The role of ciprofloxacin in prolonging polyethylene biliary stent patency: a multicenter, double-blinded effectiveness study

Feasibility of in vivo swine models using guide wire-assisted intraductal radiofrequency ablation for benign biliary stricture

Several in vivo swine models of benign biliary stenosis (BBS) have been recently reported for preclinical studies of novel endoscopic techniques and devices. The aim of this study was to evaluate the efficacy and feasibility of large animal models of BBS by using intraductal radiofrequency ablation (RFA) assisted by guide wire. Six in vivo swine models were made by using an intraductal RFA for cauterization at 10 W, 80 °C, 90 s in the common bile duct (CBD). Endoscopic retrograde cholangiopancreatography (ERCP) was performed with cholangiography and histologic evaluation was done for the common bile duct. Blood tests were examined before, after, and at the final follow-up. Guide wire assisted RFA electrode produced BBS in all (6/6, 100%) animal models without severe complications. Fluoroscopy findings at 2 weeks after intraductal RFA in every model revealed BBS in the common bile duct. In histologic evaluations, fibrosis and chronic inflammatory changes were noted. After the procedure, ALP, GGT, and CRP were elevated and decreased after an appropriate drain. A swine model of BBS is developed by inducing intraductal thermal injury using intraductal RFA assisted by guide wire. This novel technique for inducing BBS in swine is effective and feasible.

A fully covered self-expandable metallic stent coated with poly (2-methoxyethyl acrylate) and its derivative: In vitro evaluation of early-stage biliary sludge formation inhibition

The adhesion and deformation behavior of proteins at the inner surface of fully covered, self-expandable metallic stents coated with biocompatible polymers, poly(2-methoxyethyl acrylate) (PMEA) and poly(3-methoxypropyl acrylate) (PMC3A), were analyzed. Model bile solution, proteins, and bacteria were used to unravel the inhibitory ability of the polymer coatings. Adsorbance of proteins and adherence of bacteria were both strongly inhibited by the polymer coatings. Circulation tests were performed under clinical conditions using human bile from patients. Adsorption/deformation of proteins and early-stage sludge formation were inhibited on stent surfaces coated with PMEA derivatives. The present study revealed that early-stage biliary sludge formation on PMEA- and PMC3A-coated stents was suppressed due to the strong resistance of the polymers to protein adsorption/deformation, brought about by intermediate water in hydrated polymer coatings, which is not present in conventional coating materials, such as silicone and polyurethane.

Plastic vs. Self-Expandable Metal Stents for Palliation in Malignant Biliary Obstruction: A Series of Meta-Analyses

OBJECTIVES

Self-expandable metal stents (SEMS) are thought to have an advantage over plastic stents in achieving biliary drainage.

METHODS

We performed a systematic search of MEDLINE, EMBASE, Scopus, CENTRAL, and ISI Web of knowledge databases, from January 1980 to September 2015, for randomized-controlled trials (RCTs) comparing SEMS vs. plastic stents in the palliation of malignant biliary obstruction. Primary outcomes were durations of stent patency, patient survival, and 30-day mortality. Numerous secondary outcomes were assessed, and extensive sensitivity and subgroup analyses were performed.

RESULTS

In all, 20 RCTs totaling 1,713 patients yielded a weighted mean difference (WMD) in time to stent patency (4 studies) of 4.45 months (95% confidence interval (CI), 0.31, 8.59; GRADE=moderate) favoring SEMS. There were no differences in overall patient survival (5 studies) WMD=0.67 months (95% CI, -0.66, 1.99; GRADE=moderate), or 30-day mortality (8 studies) odds ratio (OR)=0.80 (95% CI, 0.52, 1.24; GRADE=moderate) but there was a higher symptom-free survival at 6 months (4 studies) OR=5.96 (95% CI, 1.71, 20.81; GRADE=moderate). SEMS use resulted in lower rates of late complications (11 studies) OR=0.43 (95% CI, 0.26, 0.71; GRADE=moderate), sepsis or cholangitis (14 studies) OR=0.53 (95% CI, 0.37, 0.77; GRADE=high), blocking from sludge (8 studies) OR=0.11(95% CI, 0.07, 0.17; GRADE=moderate), and mean number of re-interventions (8 studies) WMD=-0.83 interventions (95% CI, -1.64, -0.02; GRADE=moderate). There was a longer patency of SEMS for those without a prior drainage attempt (2 studies) WMD 7.70 months (95% CI, 7.14, 8.25; GRADE=high). Although a survival advantage was found when an uncovered SEMS was used (3 studies) WMD 1.31 months (95% CI, 0.30, 2.32; GRADE=high), but not partially or fully covered SEMS (2 studies) WMD -0.66 months (95% CI, -1.02, -0.30; GRADE=high) vs. plastic stents, and for SEMS in the setting of pre- or post-procedural antibiotic administration (2 studies) WMD 1.49 months (95% CI, 0.27, 2.70; GRADE=high), and performance of a sphincterotomy (2 studies) WMD 1.63 months (95% CI, 0.42, 2.84; GRADE=high).

