and SEMS placement across the papilla (P = .037) were independent risk factors for acute pancreatitis. Tumor involvement in the orifice of the cystic duct was an independent risk factor for cholecystitis (P < .001). Use of fully and partially covered SEMSs was an independent risk factor for food impaction and/or sludge. Use of fully covered SEMSs was an independent risk factor for stent migration. Use of uncovered SEMSs and laser-cut SEMSs was an independent risk factor for tumor ingrowth.

CONCLUSIONS

Pancreatic duct without tumor involvement, intact papilla, and SEMS placement across the papilla were independent risk factors for acute pancreatitis, and tumor involvement in the orifice of the cystic duct was an independent risk factor for cholecystitis. The risk factors for food impaction and/or sludge, stent migration, and tumor ingrowth differed among types of SEMSs.

Efficacy of a novel self-expandable metal stent with dumbbell-shaped flare ends for distal biliary obstruction due to unresectable pancreatic cancer

This study aimed to evaluate the efficacy of a novel fully covered self-expandable metal stent (SEMS) with dumbbell-shaped flare ends for the palliation of distal biliary obstruction (DBO) due to unresectable pancreatic cancer (UPC). Patients with DBO due to UPC who received the novel HILZO fully covered stent (HFS), the WALLFLEX partially covered stent (WPS) or fully covered stent (WFS) were analyzed. The incidence of recurrent biliary obstruction (RBO), time to RBO (TRBO), and the incidence of complications were compared among the three SEMS groups. Eighty-four patients (HFS, n = 36; WPS, n = 20; WFS, n = 28) were included. The incidence of RBO was low in the HFS group (versus the WPS and WFS group, p = 0.033 and 0.023, respectively). TRBO in the HFS group was longer than that in the WFS group (p = 0.049). Placement of the HFS was an independent factor for long TRBO in multivariable analysis (p = 0.040). The incidence of pancreatitis and cholecystitis in the HFS group was low (one for each). It is recommended to use the HFS for the palliation of DBO due to UPC from the viewpoint of the low incidence of RBO and complications.

Layered Double Hydroxide-Based Micro "Chemical Factory" with Arsenic Processing and Screening Functions on Nitinol for Gallbladder Cancer Treatment

Gallbladder cancer is a common malignant tumor of the biliary system with a high fatality rate. Nitinol (Ni-Ti) stents, a standard treatment for prolonging patients' lives, are susceptible to reocclusion and cannot inhibit tumor recurrence because they lack antitumor and antibacterial activity. Herein, an arsenic-loaded layered double-hydroxide film is constructed on Ni-Ti, forming a micro "chemical factory." The LDH plays the role of a "processer" which absorbs highly toxic trivalent arsenic (As(III)) and processes it into lowly toxic pentavalent arsenic (As(V)). It also acts as a "quality-inspector," confining As(III) in the interlayer and releasing only As(V) (the finished product) to the outside. This control mechanism minimizes the toxicity during contact with normal tissue. The acidic microenvironment and overexpression of glutathione in tumor tissues not only accelerates the release of arsenic from the platform but also triggers the in situ transformation of arsenic from lowly toxic As(V) to highly toxic As(III), exerting a strong arsenic-mediated antineoplastic effect. Such a microenvironment-responsive "chemical factory" with arsenic processing and screening functions is expected to prevent tumor overgrowth, metastasis, and bacterial infection and provide new insights into the design of Ni-Ti drug-eluting stents for gallbladder cancer treatment.

Comparison of three different self-expanding metal stents using rabbit models for the treatment of tracheal collapse

Purpose:

To identify an optimal self-expandable metallic stent (SEMS) and verify whether a mechanically superior SEMS would result in better clinical outcomes in the treatment of tracheal collapse.

Methods:

We selected three SEMS (n = 8 each), including an S-type stent with a wire diameter of 0.006 inches (S6) and two D-type stents with wire diameters of 0.006 (D6) and 0.007 inches (D7). Twenty-four New Zealand White rabbits were divided into three equal groups. After the stents were deployed, the clinical signs were recorded daily, and radiographic examinations were performed monthly. All rabbits were euthanized after three months.

Results:

Two rabbits with S6 stents and one rabbit with a D7 stent died within three months because of stent migration or pneumonia. All rabbits with D6 stents survived for three months. On histological examination, the D6 group had the lowest inflammation score.

Conclusions:

Both clinically and histopathologically, the results with D-type stents with a wire diameter of 0.006 inches were superior to those of the other groups (p = 0.001). The use of an optimal intraluminal stent may improve the long-term clinical outcomes in the treatment of tracheal collapse in dogs.

Design and Optimization of a New Anti-reflux Biliary Stent With Retractable Bionic Valve Based on Fluid-Structure Interaction Analysis

Duodenal biliary reflux has been a challenging common problem which could cause dreadful complications after biliary stent implantation. A novel anti-reflux biliary stent with a retractable bionic valve was proposed according to the concertina motion characteristics of annelids. A 2D equivalent fluid-structure interaction (FSI) model based on the axial section was established to analyze and evaluate the mechanical performances of the anti-reflux biliary stent. Based on this model, four key parameters (initial shear modulus of material, thickness, pitch, and width) were selected to investigate the influence of design parameters on anti-reflux performance via an orthogonal design to optimize the stent. The results of FSI analysis showed that the retrograde closure ratio of the retractable valve primarily depended on initial shear modulus of material (p < 0.05) but not mainly depended on the thickness, pitch, and width of the valve (p > 0.05). The optimal structure of the valve was finally proposed with a high retrograde closing ratio of 95.89%. The finite element model revealed that the optimized anti-reflux stent possessed improved radial mechanical performance and nearly equal flexibility compared with the ordinary stent without a valve. Both the FSI model and experimental measurement indicated that the newly designed stent had superior anti-reflux performance, effectively preventing the duodenobiliary reflux while enabling the bile to pass smoothly. In addition, the developed 2D equivalent FSI model provides tremendous significance for resolving the fluid-structure coupled problem of evolution solid with large deformation and markedly shortens the calculation time.

