Drug-eluting stent in malignant biliary obstruction

Advances in functional coatings on biliary stents

Biliary stenting is an important interventional method for the prevention and treatment of biliary tract diseases. However, complications, such as postoperative biliary infection and restenosis, frequently occur due to the extensive scope of the biliary system and the complex composition of bile. The combination of coating technology and biliary stents is expected to bring new approaches to the solution of these problems. The cutting-edge advance on functional coatings on biliary stents is reviewed from seven perspectives: anticorrosion, -bacterial, -tumor, stone-dissolving, X-ray visibility, antistent migration and functional composite coatings. The development trend is also discussed. Overall, the performance of the numerous functional coatings for various purposes is generally up to expectations, but the balance between the medications' effectiveness and their safety needs to be further adjusted. Many contemporary investigations have advanced to the level of animal experiments, offering crucial fundamental assurance for broader human studies. The combination of biliary stents and functional coatings is an innovative idea with great potential for future development.

Ink-jet 3D printing as a strategy for developing bespoke non-eluting biofilm resistant medical devices

Chronic infection as a result of bacterial biofilm formation on implanted medical devices is a major global healthcare problem requiring new biocompatible, biofilm-resistant materials. Here we demonstrate how bespoke devices can be manufactured through ink-jet-based 3D printing using bacterial biofilm inhibiting formulations without the need for eluting antibiotics or coatings. Candidate monomers were formulated and their processability and reliability demonstrated. Formulations for in vivo evaluation of the 3D printed structures were selected on the basis of their in vitro bacterial biofilm inhibitory properties and lack of mammalian cell cytotoxicity. In vivo in a mouse implant infection model, Pseudomonas aeruginosa biofilm formation on poly-TCDMDA was reduced by ~99% when compared with medical grade silicone. Whole mouse bioluminescence imaging and tissue immunohistochemistry revealed the ability of the printed device to modulate host immune responses as well as preventing biofilm formation on the device and infection of the surrounding tissues. Since 3D printing can be used to manufacture devices for both prototyping and clinical use, the versatility of ink-jet based 3D-printing to create personalised functional medical devices is demonstrated by the biofilm resistance of both a finger joint prosthetic and a prostatic stent printed in poly-TCDMDA towards P. aeruginosa and Staphylococcus aureus.

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.

Metallic Stent Mesh Coated with Silver Nanoparticles Suppresses Stent-Induced Tissue Hyperplasia and Biliary Sludge in the Rabbit Extrahepatic Bile Duct

Recent therapeutic strategies to suppress restenosis after biliary stent placement are insufficient. Here, we demonstrate the usefulness of a self-expandable metal stent (SEMS), a stent mesh coated with silver nanoparticles (AgNPs), for suppression of both stent-induced tissue hyperplasia and biliary sludge formation in the rabbit bile duct. The AgNP-coated SEMSs were prepared using a simple bio-inspired surface modification process. Then, the prepared SEMSs were successfully placed in 22 of 24 rabbits. Sludge formation in the AgNP-coated SEMS groups was significantly decreased compared to the control group on gross findings. Cholangiographic and histologic examinations demonstrated significantly decreased tissue hyperplasia in the AgNP-coated SEMS groups compared with the control group (p < 0.05 for all). There were no differences between the AgNP-coated SEMS groups (p > 0.05 for all). However, in the group coated with the greatest concentration of AgNPs (Group D), submucosal fibrosis was thicker than in the other AgNP-coated groups (p < 0.05 for all). The AgNP-coated metallic stent mesh significantly suppressed stent-induced tissue hyperplasia and biliary sludge formation in the rabbit bile duct. Taken together, the AgNP coating strategy developed in this study could be widely utilized in non-vascular medical devices for anti-bacterial and anti-inflammatory responses.