CONCLUSIONS

Keeping in mind the noted risk of bias in source data, the use of SEMS compared with plastic stents, in the palliation of patients with malignant biliary obstruction results in longer stent patency, lower complications rates, and fewer re-interventions, whereas exhibiting survival benefits in selected subgroups of patients.

Impact of biliary stent-related events in patients diagnosed with advanced pancreatobiliary tumours receiving palliative chemotherapy

AIM: To determine the impact (morbidity/mortality) of biliary stent-related events (SRE) (cholangitis or stent obstruction) in chemotherapy-treated pancreatico-biliary patients.

METHODS: All consecutive patients with advanced pancreatobiliary cancer and a biliary stent in-situ prior to starting palliative chemotherapy were identified retrospectively from local electronic case-note records (Jan 13 to Jan 15). The primary end-point was SRE rate and the time-to-SRE (defined as time from first stenting before chemotherapy to date of SRE). Progression-free survival and overall survival were measured from the time of starting chemotherapy. Kaplan-Meier, Cox and Fine-Gray regression (univariate and multivariable) analyses were employed, as appropriate. For the analysis of time-to-SRE, death was considered as a competing event.

RESULTS: Ninety-six out of 693 screened patients were eligible; 89% had a metal stent (the remainder were plastic). The median time of follow-up was 9.6 mo (range 2.2 to 26.4). Forty-one patients (43%) developed a SRE during follow-up [cholangitis (39%), stent obstruction (29%), both (32%)]. There were no significant differences in baseline characteristics between the SRE group and no-SRE groups. Recorded SRE-consequences were: none (37%), chemotherapy delay (24%), discontinuation (17%) and death (22%). The median time-to-SRE was 4.4 mo (95%CI: 3.6-5.5). Patients with severe comorbidities (P < 0.001) and patients with ≥ 2 baseline stents/biliary procedures [HR = 2.3 (95%CI: 1.2-4.44), P = 0.010] had a shorter time-to-SRE on multivariable analysis. Stage was an independent prognostic factor for overall survival (P = 0.029) in the multivariable analysis adjusted for primary tumour site, performance status and development of SRE (SRE group vs no-SRE group).

CONCLUSION: SREs are common and impact on patient’s morbidity. Our results highlight the need for prospective studies exploring the role of prophylactic strategies to prevent/delay SREs.

Drainage-related Complications in Percutaneous Transhepatic Biliary Drainage: An Analysis Over 10 Years

BACKGROUND

Procedure-related complications of percutaneous transhepatic biliary drainage (PTBD) have been well documented in the literature. However, relatively restricted data are available concerning drainage-related complication rates in long-term PTBD therapy. The present retrospective study evaluated the extent and the nature of drainage complications during PTBD therapy and associated risk factors for these complications.

PATIENTS AND METHODS

Between June 1997 and May 2007, a total of 385 patients with PTBD were identified by analyzing the PTBD database and hospital charts, with a total of 2468 percutaneous biliary drainages being identified.

RESULTS

Among the identified patients, 243 (63%) had malignant and 142 (37%) had benign bile duct strictures. At least 1 drainage-related complication was observed in 40% of the patients. With respect to the total number of drains, prosthesis complications occurred in 23%. Occlusion, dislocation, and cholangitis were the most common complications observed during PTBD therapy. Risk factors for cholangitis and occlusion were malignant disease, prior occurrence of complications, and bilateral drainage. Proximal stenosis of the biliary system was close to significant.

CONCLUSIONS

Drainage-related complications are a major problem in PTBD therapy. The risk factors for occlusion and cholangitis discovered in this study can help to refine individual strategies to reduce the rate of these drainage complications.

Partially covered self-expandable metal stents versus polyethylene stents for malignant biliary obstruction: a cost-effectiveness analysis

BACKGROUND⁄

OBJECTIVE

Partially covered self-expandable metal stents (SEMS) and polyethylene stents (PES) are both commonly used in the palliation of malignant biliary obstruction. Although SEMS are significantly more expensive, they are more efficacious than PES. Accordingly, a cost-effectiveness analysis was performed.