Malignant biliary obstruction due to metastatic non-hepato-pancreato-biliary cancer

Malignant biliary obstruction generally results from primary malignancies of the pancreatic head, bile duct, gallbladder, liver, and ampulla of Vater. Metastatic lesions from other primaries to these organs or nearby lymph nodes are rarer causes of biliary obstruction. The most common primaries include renal cancer, lung cancer, gastric cancer, colorectal cancer, breast cancer, lymphoma, and melanoma. They may be difficult to differentiate from primary hepato-pancreato-biliary cancer based on imaging studies, or even on biopsy. There is also no consensus on the optimal method of treatment, including the feasibility and effectiveness of endoscopic intervention or surgery. A thorough review of the literature on pancreato-biliary metastases and malignant biliary obstruction due to metastatic non-hepato-pancreato-biliary cancer is presented. The diagnostic modality and clinical characteristics may differ significantly depending on the type of primary cancer. Different primaries also cause malignant biliary obstruction in different ways, including direct invasion, pancreatic or biliary metastasis, hilar lymph node metastasis, liver metastasis, and peritoneal carcinomatosis. Metastasectomy may hold promise for some types of pancreato-biliary metastases. This review aims to elucidate the current knowledge in this area, which has received sparse attention in the past. The aging population, advances in diagnostic imaging, and improved treatment options may lead to an increase in these rare occurrences going forward.

Long-term outcomes of fully covered self-expandable metal stents versus plastic stents in chronic pancreatitis

Chronic pancreatitis (CP) related main pancreatic duct (MPD) stricture has been a challenge for endoscopists. Fully covered self-expandable metal stents (FC-SEMS) has been tried in CP patients, but the efficacy and safety are still controversial. Thus, we aim to compare the long-term clinical efficacy of FC-SEMS vs. plastic stent placement in persistent MPD strictures secondary to CP. Between 2007 and 2018, 80 chronic pancreatitis patients (58 males, median age 49 years), who underwent endoscopic placement of FC-SEMS (n = 26) and plastic stent (n = 54) for persistent MPD strictures after at least 3 months of initial single plastic stenting, were retrospectively analyzed during a median follow-up duration of 33.7 months. As a result, MPD stricture resolution rate was statistically higher in FC-SEMS group (87.0% vs. 42.0%, p < 0.001). Although immediate complications occurred similarly (38.5% vs. 37.0%, p = 0.902), spontaneous migration (26.9%) and de novo strictures (23.1%) were pronounced delayed complications in FC-SEMS group. Pain relief during follow-up was significantly higher in FC-SEMS group (76.9% vs. 53.7%, p = 0.046). The total procedure cost was similar in both groups ($1,455.6 vs. $1,596.9, p = 0.486). In comparison with plastic stent, FC-SEMS placement for persistent MPD strictures had favorable long-term clinical efficacy, with its typical complications like spontaneous migration and de novo strictures.

Design and evaluation of a novel anti-reflux biliary stent with cone spiral valve

Endoscopic placement of biliary stent is a well-established palliative treatment for biliary obstruction. However, duodenobiliary reflux after stent placement has been a common problem which may lead to dreadful complications. This paper designed a novel anti-reflux biliary stent with a cone spiral valve. Fluid-Structure Interaction (FSI) simulations were established to evaluate the efficiency of the anti-reflux stent comparing with a clinically applied standard stent. According to the stress distribution of the valve, the fatigue performance in the stress concentration area was analyzed. The results show that when the antegrade flow through the valve, the cone spiral valve could stretch and open to realize adequate drainage under the normal physiological pressure of biliary tract; When the duodenal reflux through the valve, the valve would be compressed and close with a result of nearly zero at the outlet flow rate. Furthermore, the anti-reflux stent achieved improved radial mechanical performance with 2.7 times higher radial stiffness than standard stent. Finite element analysis (FEA) also indicates that compared with the standard stent, the addition of the anti-reflux valve had little negative effect on flexibility of the stent. Fatigue analysis results showed that the valve was reliable. This research provides the new stent with a cone spiral valve and proves that it is technically feasible and effective for preventing the duodenobiliary reflux while ensuring the antegrade bile flow without compromising the other biomechanical performances.

Feasibility and efficacy evaluation of metallic biliary stents eluting gemcitabine and cisplatin for extrahepatic cholangiocarcinoma

BACKGROUND

Effective endoscopic management is fundamental for the treatment of extrahepatic cholangiocarcinoma (ECC). However, current biliary stents that are widely used in clinical practice showed no antitumor effect. Drug-eluting stents (DESs) may achieve a combination of local chemotherapy and biliary drainage to prolong stent patency and improve prognosis.

AIM

To develop novel DESs coated with gemcitabine (GEM) and cisplatin (CIS)-coloaded nanofilms that can maintain the continuous and long-term release of antitumor agents in the bile duct to inhibit tumor growth and reduce systemic toxicity.

METHODS

Stents coated with different drug-eluting components were prepared by the mixed electrospinning method, with poly-L-lactide-caprolactone (PLCL) as the drug-loaded nanofiber membrane and GEM and/or CIS as the antitumor agents. Four different DESs were manufactured with four drug-loading ratios (5%, 10%, 15%, and 20%), including bare-loaded (PLCL-0), single-drug-loaded (PLCL-GEM and PLCL-CIS), and dual-drug-loaded (PLCL-GC) stents. The drug release property, antitumor activity, and biocompatibility were evaluated in vitro and in vivo to confirm the feasibility and efficacy of this novel DES for ECC.