Antibiotics in 3D-printed implants, instruments and materials: benefits, challenges and future directions

3D printing is an additive manufacturing technology, which permits innovative approaches for incorporating antibiotics into 3D printed constructs. Antibiotic-incorporating applications in medicine have included medical implants, prostheses, along with procedural and surgical instruments. 3D-printed antibiotic-impregnated devices offer the advantages of increased surface area for drug distribution, sequential layers of antibiotics produced through layer-by-layer fabrication, and the ability to rapidly fabricate constructs based on patient-specific anatomies. To date, fused deposition modeling has been the main 3D printing method used to incorporate antibiotics, although inkjet and stereolithography techniques have also been described. This review offers a state-of-the-art summary of studies that incorporate antibiotics into 3D-printed constructs and summarizes the rationale, challenges, and future directions for the potential use of this technology in patient care.

Piperlongumine-Eluting Gastrointestinal Stent Using Reactive Oxygen Species-Sensitive Nanofiber Mats for Inhibition of Cholangiocarcinoma Cells

BACKGROUND

The aim of this study is to fabricate drug-eluting gastrointestinal (GI) stent using reactive oxygen species (ROS)-sensitive nanofiber mats for treatment of cholangiocarcinoma (CCA) cell. A ROS-producing agent, piperlongumine (PL)-incorporated nanofiber mats were investigated for drug-eluting stent (DES) application.

METHODS

Selenocystamine-conjugated methoxy poly(ethylene glycol) (MePEG) was conjugated with poly(L-lactide) (PLA) to produce block copolymer (LEse block copolymer). Various ratios of poly(ε-caprolactone) (PCL) and LEse block copolymer were dissolved in organic solvent with PL, and then nanofiber mats were fabricated by electro-spinning techniques.

RESULTS

The higher amount of LEse in the blend of PCL/LEse resulted in the formation of granules while PCL alone showed fine nanofiber structure. Nanofiber mats composed of PCL/LEse polymer blend showed ROS-sensitive drug release, i.e., PL release rate from nanofiber mats was accelerated in the presence of hydrogen peroxide (H₂O₂) while nanofiber mats of PCL alone have small changes in drug release rate, indicating that PL-incorporated nanofiber membranes have ROS responsiveness. PL itself and PL released from nanofiber mats showed almost similar anticancer activity against various CCA cells. Furthermore, PL released from nanofiber mats properly produced ROS generation and induced apoptosis of CCA cells as well as PL itself. In HuCC-T1 cell-bearing mice, PL-incorporated nanofiber mats showed improvement in anticancer activity.

CONCLUSION

PL-incorporated ROS-sensitive nanofiber mats were coated onto GI stent and showed improved anticancer activity with ROS responsiveness. We suggested PL-incorporated ROS-sensitive nanofiber mats as a promising candidate for local treatment of CCA cells.

Construction of multilayer films with bactericidal and long-term antitumor drug release properties as a non-vascular stent coating for therapy in obstruction

An antibacterial and antitumor coating for non-vascular stent was constructed via the layer-by-layer electrostatic self-assembly method.

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.

Stent containing CD44-targeting polymeric prodrug nanoparticles that release paclitaxel and gemcitabine in a time interval-controlled manner for synergistic human biliary cancer therapy

The use of drug-eluting stents (DESs) is a promising strategy for non-vascular diseases, especially human biliary cancer. However, the implementation of DESs suffers from two major obstacles: the side effects of drugs and the difficulty of controlling the drug release. These problems can be overcome if the stent elutes targeting nanoparticles that release drugs at time intervals that are dictated by the mechanisms of those drugs. We designed temporally controlled polymeric multi-prodrug nanoparticles (TCMPNs) that can be eluted from stents comprising polyurethane (PU) nanofiber as a polymeric matrix and paclitaxel (PTX)-loaded, CD44-targeting, hyaluronic acid-conjugated poly(lactic-co-glycolic acid) and gemcitabine (GEM) (P-H-G). TCMPNs enable two different types of drugs to be released temporally; PTX is released first owing to the collapse of the structure in the endosomes, and GEM, which induces synergistic anticancer activities, is hydrolyzed from P-H-G later in response to low pH. Embedded in the PU nanofiber, the TCMPNs demonstrate low initial burst behavior and sustainable release of the prodrug in vitro. Furthermore, TCMPN-eluting stents (TESs) exhibit continuous synergistic efficacy as available targeted cellular uptake prodrug delivery systems in tumor-bearing mice. These results demonstrate that this technology will open up cancer therapy by combining localized delivery and functional multi-drug-loaded nanoparticles.

