Meta-analysis of randomized trials comparing the patency of covered and uncovered self-expandable metal stents for palliation of distal malignant bile duct obstruction

Department of Internal Medicine, Mayo Clinic, College of Medicine, Rochester, Minnesota, USA.
Gastrointestinal endoscopy (Impact Factor: 5.37). 06/2011; 74(2):321-327.e1-3. DOI: 10.1016/j.gie.2011.03.1249
Source: PubMed


Self-expandable metal stents (SEMSs) are used for palliation of malignant biliary obstruction.
We performed a meta-analysis to compare stent patency and stent survival of covered SEMSs (CSEMSs) and uncovered SEMSs (USEMSs) in patients with unresectable distal malignant biliary obstruction.
Tertiary-care facility.
A comprehensive search of several databases (from each database's earliest inclusive dates to November 2010, any language, and any population) was conducted. The search identified 337 potential abstracts and titles, of which 16 were retrieved in full text. Review of references identified 17 additional studies. We found 5 multicenter, randomized trials involving 781 patients.
Placement of covered and uncovered SEMSs for treatment of distal malignant biliary obstruction.
Stent patency, stent survival, patient survival, and cause for stent dysfunction (ingrowth, overgrowth, migration, and sludge formation).
The median length of follow-up was 212 days. Compared with USEMSs, CSEMSs were associated with significantly prolonged stent patency (weighted mean difference [WMD] 60.56 days; 95% confidence interval [CI], 25.96, 95.17; I² = 0%) and longer stent survival (WMD 68.87 days; 95% CI, 25.64, 112.11; I(2) = 79%). Stent migration, tumor overgrowth, and sludge formation were significantly higher with CSEMSs (relative risk [RR] 8.11; 95% CI, 1.47, 44.76; I² = 0%), (RR 2.02; 95% CI, 1.08, 3.78; I² = 0%), (RR 2.89; 95% CI, 1.27, 6.55; I² = 0%).
Relatively low number of studies available and the fact that 2 of the 5 studies were from one institution. Also, the limited availability of some stents used in the trials may limit the applicability of these results.
CSEMSs have a significantly longer duration of patency compared with USEMSs in patients with distal malignant biliary obstruction. Stent dysfunction occurs at a similar rate, although there is a trend toward later obstruction with CSEMSs.

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    • "In addition, we included one study (11) in which a percutaneous approach to stent placement was used exclusively. Saleem et al. (17) noted that although insertion complications differ when stents are placed percutaneously compared with those placed endoscopically, the method of stent placement does not affect the subsequent stent outcome. Moreover, patients with various disease etiologies were included; hence, this analysis does not differentiate the performance of the SBS versus SIS techniques according to the causes of hilar biliary strictures, thus limiting the generalizability of these results. "
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    ABSTRACT: OBJECTIVE: There is no consensus regarding the most appropriate methods (i.e., the side-by-side versus the stent-in-stent technique) for placing bilateral stents for malignant hilar biliary obstructions. We aimed to perform a quantitative review of the published data regarding the clinical efficacy of the side-by-side and stent-in-stent bilateral drainage techniques for hilar biliary obstructions. METHODS: A comprehensive search of several databases was conducted and a fixed-effects or random-effects model was used to pool the data from all of the study end-points. RESULTS: Four clinical trials were identified. A comparison of the side-by-side and stent-in-stent groups revealed no significant differences with respect to the rates of successful placement, successful drainage, early complications, late complications and stent occlusions. There were also no significant inter-group differences in stent patency and patient survival and no publication bias was observed. CONCLUSIONS: The performance of the side-by-side technique appears to be similar to that of the stent-in-stent technique for bilateral drainage in patients with malignant hilar biliary obstructions.
    Full-text · Article · Sep 2014 · Clinics (São Paulo, Brazil)
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    • "Despite the extended patency of C-SEMSs, the high rate of complications compared to uncovered SEMSs (U-SEMSs) is a major concern.2 Stent migration remains an unresolved complication of C-SEMSs. "
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    ABSTRACT: 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. 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. 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. m-CZSs with antimigration properties effectively, although not completely, prevented stent migration after stent insertion.
    Full-text · Article · Nov 2013 · Gut and Liver
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    • "So patients with cancerous gastrointestinal obstruction could not ultimately obtain more survival benefit from the covered stents. Moreover, biofilms might develop and attach the coating surface in a similar way to those in plastic stents 2,9. Nevertheless, covered stents were easier to be removed if necessary than bare stents whose metal meshes were embedded in the tumor tissue. "
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    ABSTRACT: 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.
    Full-text · Article · Apr 2013 · International journal of medical sciences
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