RESULTS

The in vitro drug release study showed the stable, continuous release of both GEM and CIS, which was sustained for over 30 d without an obvious initial burst, and a higher drug-loaded content induced a lower release rate. The drug-loading ratio of 10% was used for further experiments due to its ideal inhibitory efficiency and relatively low toxicity. All drug-loaded nanofilms effectively inhibited the growth of EGI-1 cells in vitro and the tumor xenografts of nude mice in vivo; in addition, the dual-loaded nanofilm (PLCL-GC) had a significantly better effect than the single-drug-loaded nanofilms (P < 0.05). No significant differences in the serological analysis (P > 0.05) or histopathological changes were observed between the single-loaded and drug-loaded nanofilms after stent placement in the normal porcine biliary tract.

CONCLUSION

This novel PLCL-GEM and CIS-eluting stent maintains continuous, stable drug release locally and inhibits tumor growth effectively in vitro and in vivo. It can also be used safely in normal porcine bile ducts. We anticipate that it might be considered an alternative strategy for the palliative therapy of ECC patients.

Comparison of different types of covered self-expandable metal stents for malignant colorectal obstruction

BACKGROUND

Stent migration is one of the main drawbacks of covered self-expandable metal stent (SEMSs), occurring in up to 40% of malignant colorectal obstruction management cases. Various types of covered SEMSs have been developed to reduce this risk. We aimed to compare the effectiveness and complication rates of the flare-type covered SEMS (Flare) with those of the double-layered covered SEMS (ComVi).

METHODS

We performed a prospective, randomized study in four tertiary referral centers between July 2016 and April 2018. Patients with malignant colorectal obstruction were eligible for the study. The primary outcome was migration rate as observed within the first month. Rates of technical success, clinical success, and complications within the first month were also assessed.

RESULTS

A total of 60 patients were included (mean age, 70.5 ± 12.5 years; male, 31 [51.7%]). Flare and ComVi stents were applied in 30 patients each. The Flare and ComVi groups showed comparable technical success rates (90% [27/30] vs. 96.7% [29/30], p = 0.605) and clinical success rates (85.2% [23/27] vs. 75.9% [22/29], p = 0.589). Migration occurred in three (11.1%) and four (13.8%) cases in the Flare and ComVi groups, respectively, without significant difference (p = 0.99), and the risk of other complications, including perforation and re-obstruction, did not differ between the two groups.

CONCLUSIONS

Our study indicates that both flare-shape and double-layered covered SEMSs are equally effective options for the management of malignant colorectal obstruction with low migration rates when compared with previously reported migration risk of covered SEMS.

Antireflux covered metal stent for nonresectable distal malignant biliary obstruction: Multicenter randomized controlled trial

BACKGROUND AND AIM

An antireflux metal stent (ARMS) for nonresectable distal malignant biliary obstruction (MBO) may prevent recurrent biliary obstruction (RBO) as a result of duodenobiliary reflux and prolong time to RBO (TRBO). Superiority of ARMS over conventional covered self-expandable metal stents (SEMS) has not been fully examined.

METHODS

We conducted a multicenter randomized controlled trial to examine whether TRBO of an ARMS with a funnel-shaped valve was longer than that of a covered SEMS in SEMS-naïve patients. We enrolled 104 patients (52 patients per arm) at 11 hospitals in Japan. Secondary outcomes included causes of RBO, adverse events, and patient survival.

RESULTS

TRBO did not differ significantly between the ARMS and covered SEMS groups (median, 251 vs 351 days, respectively; P = 0.11). RBO as a result of biliary sludge or food impaction was observed in 13% and 9.8% of patients who received an ARMS and covered SEMS, respectively (P = 0.83). ARMS was associated with a higher rate of stent migration compared with the covered SEMS (31% vs 12%, P = 0.038). Overall rates of adverse events were 20% and 18% in the ARMS and covered SEMS groups, respectively (P = 0.97). No significant between-group difference in patient survival was observed (P = 0.26).

CONCLUSIONS

The current ARMS was not associated with longer TRBO compared with the covered SEMS. Modifications including addition of an anti-migration system are required to use the current ARMS as first-line palliative treatment of distal MBO (UMIN-CTR clinical trial registration number: UMIN000014784).

Efficacy of a Multiplex Paclitaxel Emission Stent Using a Pluronic® Mixture Membrane versus a Covered Metal Stent in Malignant Biliary Obstruction: A Prospective Randomized Comparative Study

Background/Aims

A drug-eluting stent for unresectable malignant biliary obstruction was developed to increase stent patency by preventing tumor ingrowth. The safety and efficacy of a new generation of metallic stents covered with a paclitaxel-incorporated membrane using a Pluronic^® mixture (MSCPM-II) were compared prospectively with those of covered metal stents (CMSs) in patients with malignant biliary obstructions.

Methods

This study was initially designed as a prospective randomized trial but was closed early because of a high incidence of early occlusion. Therefore, the data were analyzed using the intent-to-treat method. A total of 72 patients with unresectable distal malignant biliary obstructions were prospectively enrolled.

Results

The two groups did not differ significantly in basic characteristics and mean follow-up period (MSCPM-II 194 days vs CMS 277 days, p=0.063). Stent occlusion occurred in 14 patients (35%) who received MSCPM-II and in seven patients (21.9%) who received CMSs. Stent patency and survival time did not significantly differ between the two groups (p=0.355 and p=0.570). The complications were mild and resolved by conservative management in both groups.

Conclusions

There were no significant differences in stent patency or patient survival in MSCPM-II and CMS patients with malignant biliary obstructions.

Antireflux Metal Stent for Initial Treatment of Malignant Distal Biliary Obstruction

Objectives

To compare the use of an antireflux metal stent (ARMS) with that of a conventional covered self-expandable metal stent (c-CSEMS) for initial stenting of malignant distal biliary obstruction (MDBO).

Materials and Methods

We retrospectively investigated 59 consecutive patients with unresectable MDBO undergoing initial endoscopic biliary drainage. ARMS was used in 32 patients and c-CSEMS in 27. Technical success, functional success, complications, causes of recurrent biliary obstruction (RBO), time to RBO (TRBO), and reintervention were compared between the groups.