Comparative Study of Percutaneous Transhepatic Biliary Stent Placement with or without Iodine-125 Seeds for Treating Patients with Malignant Biliary Obstruction

PURPOSE

To prospectively evaluate safety and efficacy of biliary stent placement with iodine-125 (¹²⁵I) seeds in patients with malignant obstructive jaundice (MOJ).

MATERIALS AND METHODS

From July 2011 to June 2014, 55 patients were enrolled (group A, 11 men and 17 women, mean age 70.93 y ± 8.58; group B, 14 men and 13 women, mean age 70.26 y ± 9.71). All patients were randomly assigned to placement of a biliary stent with ¹²⁵I seeds (group A) or biliary stent only (group B). After stent placement, outcomes were measured regarding relief of MOJ. Clinical success rate, survival time, and safety were recorded. P < .05 was considered to indicate significant difference.

RESULTS

Stents were successfully placed in all 55 patients. MOJ was relieved in all patients, and there were no significant differences in complications related to stent insertion between the 2 groups. Mean and median stent patency were 191 days ± 19.8 (95% confidence interval [CI], 152-230 d) and 179 days ± 191.4 (95% CI, 87-267 d) in group A and 88.3 days ± 16.3 (95% CI, 61-114 d) and 77 days ± 88.2 (95% CI, 65-86 d) in group B (P < .001, log-rank test). Mean and median survival time were 222.6 days ± 21.0 (95% CI, 181-263 d) and 241 days ± 18.2 (95% CI, 179-270 d) in group A and 139.1 days ± 14.5 (95% CI, 110-167 d) and 142 days ± 16.3 (95% CI, 83-177 d) in group B (P < .001, log-rank test).

CONCLUSIONS

¹²⁵I seeds combined with biliary stent placement could significantly improve stent patency. The procedure seems to be safe and to extend survival compared with self-expandable biliary stent placement.

A pilot study of intraluminal brachytherapy using 125I seed strand for locally advanced pancreatic ductal adenocarcinoma with obstructive jaundice

PURPOSE

To investigate the safety and feasibility of intraluminal brachytherapy using 125I seed strand for locally advanced pancreatic ductal adenocarcinoma with obstructive jaundice.

METHODS AND MATERIALS

From January 2010 to February 2015, 18 consecutive patients diagnosed with locally advanced, nonmetastatic, inoperable pancreatic ductal adenocarcinoma with obstructive jaundice were enrolled and underwent intraluminal brachytherapy using 125I seed strand. Dose calculation was performed using a software. The procedure-related and radiation complications were assessed. Obstruction-free survival and overall survival were calculated using the Kaplan-Meier method.

RESULTS

The technique successful rate of 125I seed strand implantation was 100%. Successful bile drainage was achieved in all patients. The estimated mean accumulating dose (R = 5 mm, z = 0, 240 days) was 167.2 Gy, from 164.19 to 170.05 Gy. Two patients had adverse event of Grade 3, one of Grade 4. Stent dysfunction occurred in 1/18 (5.6%) patients. The mean and median obstruction-free survival time were 10.61 months (95% confidence interval [CI]: 7.04, 14.18) and 7.26 months (95% CI: 2.14, 12.38). The mean and median overall survival time were 11.91 months (95% CI: 7.39, 16.43) and 7.26 months (95% CI: 2.14, 12.38).

CONCLUSIONS

Intraluminal brachytherapy using 125I seed strand may be consider as a safe treatment option for the therapy of locally advanced pancreatic duct adenocarcinoma complicated by obstructive jaundice with acceptable complication rates.

Recent Advances in Gastrointestinal Stent Development

Endoscopic stenting is increasingly being used in the management of gastrointestinal luminal obstruction, and has become the current treatment of choice for the palliation of blockage caused by malignant or benign growths. A variety of stents have been developed to enhance the efficacy of the procedure, and improvements are ongoing. In this article, we review the history of, and recent advances in, gastrointestinal stenting. We describe the rationale behind the design as well as the resulting outcome for each stent type.