METHODS

A cost-effectiveness analysis compared the approach of initial placement of PES versus SEMS for the study population. Patients with malignant biliary obstruction underwent an endoscopic retrograde cholangiopancreatography to insert the initial stent. If the insertion failed, a percutaneous transhepatic cholangiogram was performed. If stent occlusion occurred, a PES was inserted at repeat endoscopic retrograde cholangiopancreatography, either in an outpatient setting or after admission to hospital if cholangitis was present. A third-party payer perspective was adopted. Effectiveness was expressed as the likelihood of no occlusion over the one-year adopted time horizon. Probabilities were based on a contemporary randomized clinical trial, and costs were issued from national references. Deterministic and probabilistic sensitivity analyses were performed.

RESULTS

A PES-first strategy was both more expensive and less efficacious than an SEMS-first approach. The mean per-patient costs were US$6,701 for initial SEMS and US$20,671 for initial PES, which were associated with effectiveness probabilities of 65.6% and 13.9%, respectively. Sensitivity analyses confirmed the robustness of these results.

CONCLUSION

At the time of initial endoscopic drainage for patients with malignant biliary obstruction undergoing palliative stenting, an initial SEMS insertion approach was both more effective and less costly than a PES-first strategy.

How are palliative care cancer populations characterized in randomized controlled trials? A literature review

CONTEXT

The difficulties in defining a palliative care patient accentuate the need to provide stringent descriptions of the patient population in palliative care research.

OBJECTIVES

To conduct a systematic literature review with the aim of identifying which key variables have been used to describe adult palliative care cancer populations in randomized controlled trials (RCTs).

METHODS

The data sources used were MEDLINE (1950 to January 25, 2010) and Embase (1980 to January 25, 2010), limited to RCTs in adult cancer patients with incurable disease. Forty-three variables were systematically extracted from the eligible articles.

RESULTS

The review includes 336 articles reporting RCTs in palliative care cancer patients. Age (98%), gender (90%), cancer diagnosis (89%), performance status (45%), and survival (45%) were the most frequently reported variables. A large number of other variables were much less frequently reported.

CONCLUSION

A substantial variation exists in how palliative care cancer populations are described in RCTs. Few variables are consistently registered and reported. There is a clear need to standardize the reporting. The results from this work will serve as the basis for an international Delphi process with the aim of reaching consensus on a minimum set of descriptors to characterize a palliative care cancer population.

Does heparin coating reduce encrustation of biliary plastic endoprostheses? A prospective randomized trial

OBJECTIVE

Common bile duct stenting is widely performed for bridging benign and malignant obstructions. A major limitation is early stent occlusion making regular stent exchange necessary. Covalent binding of glycosaminoglycanes to polyethylene stents proved to reduce encrustation in urological implants. Since development of urological and biliary stent occlusion shows parallels, the aim of the study was to evaluate the efficacy of heparin coating of biliary endoprostheses in preventing encrustation.

MATERIAL AND METHODS

In a prospective randomized trial, heparin-coated and native stents were endoscopically placed for almost 90 days on average. After removal, all stents were dried (50°C, 24 h), weighed and after longitudinal incision visible encrustation and discoloration recorded. Fifty-three patients (21 females/32 males, 70 ± 12 (42-87) years) were included; 13 patients (4 females/9 males, 58-79 years) completed the study according to the protocol.

RESULTS

After removal, mean weight of encrustation in native stents was more than double as high as of covered stents (native: 37.9 ± 19.8 (16-93) mg; covered: 17.6 ± 6.7 (9-33) mg). In 12 of 13 cases, the encrustation weight of the native stent was higher than that of the corresponding covered stent in the same patient. Premature stent explantation became necessary in 3 of 13 native stents, because of recurrent jaundice or cholangitis but only in 1 of 13 covered stents. After longitudinal incision, the three uncovered stents showed excessive encrustation whereas no significant encrustation was found in the covered prosthesis. Altogether, covered stents showed less visible accumulation of clogging material and discoloration than native stents.

CONCLUSIONS

Covalent bound heparin is highly effective in preventing encrustation of biliary polyethylene endoprostheses.

Impact of reducing duodenobiliary reflux on biliary stent patency: an in vitro evaluation and a prospective randomized clinical trial that used a biliary stent with an antireflux valve

BACKGROUND

The mechanisms leading to occlusion of plastic biliary stents (PBS) are not known.

OBJECTIVE

To evaluate the impact of reducing duodenobiliary reflux on stent patency rate.

DESIGN

A newly designed antireflux PBS (AR-PBS) was tested in vitro by using ox bile. A prospective randomized trial in human beings was conducted.

SETTING

Tertiary medical center.

PATIENTS

Patients with malignant bile-duct strictures were studied.

INTERVENTIONS

A PBS or an AR-PBS stent was placed by using standard techniques, and the patients were followed at regular intervals. Patients presenting with stent occlusion underwent re-stent placement with either a PBS or a metal stent.