Results

Stent placement was technically successful in all patients. There were no significant intergroup differences in functional success (ARMS [96.9%] versus c-CSEMS [96.2%]), complications (6.2 versus 7.4%), and RBO (48.4 versus 42.3%). Food impaction was significantly less frequent for ARMS than for c-CSEMS (P = 0.037), but TRBO did not differ significantly between the groups (log-rank test, P = 0.967). The median TRBO was 180.0 [interquartile range (IQR), 114.0–349.0] days for ARMS and 137.0 [IQR, 87.0–442.0] days for c-CSEMS. In both groups, reintervention for RBO was successfully completed in all patients thus treated.

Conclusion

ARMS offers no advantage for initial stent placement, but food impaction is significantly prevented by the antireflux valve.

Antireflux Metal Stent as a First-Line Metal Stent for Distal Malignant Biliary Obstruction: A Pilot Study

Background/Aims

In distal malignant biliary obstruction, an antireflux metal stent (ARMS) with a funnel-shaped valve is effective as a reintervention for metal stent occlusion caused by reflux. This study sought to evaluate the feasibility of this ARMS as a first-line metal stent.

Methods

Patients with nonresectable distal malignant biliary obstruction were identified between April and December 2014 at three Japanese tertiary centers. We retrospectively evaluated recurrent biliary obstruction and adverse events after ARMS placement.

Results

In total, 20 consecutive patients were included. The most common cause of biliary obstruction was pancreatic cancer (75%). Overall, recurrent biliary obstruction was observed in seven patients (35%), with a median time to recurrent biliary obstruction of 246 days (range, 11 to 246 days). Stent occlusion occurred in five patients (25%), the causes of which were sludge and food impaction in three and two patients, respectively. Stent migration occurred in two patients (10%). The rate of adverse events associated with ARMS was 25%: pancreatitis occurred in three patients, cholecystitis in one and liver abscess in one. No patients experienced non-occlusion cholangitis.

Conclusions

The ARMS as a first-line biliary drainage procedure was feasible. Because the ARMS did not fully prevent stent dysfunction due to reflux, further investigation is warranted.

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.

Reintervention for occluded metal stent in malignant bile duct obstruction: A prospective randomized trial comparing covered and uncovered metal stent

BACKGROUND AND AIM

No prospective data are available on comparing covered and uncovered self-expandable metal stent (SEMS) for reintervention of occluded uncovered metal stents during endoscopic retrograde cholangiopancreatography in patients with malignant distal biliary obstruction.

METHODS

From June 2010 to November 2014, 43 patients with inoperable distal biliary obstruction of a previously placed uncovered SEMS were enrolled from three centers in Korea and randomly assigned to covered (n = 22) or uncovered SEMS group (n = 21). The primary outcome was overall stent patency. Secondary outcome was time-to-stent occlusion, patient survival, cause of stent occlusion, and adverse events.

RESULTS

Overall median patency of secondary stent was 112.0 days. Median stent patency of covered and uncovered SEMS was 112.0 and 181.0 days, respectively, (P = 0.373). There was a tendency towards a longer time-to-stent occlusion in uncovered SEMS group (median: 112.0 vs 181.0 days). However, it did not reach statistical significance (P = 0.214). Most common causes of occlusion were stent clogging (36.4%) and tumor ingrowth (33.3%) in covered and uncovered SEMS groups, respectively. There was no significant difference in median survival between the groups (median: 308 vs 300 days; P = 0.325). Acute cholangitis occurred in four patients (three in covered vs one in uncovered SEMS group, P = 0.607).

CONCLUSIONS

In this exploratory trial, there were no statistically significant differences in stent patency, time-to-stent occlusion, patient survival, and complication rates between covered and uncovered SEMS groups. Larger confirmatory multicenter trial is needed for the clear conclusion (ClinicalTrials.gov: NCT01315522).

Basic Knowledge about Metal Stent Development

Biliary self-expandable metal stents (SEMS), a group of non-vascular stents, have been used in the palliative management of biliary obstruction around the world. However, there are still unmet needs in the clinical application of biliary SEMS. Comprehensive understanding of the SEMS is required to resolve the drawbacks and difficulties of metal stent development. The basic structure of SEMS, including the materials and knitting methods of metal wires, covering materials, and radiopaque markers, are discussed in this review. What we know about the physical and mechanical properties of the SEMS is very important. With an understanding of the basic knowledge of metal stents, hurdles such as stent occlusion, migration, and kinking can be overcome to develop more ideal SEMS.

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.

Covered versus Uncovered Self-Expandable Metal Stents for Managing Malignant Distal Biliary Obstruction: A Meta-Analysis

AIM

To compare the efficacy of using covered self-expandable metal stents (CSEMSs) and uncovered self-expandable metal stents (UCSEMSs) to treat objective jaundice caused by an unresectable malignant tumor.

METHODS

We performed a comprehensive electronic search from 1980 to May 2015. All randomized controlled trials comparing the use of CSEMSs and UCSEMSs to treat malignant distal biliary obstruction were included.

RESULTS

The analysis included 1417 patients enrolled in 14 trials. We did not detect significant differences between the UCSEMS group and the CSEMS group in terms of cumulative stent patency (hazard ratio (HR) 0.93, 95% confidence interval (CI) 0.19-4.53; p = 0.93, I2 = 0%), patient survival (HR 0.77, 95% CI 0.05-10.87; p = 0.85, I2 = 0%), overall stent dysfunction (relative ratio (RR) 0.85, M-H, random, 95% CI 0.57-1.25; p = 0.83, I2 = 63%), the overall complication rate (RR 1.26, M-H, fixed, 95% CI 0.94-1.68; p = 0.12, I2 = 0%) or the change in serum bilirubin (weighted mean difference (WMD) -0.13, IV fixed, 95% CI 0.56-0.3; p = 0.55, I2 = 0%). However, we did detect a significant difference in the main causes of stent dysfunction between the two groups. In particular, the CSEMS group exhibited a lower rate of tumor ingrowth (RR 0.25, M-H, random, 95% CI 0.12-0.52; p = 0.002, I2 = 40%) but a higher rate of tumor overgrowth (RR 1.76, M-H, fixed, 95% CI 1.03-3.02; p = 0.04, I2 = 0%). Patients with CSEMSs also exhibited a higher migration rate (RR 9.33, M-H, fixed, 95% CI 2.54-34.24; p = 0.008, I2 = 0%) and a higher rate of sludge formation (RR 2.47, M-H, fixed, 95% CI 1.36-4.50; p = 0.003, I2 = 0%).