Recent Advances in Gastrointestinal Stent Development

Endoscopic stenting is increasingly being used in the management of gastrointestinal luminal obstruction, and has become the current treatment of choice for the palliation of blockage caused by malignant or benign growths. A variety of stents have been developed to enhance the efficacy of the procedure, and improvements are ongoing. In this article, we review the history of, and recent advances in, gastrointestinal stenting. We describe the rationale behind the design as well as the resulting outcome for each stent type.

Molecular mechanism of local drug delivery with Paclitaxel-eluting membranes in biliary and pancreatic cancer: new application for an old drug

Implantation of self-expanding metal stents (SEMS) is palliation for patients suffering from inoperable malignant obstructions associated with biliary and pancreatic cancers. Chemotherapeutic agent-eluting stents have been developed because SEMS are susceptible to occlusion by tumor in-growth. We reported recently that paclitaxel-eluting SEMS provide enhanced local drug delivery in an animal model. However, little is known about the molecular mechanisms by which paclitaxel-eluting stents attenuate tumor growth. We investigated the signal transduction pathways underlying the antiproliferative effects of a paclitaxel-eluting membrane (PEM) implanted in pancreatic/cholangiocarcinoma tumor bearing nude mice. Molecular and cellular alterations were analyzed in the PEM-implanted pancreatic/cholangiocarcinoma xenograft tumors by Western blot, immunoprecipitation, and immunofluorescence. The quantities of paclitaxel released into the tumor and plasma were determined by liquid chromatography-tandem mass spectroscopy. Paclitaxel from the PEM and its diffusion into the tumor inhibited angiogenesis, which involved suppression of mammalian target of rapamycin (mTOR) through regulation of hypoxia inducible factor (HIF-1) and increased apoptosis. Moreover, implantation of the PEM inhibited tumor-stromal interaction-related expression of proteins such as CD44, SPARC, matrix metalloproteinase-2, and vimentin. Local delivery of paclitaxel from a PEM inhibited growth of pancreatic/cholangiocarcinoma tumors in nude mice by suppressing angiogenesis via the mTOR and inducing apoptosis signal pathway.

Photochemical tissue penetration via photosensitizer for effective drug penetration in a non-vascular tumor

To improve the tissue penetration efficiency (PE%) of hydrophilic-drugs in non-vascular drug eluting stents (DES), we designed photochemical tissue penetration (PTP) invested DES (PTP-DES). The PTP technology was applied to the stent as a covering membrane to generate singlet oxygen. Singlet oxygen damages the epithelial layer, so the PE% of released drugs could be improved. To prepare the PTP-DES membrane, chlorin e6 (Ce6, photosensitizer) was incorporated in a gemcitabine (GEM) eluting polyurethane (PU) membrane (Ce6-GEM-PU). Ce6-GEM-PU has smooth surface that is ∼40 μm thick. The photoactivity of Ce6 was maintained for 2 weeks (in vitro GEM releasing period). In a separate cell culture system, both 1.5 folds higher PE% and an improved tumor cell growth inhibition effect were shown after light exposure. Additionally, in tissue penetration experimental system, 2 folds increased in the PE% of GEM was induced by laser exposure at 80 J/cm2. Additionally, improved PE% of hydrophilic molecules (Fluorescein and GEM) was confirmed in colon tumor bearing mice. Consequentially, tumor growth, when implanted with Ce6-GEM-PU, was effectively inhibited without significant side effects. Based on these results, we believe that the PTP-DES system has great potential for improving the therapeutic effect of conventional DES.

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.

Polyurethane membrane with porous surface for controlled drug release in drug eluting stent

Background

Membrane covered drug eluting stents (DES) were prepared to prevent tumor ingrowth and to control drug release. Polyurethane (PU) is commonly used for DES coating material because of high tensile strength. The release of paclitaxel (PTX) may increase from porous PU membrane.

