Self-expandable metal stents (SEMS) are used in patients with malignant distal biliary obstruction.
Trials that compared covered and uncovered SEMS reported different results because of heterogeneous designs and patient populations.
These studies compared patency of uncovered SEMS and covered SEMS, along with rates of pancreatitis, cholecystitis, cholangitis, SEMS migration, bleeding, perforation, and recurrent biliary obstruction.
Dr Majid Almadi and colleagues from Canada performed a meta-analysis to compare the effects of covered and uncovered SEMS in patients with malignant distal biliary obstruction.
The researchers identified randomized controlled trials by using a literature search from 1980 through 2012.
The research team observed evaluated data from 5 full articles and 4 abstracts, comprising 1061 patients, and assessed statistical heterogeneity and publication bias.
The weighted mean difference in the stent patency duration could only be calculated on the basis of 2 studies, but it was 68 days longer for covered SEMS than for uncovered SEMS.
|Patients with covered SEMS had a higher rate of tumor overgrowth|
|Clinical Gastroenterology & Hepatology|
The doctors noted that a summary analysis of data from 4 trials demonstrated no differences in patency of covered vs uncovered SEMS after 6 months or 12 months.
There were also no differences in the rates of pancreatitis, cholecystitis, perforation, bleeding, or cholangitis, length of hospital stay, or number of recurrent biliary obstructions.
The researches found that covered SEMS had a higher migration rate.
Patients with covered SEMS had a lower rate of tumor ingrowth but a higher rate of tumor overgrowth.
The research team reported that no summary calculations could be completed to confidently assess patient survival.
Dr Almadi's team concluded, "The use of covered SEMS, compared with uncovered SEMS, in patients with distal malignant biliary obstruction is of unclear benefit."
"Covered SEMS have a higher rate of migration and do not appear to have longer patency."