CONCLUSIONS

Our meta-analysis indicates that there is no significant difference in primary stent patency and stent dysfunction between CSEMSs and UCSEMSs during the period from primary stent insertion to primary stent dysfunction or patient death. However, when taking further management for occluded stents into consideration, CSEMSs is a better choice for patients with malignant biliary obstruction due to their removability.

No benefit of endoscopic sphincterotomy before biliary placement of self-expandable metal stents for unresectable pancreatic cancer

BACKGROUND & AIMS

Endoscopic sphincterotomy (ES) is performed routinely before self-expandable metallic stents (SEMS) are placed in malignant distal biliary strictures to prevent postprocedural pancreatitis. However, it is not clear whether ES actually prevents pancreatitis or affects other adverse events (AEs). We conducted a noninferiority trial to examine the necessity of ES before SEMS placement.

METHODS

Two hundred patients with distal biliary strictures caused by unresectable pancreatic cancer were assigned randomly to groups that received ES or did not receive ES (non-ES) before SEMS placement, at 25 hospitals in Hokkaido, Japan, from August 2010 through November 2012. The primary outcome was early AEs (≤30 d) specifically related to the presence or absence of ES (pancreatitis, bleeding, or perforation). Secondary outcomes measured included the effect of ES omission on time to SEMS dysfunction and patient survival times.

RESULTS

The proportions of patients with early AEs were 9.2% in the non-ES group and 10.4% in the ES group (a difference of 1.2%, noninferior). The median times to SEMS dysfunction was longer than 594 days in the non-ES group and 541 days in the ES group (P = .88). The median overall survival times were 202 in the ES group vs 255 days in the non-ES group; P = .20).

CONCLUSIONS

ES before SEMS does not affect the incidence of AEs, SEMS patency, or patient survival times. Our data provide no evidence for a benefit of ES to patients undergoing SEMS placement for a biliary stricture caused by pancreatic cancer. UMIN clinical trials registry number: 000004044.

Treatment of distal cholangiocarcinoma

Distal cholangiocarcinoma (DCC) is a rare, aggressive malignancy with an increasing incidence during past few years. The great majority of distal bile duct cancers are adenocarcinomas that preferentially invade adjacent organs and metastasize to regional lymph nodes. Surgical resection remains the only potentially curative treatment at present. Nevertheless, resectability rates range from 21% to 96% either due to local vascular invasion or distant metastasis. Therefore, DCC is related with a poor prognosis. Thus, new treatments for DCC are becoming a hot spot of research in recent years. This article reviews the progress in the treatment of DCC in terms of radical surgery, palliative surgery and interventional therapy as well as adjuvant therapy.

Risk factors for covered metallic stent migration in patients with distal malignant biliary obstruction due to pancreatic cancer

BACKGROUND AND AIM

Covered metallic stents (CMSs) were developed to overcome tumor ingrowth in uncovered metallic stents (UMSs) for malignant biliary obstruction, but superiority of CMSs over UMSs is still controversial due to the high migration rate in CMS. Therefore, we conducted this retrospective analysis to clarify risk factors for stent migration, including mechanical properties of CMSs.

METHODS

Patients with unresectable pancreatic cancer, receiving CMS for distal malignant biliary obstruction in five tertiary care centers, were retrospectively studied. Univariate and multivariate analyses to identify prognostic factors for early (< 6 months) stent migration were performed using a proportional hazards model with death or stent occlusion without stent migration as a competing risk. Two mechanical properties were included in the analysis: axial force, the recovery force that leads to a CMS straightening, and radial force (RF), the expansion force against the stricture.

RESULTS

Among 290 patients who received CMS placement for distal malignant biliary obstruction, stent migration rate was 15.2%. CMS migrated early (< 6 months) in 10.0% and distally in 11.7%, respectively. In the multivariate analysis, significant risk factors for early stent migration were chemotherapy (subdistribution hazard ratios [SHR] 4.46, P = 0.01), CMS with low RF (SHR 2.23, P = 0.03), and duodenal invasion (SHR 2.25, P = 0.02).

CONCLUSION

CMS with low RF, chemotherapy, and duodenal invasion were associated with CMS migration from our study.

Transmural biliary drainage can be an alternative to transpapillary drainage in patients with an indwelling duodenal stent

BACKGROUND

Self-expandable metal stents (SEMS) are widely utilized to relieve symptoms of malignant gastric outlet obstruction (GOO), but GOO is frequently complicated by nonresectable distal biliary obstruction. The optimal endoscopic approach to biliary drainage in this setting remains controversial and has yet to be resolved.

AIMS

To compare the safety and efficacy of endoscopic ultrasound-guided transmural biliary drainage (EUS-BD) and transpapillary drainage in patients with an indwelling duodenal SEMS.

METHODS

Patients who underwent EUS-BD or transpapillary drainage for distal malignant biliary obstruction with an indwelling duodenal SEMS between June 2007 and August 2012 at three Japanese tertiary referral centers were identified retrospectively. We compared times to stent dysfunction, causes of dysfunction, and procedural related complications between these two groups.