Results

Polyethylene glycol (PEG) was incorporated into PU membranes to form porous structure and control the release of hydrophobic anti-cancer drug such as PTX. The bare metal stents were coated with PEG incorporated PU and then, PEG was washed out to form porous structure. The crystallization of PTX was inhibited in porous PU membranes and the release of PTX from porous PU membranes was approximately 8.6% more extended over 19 days.

Conclusions

The enhanced release of PTX from porous PU membranes may increase the patency for the DES covering materials.

Prototype of biliary drug-eluting stent with photodynamic and chemotherapy using electrospinning

Background

The combination of biliary stent with photodynamic and chemotherapy seemed to be a beneficial palliative treatment of unresectable cholangiocarcinoma. However, by intravenous delivery to the target tumor the distribution of the drug had its limitations and caused serious side effect on non-target organs. Therefore, in this study, we are going to develop a localized eluting stent, named PDT-chemo stent, covered with gemcitabine (GEM) and hematoporphyrin (HP).

Methods

The prototype of PDT-chemo stent was made through electrospinning and electrospraying dual-processes with an electrical charge to cover the stent with a drug-storing membrane from polymer liquid. The design of prototype used PU as the material of the backing layer, and PCL/PEG blends in different molar ratio of 9:1 and of 1:4 were used in two drug-storing layers with GEM and HP loaded respectively.

Results

The optical microscopy revealed that the backing layer was formed in fine fibers from electrospinning, while drug-storing layers, attributed to the droplets from electrospraying process. The covered membrane, the morphology of which was observed by scanning electron microscopy (SEM), covered the stent surface homogeneously without crack appearances. The GEM had almost 100% of electrosprayed efficiency than 70% HP loaded on the covered membrane due to the different solubility of drug in PEG/PCL blends. Drug release study confirmed the two-phased drug release pattern by regulating in different molar ratio of PEG/PCL blends polymer.

Conclusions

The result proves that the PDT-chemo stent is composed of a first burst-releasing phase from HP and a later slow-releasing phase from GEM eluting. This two-phase of drug eluting stent may provide a new prospect of localized and controlled release treatment for cholangiocarcinoma disease.

Effect of external beam radiotherapy on patency of uncovered metallic stents in patients with inoperable bile duct cancer

BACKGROUND

Although biliary decompression with metallic stenting is the preferred treatment for inoperable bile duct cancer (BDC), maintenance of patency is still unsatisfactory. We tried to assess the effectiveness and safety of external beam radiotherapy (EBRT) for prolonging stent patency in patients having uncovered metallic stents.

METHOD

We retrospectively reviewed 50 patients who received endoscopic stenting, of whom 18 received EBRT (RT group) and 32 did not (non-RT group).

RESULTS

No difference was found in baseline characteristics between the two groups. Although stent patency was longer in the RT group than that in the non-RT group (140.7+/-51.3 vs 136.4+/-34.9 days, P=0.94), the difference was not statistically significant. There were a lower rate of stent occlusion (27.8% vs 50.0% of patients, P=0.12) and a longer overall survival (420.1+/-73.2 vs 269.1+/-41.7 days, P=0.11) in the RT group than in the non-RT group, and the difference again was not statistically significant. The development of adverse reactions did not differ (55.6% vs 53.1% of patients, P=0.91). There was no serious adverse reaction in both groups (P=0.99).

CONCLUSIONS

EBRT did not significantly improve stent patency in patients with inoperable BDC having uncovered metallic stents. However, EBRT was safe. Future trials with refined protocols for better efficacy are expected.

Biliary stenting for cholangiocarcinoma: An update

Cholangiocarcinoma (bile duct cancer) is the most common malignant tumor of the biliary tree. This devastating malignancy presents late, and is notoriously difficult to diagnose, thus resulting a high mortality. The majority of cholangiocarcinoma patients present with an unresectable disease, and survive less than 12 mo following diagnosis. Biliary stent placement is an effective palliative therapy for malignant biliary obstruction, which can significantly improve the quality of life, and extend the survival time of patients. Different biliary stent placement methods would closely affect the prognosis of patients. The purpose of this article is to review the treatment efficacy, insertion paths and types of biliary stents. This paper also covers emerging biliary stents including drug stents, and biliary stent combination local therapy.