MAIN OUTCOME MEASUREMENTS

In vitro: resistance to retrograde flow and comparison of the basal and peak antegrade flow pressures between the 2 stents. In vivo: stent patency rates, complications, and the efficacy of the stents in improving the liver test.

RESULTS

The AR-PBS stent could withstand a retrograde pressure gradient of >320 mm Hg compared with <1 mm Hg for the PBS. Secondary to the siphon effect of the valve, the antegrade flow resistance offered by the AR-PBS was on the negative side for all flow rates compared with PBS (P < .001). The median patency of the AR-PBS in human studies was 145 days (range, 52-252 days) compared with 101 days (range, 41-210 days) for the PBS (P = .002). Both stents were equally effective in improving the liver test, and complication rates were similar in the 2 groups.

LIMITATIONS

The occluded stents were not examined microscopically.

CONCLUSIONS

The antireflux biliary stent remains patent for a longer time and hence duodenobiliary reflux may be contributing to stent occlusion.

Plastic biliary stent occlusion: factors involved and possible preventive approaches

Endoscopic biliary stenting is today the most common palliative treatment for patients suffering from obstructive jaundice associated with malignant hepatobiliary tumors or benign strictures. However, recurrent jaundice, with or without cholangitis, is a major complication of a biliary endoprosthesis insertion. Thus, stent removal and replacement with a new one frequently occurs as a consequence of device blockage caused by microbial biofilm growth and biliary sludge accumulation in the lumen. Factors and mechanisms involved in plastic stent clogging arising from epidemiological, clinical and experimental data, as well as the possible strategies to prevent biliary stent failure, will be reviewed and discussed.

Malignant distal biliary obstruction: a systematic review and meta-analysis of endoscopic and surgical bypass results

BACKGROUND

Surgical bypass and endoscopic stents are available for palliative bypass of malignant distal biliary obstruction.

AIM

Comparison of reported outcomes in randomized controlled trials (RCTs) which included surgery, endoscopic plastic stents or endoscopic metal stents in palliative relief of malignant distal biliary obstruction.

METHODS

Systematic review and meta-analysis of published literature and conference proceedings review to June 2006.

RESULTS

We found 24 studies, containing 2436 patients, which met our inclusion criteria. Endoscopic stenting with plastic stents (three studies) is associated with a lower risk of complications (RR 0.60, 95% CI 0.45-0.81), but a higher risk of recurrent biliary obstruction (RR 18.59, 95% CI 5.33 -64.86) than traditional surgical bypass. Self-expanding metal stents (seven studies) are associated with a significantly reduced risk of recurrent biliary obstruction at 4 months (RR 0.44, 95% CI 0.3, 0.63), or prior to death or end of study (RR 0.52, 95% CI 0.39-0.69), but are not superior to plastic stents in terms of technical success, therapeutic success, mortality or complications. Cost-effectiveness outcomes were not suitable for meta-analysis. No other plastic stent designs have been demonstrated to be superior to polyethylene stents (12 studies).

CONCLUSIONS

Endoscopic metal stents are the intervention of choice in patients with malignant distal biliary obstruction, producing similar outcomes to plastic stents, but with improved patency rates.

Palliative biliary stents for obstructing pancreatic carcinoma

BACKGROUND

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

OBJECTIVES

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

SEARCH STRATEGY

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

SELECTION CRITERIA

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

DATA COLLECTION AND ANALYSIS

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

MAIN RESULTS

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

AUTHORS' CONCLUSIONS

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

Evaluating Surgical Outcomes

The study of outcomes has become essential for guiding quality of-care assessment and for clinical research. In this article, the properties and process of patient outcomes measurement are described. The limitations of traditional outcomes are discussed and contrasted with the emerging concept of "patient-centered"outcomes, measured by validated instruments to assess the effects of surgical interventions on health-related quality of life, functional status, pain, and patient satisfaction. The strengths and weaknesses of several measurement tools used in the surgical literature are evaluated. Finally, the authors introduce "composite outcomes" as a reflection of the multidimensional nature of modern patient care.

Palliative biliary stents for obstructing pancreatic carcinoma

BACKGROUND

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

OBJECTIVES

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

SEARCH STRATEGY

We searched the databases of the Cochrane Upper Gastrointestinal and Pancreatic Group specialised register, Cochrane Central Register of Controlled Trials , MEDLINE, EMBASE, CancerLit, Current Concepts Database and BIDS (September 2002 to September 2004). Reference lists of articles and published abstracts from UEGW and DDW were hand-searched.

SELECTION CRITERIA

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

DATA COLLECTION AND ANALYSIS

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

MAIN RESULTS

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

AUTHORS' CONCLUSIONS

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