RESULTS

Twenty patients were included in the study (7 EUS-BD and 13 transpapillary drainage). EUS-BD was performed via hepaticogastrostomy using a SEMS in three patients and via choledochoduodenostomy using a SEMS or a plastic stent in two patients each. Transpapillary drainage was performed using a SEMS in all patients. The stent patency rate in the EUS-BD group was higher than that in the transpapillary drainage group (100 vs. 71% at 1 month and 83 vs. 29% at 3 months, respectively). The rate of stent dysfunction in the EUS-BD group tended to be lower than that in the transpapillary group (14 vs. 54%; P = 0.157). Complication rates were similar between the groups (P = 1.000), with moderate bleeding in one patient in the EUS-BD group and mild pancreatitis in one patient in the transpapillary group.

CONCLUSION

Endoscopic ultrasound-guided transmural biliary drainage is an alternative to transpapillary drainage in patients with an indwelling duodenal SEMS.

Metallic stent with high axial force as a risk factor for cholecystitis in distal malignant biliary obstruction

BACKGROUND AND AIM

Tumor involvement to the orifice of cystic duct (OCD) is a risk factor for cholecystitis after self-expandable metallic stent (SEMS) placement, but its prevention is still difficult. We conducted this multicenter analysis to clarify a type of SEMS or a method to place SEMS which would decrease the incidence of cholecystitis after SEMS placement.

METHODS

The incidence of cholecystitis was studied in consecutive patients receiving SEMS for distal malignant biliary obstruction in five tertiary care centers. Multiple logistic regression analysis was performed to evaluate risk factors for cholecystitis.

RESULTS

A total of 376 patients who received SEMS placement for distal malignant biliary obstruction were analyzed. Tumor involvement to OCD was diagnosed in 25.3%. Overall incidence of cholecystitis was 6.9%. Cholecystitis was observed in 8.0% of 300 patients with covered SEMS, 16.8% of 95 patients with tumor involvement to OCD, 10.8% of 234 patients with SEMS of high axial force (AF), and 12.0% of 158 patients with SEMS length ≤ 60 mm. In the multivariate analysis, tumor involvement to OCD (odds ratio [OR] 5.40, P < 0.001), SEMSs with high AF (OR 5.33, P = 0.002), and SEMS length ≤ 60 mm (OR 3.19, P = 0.010) are risk factors. Among patients with tumor involvement to OCD, the incidence of cholecystitis in SEMS with high and low AF was 25.0% and 5.0%, respectively.

CONCLUSION

This study with an expanded cohort reconfirmed tumor involvement to OCD as a risk factor for cholecystitis after SEMS placement. SEMS with low AF might decrease cholecystitis.

Novel antireflux covered metal stent for recurrent occlusion of biliary metal stents: a pilot study

BACKGROUND

Feasibility of antireflux metal stent (ARMS), designed to prevent duodenobiliary reflux, was reported in patients with distal malignant biliary obstruction. In this prospective pilot study, we aimed to evaluate a newly designed ARMS as a reintervention for self-expandable metallic stent (SEMS) occlusion believed to be caused by duodenobiliary reflux.

PATIENTS AND METHODS

Patients with non-resectable distal malignant biliary obstruction were included in whom a prior SEMS was occluded as a result of sludge or food impaction between March 2010 and January 2012 at two Japanese tertiary referral centers. The occluded SEMS were endoscopically removed, if possible, and subsequently replaced by a newly designed ARMS. We evaluated the technical success rate and complications of ARMS and compared the time to occlusion of ARMS with that of prior SEMS.

RESULTS

A total of 13 patients were included. ARMS was successfully placed in all patients in a single procedure. No procedure-related complications were identified. ARMS occlusion occurred in two patients (15%), the causes of which were sludge in one patient and unknown in the other. ARMS migration occurred in four patients (31%). ARMS patency time was significantly longer than that of prior SEMS (median, not available vs 58 days; P = 0.039).

CONCLUSIONS

This newly designed ARMS is a technically feasible, safe, and effective reintervention for SEMS occlusion as a result of sludge or food impaction. An anti-migration mechanism to improve the outcomes of ARMS should be considered.

A novel, fully covered laser-cut nitinol stent with antimigration properties for nonresectable distal malignant biliary obstruction: a multicenter feasibility study

BACKGROUND/AIMS

Stent migration occurs frequently, but the prevention of complications resulting from covered self-expandable metal stents (C-SEMSs) remains unresolved. We prospectively assessed a newly developed C-SEMS, a modified covered Zeo stent (m-CZS), in terms of its antimigration effect.

METHODS

Between February 2010 and January 2011, an m-CZS was inserted into 42 patients (31 initial drainage cases and 11 reintervention cases) at a tertiary referral center and three affiliated hospitals. The laser-cut stent was flared for 1.5 cm at both ends, with a 1 cm raised bank located 1 cm in from each flared end. The main outcome of this study was the rate of stent migration, and secondary outcomes were the rate of recurrent biliary obstruction (RBO), the time to RBO, the frequencies of complications, and overall survival.

RESULTS

Of the 31 patients with initial drainage, stent migration occurred in four (12.9%, 95% confidence interval, 5.1% to 29.0%), with a mean time of 131 days. RBO occurred in 18 (58%), with a median time to RBO of 107 days. Following previous C-SEMS migration, seven of 10 patients (70%) did not experience m-CZS migration until death.

CONCLUSIONS

m-CZSs with antimigration properties effectively, although not completely, prevented stent migration after stent insertion.

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

OBJECTIVES

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

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.

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 systematic review and meta-analysis of randomized trials and prospective studies comparing covered and bare self-expandable metal stents for the treatment of malignant obstruction in the digestive tract

BACKGROUND

Self-expandable metal stents (SEMS) are widely used for the palliative treatment of malignant gastrointestinal obstruction. Our aim was to evaluate the evidence comparing covered and bare SEMS in the digestive tract using meta-analytical techniques.

METHODS

A literature search was performed using PubMed, Cochrane Library, and Embase databases for comparative studies assessing the two types of stents. The primary outcomes of interest were stent patency and patient survival; second outcomes included technical success, clinical success, tumor ingrowth, tumor overgrowth, and stent migration. A random-effects model was conducted. Pooled analysis was done separately based on the different segments of the digestive tract.