Functional self-expandable metal stents in biliary obstruction

Biliary stents are widely used not only for palliative treatment of malignant biliary obstruction but also for benign biliary diseases. Each plastic stent or self-expandable metal stent (SEMS) has its own advantages, and a proper stent should be selected carefully for individual condition. To compensate and overcome several drawbacks of SEMS, functional self-expandable metal stent (FSEMS) has been developed with much progress so far. This article looks into the outcomes and defects of each stent type for benign biliary stricture and describes newly introduced FSEMSs according to their functional categories.

Percutaneous trans-hepatic bilateral biliary stenting in Bismuth IV malignant obstruction

AIM

To investigate the clinical efficiency of percutaneous trans-hepatic bilateral biliary metallic stenting for the management of Bismuth IV malignant obstructive disease.

METHODS

Our hospital's database was searched for all patients suffering from the inoperable malignant biliary obstruction Bismuth IV, and treated with percutaneous bilateral trans-hepatic placement of self-expandable nitinol stents. The indication for percutaneous stenting was an inoperable, malignant, symptomatic, biliary obstruction. An un-correctable coagulation disorder was the only absolute contra-indication for treatment. Bismuth grading was performed using magnetic resonance cholangiopancreatography. Computed tomography evaluation of the lesion and the dilatation status of the biliary tree was always performed prior to the procedure. All procedures were performed under conscious sedation. A single trans-hepatic track technique was preferred (T-configuration stenting) and a second, contra-lateral trans-hepatic track (Y-configuration stenting) was used only in cases of inability to access the contra-lateral lobe using a single track technique. The study's primary endpoints were clinical success, defined as a decrease in bilirubin levels within 10 d and patient survival rates. Secondary endpoints included peri-procedural complications, primary and secondary patency rates.

RESULTS

A total of 35 patients (18 female, 51.4%) with a mean age 69 ± 13 years (range 33-88) were included in the study. The procedures were performed between March 2000 and June 2008 and mean time follow-up was 13.5 ± 22.0 mo (range 0-96). The underlying malignant disease was cholangiocarcinoma (n = 10), hepatocellular carcinoma (n = 9), pancreatic carcinoma (n = 5), gastric cancer (n = 2), bile duct tumor (n = 2), colorectal cancer (n = 2), gallbladder carcinoma (n = 2), lung cancer (n = 1), breast cancer (n = 1) or non-Hodgkin lymphoma (n = 1). In all cases, various self-expandable bare metal stents with diameters ranging from 7 to 10 mm were used. Stents were placed in Y-configuration in 24/35 cases (68.6%) using two stents in 12/24 patients and three stents in 12/24 cases (50%). A T-configuration stent placement was performed in 11/35 patients (31.4%), using two stents in 4/11 cases (36.4%) and three stents in 7/11 cases (63.6%). Follow-up was available in all patients (35/35). Patient survival ranged from 0 to 1763 d and the mean survival time was 168 d. Clinical success rate was 77.1% (27/35 cases), and peri-procedural mortality rate was 5.7% (2/35 patients). Biliary re-obstruction due to stent occlusion occurred in 25.7% of the cases (9/35 patients), while in 7/11 (63.6%) one additional percutaneous re-intervention due to stent occlusion resulting in clinical relapse of symptomatology was successfully performed. In the remaining 4/11 patients (36.4%) more than 1 additional reintervention was performed. The median decrease of total serum bilirubin was 60.5% and occurred in 81.8% of the cases (27/33 patients). The median primary and secondary patency was 105 (range 0-719) and 181 d (range 5-1763), respectively. According to the Kaplan-Meyer survival analysis, the estimated survival rate was 73.5%, 47.1% and 26.1% at 1, 6 and 12 mo respectively, while the 8-year survival rate was 4.9%. Major and minor complication rates were 5.7% (2/35 patients) and 17.1% (6/35 patients), respectively.

CONCLUSION

Percutaneous bilateral biliary stenting is a safe and clinically effective palliative approach in patients suffering from Bismuth IV malignant obstruction.