RESULTS

Eleven studies (8 randomized controlled trials and 3 prospective cohort studies) including a total of 1376 patients were identified. Covered SEMS were equivalent to bare SEMS in terms of technical success, clinical success, stent patency (gastroduodenal obstruction: HR =0.87, 95% CI 0.53-1.42; colorectal obstruction: HR =0.89, 95% CI 0.18-4.45; biliary obstruction: HR =0.73, 95% CI 0.41-1.32) and survival rates (esophageal obstruction: HR =1.80, 95% CI 0.73-4.44; gastroduodenal obstruction: HR =0.83, 95% CI 0.55-1.26; biliary obstruction: HR =0.99, 95% CI 0.77-1.28), although bare stents were more prone to tumor ingrowth (esophageal obstruction: RR =0.10, 95% CI 0.01-0.77; gastroduodenal obstruction: RR =0.12, 95% CI 0.03-0.55; colorectal obstruction: RR =0.21, 95% CI 0.06-0.70; biliary obstruction: RR =0.21, 95% CI 0.06-0.69), whereas covered stents had the higher risk of stent migration (gastroduodenal obstruction: RR =5.01, 95% CI 1.53-16.43; colorectal obstruction: RR =11.70, 95% CI 2.84-48.27; biliary obstruction: RR =8.11, 95% CI 1.47-44.76) and tumor overgrowth (biliary obstruction: RR =2.03, 95% CI 1.08-3.78).

CONCLUSION

Both covered and bare SEMS are comparable in efficacy for the palliative treatment of malignant obstruction in the digestive tract. Each type of the stents has its own merit and demerit relatively.

Role of intervention for biliary and gastric/intestinal obstruction in gastric cancer with peritoneal metastasis

BACKGROUND AND AIM

Gastrointestinal (GI) luminal obstruction or malignant biliary obstruction (MBO) is not a rare condition in gastric cancer patients with peritoneal metastasis. The role of endoscopic or percutaneous interventions is not fully elucidated in this setting.

METHODS

A total of 123 patients with unresectable or recurrent gastric adenocarcinoma with peritoneal metastasis receiving intravenous and intraperitoneal paclitaxel combined with S-1 were retrospectively studied. Safety and efficacy of interventions for GI luminal obstruction and MBO were evaluated.

RESULTS

A total of 27 patients (22%) underwent GI luminal and/or biliary interventions; GI luminal alone in 10, biliary alone in 10 and both in seven, with a technical success rate of 100%. Clinical success rate was 65% in self-expandable metallic stents (SEMS) placement for GI luminal obstruction. Eastern Cooperative Oncology Group (ECOG) performance status (PS) was prognostic of clinical success in GI luminal stenting (100% in PS of 1 vs 14% in PS of 2-3, P < 0.001). Biliary drainage (endoscopic SEMS placement in four and percutaneous transhepatic biliary drainage in 12) relieved obstructive jaundice in 94%. Six complications were observed: four after GI luminal stenting (two occlusion and one aspiration pneumonia) and two after biliary stenting (one cholangitis and one cholecystitis). Median survival after the initial intervention was 5.7 months. PS at interventions was prognostic of survival after interventions (12.3 months in PS of 1 vs 2.2 months in PS of 2 or 3, P < 0.001).

CONCLUSION

Endoscopic or percutaneous interventions for GI luminal obstruction or MBO were feasible and effective in gastric cancer patients with peritoneal dissemination receiving combination chemotherapy.

One- and two-step self-expandable metal stent placement for distal malignant biliary obstruction: a propensity analysis

BACKGROUND

Although self-expandable metal stents (SEMS) are widely used for distal malignant biliary obstruction, one-step SEMS (direct placement without a prior plastic stent) and two-step SEMS (placement at second endoscopic retrograde cholangiopancreatography [ERCP] following plastic stent placement) have not been fully compared.

METHODS

In this multicenter retrospective study, patients were included who underwent first-time endoscopic SEMS placement between September 1994 and December 2010. We compared the one-step and two-step strategies using a propensity analysis.

RESULTS

In total, 370 patients were identified and one-step SEMS was performed in 59 patients. After adjustment using propensity scores, the median times to dysfunction were 116 and 219 days, respectively, for one-step and two-step SEMS (P = 0.058). Stent migration was more frequently observed in one-step SEMS as compared with two-step SEMS (25 vs. 11 %, P = 0.031). In one-step SEMS, the number of days of hospitalization associated with first-time SEMS placement was shorter compared with that in two-step SEMS (21 vs. 30 days, P = 0.001), and the total costs of SEMS-related interventions within 6 months were lower (6510 and 8100 USD, P = 0.004). The pathological diagnosis rates for pancreatic and biliary tract cancer at initial ERCP were 52 and 61 %. After failed diagnosis at initial ERCP, pathological diagnosis rates for pancreatic cancer were 32 versus 76 % (P = 0.005) by repeated ERCP versus endoscopic ultrasound (EUS)-guided fine-needle aspiration (FNA).

CONCLUSIONS

One-step SEMS was associated with increased stent migration, despite having potential cost-effectiveness. The additional yield of pathological diagnosis at repeated ERCP was low compared with that yielded by EUS-guided FNA.

Duodenal metal stent placement is a risk factor for biliary metal stent dysfunction: an analysis using a time-dependent covariate

BACKGROUND

Although the combination of biliary and duodenal self-expandable metal stents (SEMS) is useful, the exacerbating effect of duodenal SEMS placement on biliary SEMS has not been documented. We conducted a multicenter retrospective study to evaluate the effect of duodenal SEMS placement on biliary SEMS.

METHODS

Patients who underwent first-time biliary SEMS placement for a distal malignant biliary obstruction between September 1994 and November 2010 were included. Time to dysfunction of biliary SEMS was analyzed to identify risk factors for biliary SEMS dysfunction. Duodenal SEMS placement was analyzed as a time-dependent covariate.