Efficacy of a metallic stent covered with a paclitaxel-incorporated membrane versus a covered metal stent for malignant biliary obstruction: a prospective comparative study

BACKGROUND

The placement of a self-expandable metallic stent (SEMS) is a widely used nonsurgical treatment method in patients with unresectable malignant biliary obstructions but SEMS is susceptible to occlusion by tumor ingrowth or overgrowth.

AIM

The efficacy and safety of a metallic stent covered with a paclitaxel-incorporated membrane (MSCPM) in which paclitaxel provided an antitumoral effect was compared prospectively with those of a covered metal stent (CMS) in patients with malignant biliary obstructions.

METHODS

Patients with unresectable distal malignant biliary obstructions (n = 106) were prospectively enrolled in this study at multiple treatment centers. A MSCPM was inserted endoscopically in 60 patients, and a CMS was inserted in 46 patients. Patients underwent systemic chemotherapy regimens alternatively according to disease characteristics.

RESULTS

The two groups did not differ significantly in mean age, male to female ratio, or mean follow-up period. Stent occlusion due to tumor ingrowth occurred in 12 patients who received MSCPMs and in eight patients who received CMSs. Stent patency and survival time did not differ significantly between the two groups (p = 0.116, 0.981). Chemotherapy had no influence on stent patency, but gemcitabine-based chemotherapy was a significant prognostic factor for survival time (p = 0.012). Complications, including cholangitis and pancreatitis, were found to be acceptable in both groups.

CONCLUSIONS

Although the use of a MSCPM produced no significant differences in stent patency or patient survival in patients with malignant biliary obstructions compared with the use of a CMS, this study demonstrated that MSCPM can be used safely in humans.

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

BACKGROUND AND AIM

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

METHODS

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

RESULTS

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

CONCLUSION

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

Paclitaxel-eluting covered metal stents versus covered metal stents for distal malignant biliary obstruction: a prospective comparative pilot study

BACKGROUND

In unresectable malignant biliary obstruction, stent insertion can be the treatment of choice. However, metal stents are susceptible to occlusion by tumor ingrowth or overgrowth. The recently introduced paclitaxel-eluting covered metal stents (PECMSs) may prevent occlusion from tumor ingrowth by the antitumor effect of paclitaxel.

OBJECTIVE

Our goal was to compare the efficacy and complication rates of PECMSs and the control covered metal stents (CCMSs) in patients with malignant biliary obstruction.

DESIGN

Prospective, randomized pilot study.

SETTING

Single tertiary referral center.

PATIENTS

From November 2006 to June 2008, 52 patients with unresectable distal malignant biliary obstruction were enrolled. A PECMS was inserted in 26 patients and a CCMS in 26 patients. Of these patients, 2 patients in the PECMS group and 1 patient in the CCMS group were excluded. Finally 49 patients (24 patients in the PECMS group and 25 patients in the CCMS group) were included in the analysis.

INTERVENTIONS

PECMSs and CCMSs were inserted by using the standard ERCP technique.

RESULTS

The mean follow-up period was 194.0 ± 144.2 days in the PECMS group and 238.8 ± 147.4 days in the CCMS group (P = .287). The stent patency duration and survival time were not significantly different between the 2 groups (P = .307 and P = .596, respectively). Stent occlusion caused by tumor ingrowth occurred in 5 patients in the PECMS group. In the CCMS group, stent occlusion caused by tumor ingrowth (n = 4) or distal stent migration (n = 4) occurred in 8 patients. In the PECMS group, 3 cases of transient cholangitis-like symptoms without stent occlusion and 1 case of pancreatitis occurred after stent insertion. One patient in the CCMS group experienced pancreatitis.

LIMITATIONS

This study was a pilot study in which no power calculation was done. It was performed at a single center and was performed in a nonblinded fashion.

CONCLUSIONS

PECMSs may be safe with acceptable complication rates. There were no significant differences in the duration of stent patency and patient survival time between PECMSs and CCMSs in patients with distal malignant biliary obstruction. However, a larger study powered to detect differences must be done to conclude that there is any benefit of PECMSs.