RESULTS

In total, 410 eligible patients were identified. Duodenal SEMS were placed in 33 patients (8 %). The median time to dysfunction of biliary SEMS was 170 days. Male gender (hazard ratio 1.37, 95 % confidence interval 1.03-1.83, P = 0.029) and duodenal SEMS placement (hazard ratio 2.00, 95 % confidence interval 1.16-3.45, P = 0.013) were risk factors in the multivariate Cox model. In patients undergoing duodenal SEMS, biliary SEMS dysfunction was observed in 17 (52 %) with a median time to dysfunction of 64 days after duodenal SEMS placement. As many as 60 % of the patients with biliary SEMS dysfunction after duodenal SEMS placement needed permanent percutaneous transhepatic biliary external drainage.

CONCLUSIONS

Duodenal SEMS placement is a risk factor for biliary SEMS dysfunction. Alternative methods for biliary drainage should be considered for better biliary drainage in patients with a gastric outlet obstruction.

Predictive factors of solid food intake in patients with malignant gastric outlet obstruction receiving self-expandable metallic stents for palliation

AIM

As for self-expandable metallic stents (SEMS) for malignant gastric outlet obstruction (GOO), some predictive factors of stent patency have been reported, although re-canalization of GOO by SEMS does not necessarily lead to favorable food intake. Therefore, we analyzed the predictive factors of oral food intake following SEMS placement.

METHODS

A total of 97 consecutive patients in whom SEMS were placed for malignant GOO in five hospitals were included in this retrospective study. Clinical outcomes and predictive factors influencing solid food intake were analyzed.

RESULTS

The technical and clinical success rates were 97.9% and 87.6%, respectively. The mean gastric outlet obstruction scoring system (GOOSS) improved from 0.39 to 2.24 after SEMS placement (P<0.01). The median eating period was 2.1 months (95% CI, 1.1-3.0 months), and the median survival time was 3.1 months (95% CI, 2.0-4.2 months). A Karnofsky performance status of ≤ 50 (odds ratio, 3.65; 95% CI, 1.17-13.1; P=0.03) and ascites (odds ratio, 3.28; 95% CI, 1.23-9.05; P=0.02) were identified as statistically significant independent poor predictive factors of solid food intake.

CONCLUSION

SEMS is an effective treatment for patients with malignant GOO. Ascites and a poor performance status were poor predictive factors of solid food intake.

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.

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.

Management of malignant gastric outlet obstruction with a modified triple-layer covered metal stent

BACKGROUND

A high incidence of migration with covered metal stents has been reported in malignant gastric outlet obstruction (GOO). A newly modified, partially covered, triple-layer nitinol stent was developed that has a longer uncovered portion (5-15 mm) to prevent stent migration.

OBJECTIVE

To estimate the efficacy and safety of the modified covered, triple-layer metal stent.

DESIGN

Multicenter, prospective cohort study.

SETTING

Three tertiary referral centers.

PATIENTS

Fifty consecutive patients (26 with pancreatic carcinoma, 14 with gastric carcinoma, 9 with cholangiocarcinoma, 1 with a metastatic node) who presented with symptomatic unresectable malignant GOO between April 2007 and March 2010.

INTERVENTIONS

Endoscopic placement of the modified covered, triple-layer metal stent.

MAIN OUTCOME MEASUREMENTS

The primary endpoint was to improve the GOO scoring system (GOOSS) score. Secondary endpoints were success rate, patency, and complications.

RESULTS

The median GOOSS score improved significantly (P < .0001) after stenting (from 0 to 3). The technical and clinical success rates were 100% and 90%, respectively. Stent occlusion by tumor overgrowth or ingrowth at the uncovered portion developed in 5 patients (10%). Asymptomatic stent migration occurred in 3 patients (6%) receiving chemotherapy at 95, 230, and 553 days after stent placement, but these patients tolerated solid food 68, 260, and 142 days after stent migration, respectively. Other complications occurred in 1 patient with insufficient expansion, cholangitis, and pancreatitis. No procedure-related deaths occurred.

LIMITATIONS

A single-arm study in tertiary-care centers.

CONCLUSIONS

The modified covered, triple-layer metal stent was effective and safe for managing malignant GOO and can prevent tumor ingrowth and stent migration. (

CLINICAL TRIAL REGISTRATION NUMBER

UMIN000004566.).

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.

Duodenal invasion is a risk factor for the early dysfunction of biliary metal stents in unresectable pancreatic cancer

BACKGROUND

Although the placement of self-expandable metal stents (SEMSs) has been widely accepted as palliation for distal malignant biliary obstruction, the risk factors for their early dysfunction remain unclear.

OBJECTIVE

To identify risk factors for early (<3 months) SEMS dysfunction in unresectable pancreatic cancer.

DESIGN

A multicenter retrospective study.

SETTING

Five tertiary referral centers.

PATIENTS

Patients were included who underwent first-time SEMS placement for distal malignant biliary obstruction caused by pancreatic cancer between April 1994 and August 2010.

MAIN OUTCOME MEASUREMENTS

Rates and causes of early dysfunction were evaluated, and risk factors were analyzed.

RESULTS

In all, 317 eligible patients were identified. Covered SEMSs were placed in 82% of patients. Duodenal invasion was observed endoscopically in 37%. The median time to dysfunction was 170 days. The rates of all and early SEMS dysfunction were 55% and 31%, respectively. The major causes of SEMS dysfunction were food impaction and nonocclusion cholangitis (21% each) in early dysfunction and sludge (29%) in nonearly dysfunction. The rate of early dysfunction was 42% with duodenal invasion and 24% without duodenal invasion (P = .001). Early dysfunction caused by food impaction was more frequent in patients with duodenal invasion (10% and 4%, P = .053). Duodenal invasion was a risk factor (odds ratio 2.35; 95% CI, 1.43-3.90; P = .001) in a multiple logistic regression model.

LIMITATIONS

A retrospective design.

CONCLUSIONS

Duodenal invasion is a risk factor for early SEMS dysfunction in patients with pancreatic cancer.

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.