title: Effect of Covered Metallic Stents Compared With Plastic Stents on Benign Biliary Stricture Resolution: A Randomized Clinical Trial.
abstract: OBJECTIVE
  Endoscopic placement of multiple plastic stents in parallel is the first-line treatment for most benign biliary strictures; it is possible that fully covered, self-expandable metallic stents (cSEMS) may require fewer endoscopic retrograde cholangiopancreatography procedures (ERCPs) to achieve resolution.
  
  
  OBJECTIVE
  To assess whether use of cSEMS is noninferior to plastic stents with respect to stricture resolution.
  
  
  METHODS
  Multicenter (8 endoscopic referral centers), open-label, parallel, randomized clinical trial involving patients with treatment-naive, benign biliary strictures (N = 112) due to orthotopic liver transplant (n = 73), chronic pancreatitis (n = 35), or postoperative injury (n = 4), who were enrolled between April 2011 and September 2014 (with follow-up ending October 2015). Patients with a bile duct diameter less than 6 mm and those with an intact gallbladder in whom the cystic duct would be overlapped by a cSEMS were excluded.
  
  
  METHODS
  Patients (N = 112) were randomized to receive multiple plastic stents or a single cSEMS, stratified by stricture etiology and with endoscopic reassessment for resolution every 3 months (plastic stents) or every 6 months (cSEMS). Patients were followed up for 12 months after stricture resolution to assess for recurrence.
  
  
  METHODS
  Primary outcome was stricture resolution after no more than 12 months of endoscopic therapy. The sample size was estimated based on the noninferiority of cSEMS to plastic stents, with a noninferiority margin of -15%.
  
  
  RESULTS
  There were 55 patients in the plastic stent group (mean [SD] age, 57 [11] years; 17 women [31%]) and 57 patients in the cSEMS group (mean [SD] age, 55 [10] years; 19 women [33%]). Compared with plastic stents (41/48, 85.4%), the cSEMS resolution rate was 50 of 54 patients (92.6%), with a rate difference of 7.2% (1-sided 95% CI, -3.0% to ∞; P < .001). Given the prespecified noninferiority margin of -15%, the null hypothesis that cSEMS is less effective than plastic stents was rejected. The mean number of ERCPs to achieve resolution was lower for cSEMS (2.14) vs plastic (3.24; mean difference, 1.10; 95% CI, 0.74 to 1.46; P < .001).
  
  
  CONCLUSIONS
  Among patients with benign biliary strictures and a bile duct diameter 6 mm or more in whom the covered metallic stent would not overlap the cystic duct, cSEMS were not inferior to multiple plastic stents after 12 months in achieving stricture resolution. Metallic stents should be considered an appropriate option in patients such as these.
  
  
  BACKGROUND
  clinicaltrials.gov Identifier: NCT01221311.
authors.affiliation: Department of Medicine, Indiana University School of Medicine, Indianapolis2Department of Medicine, Medical University of South Carolina, Charleston.
authors.forename: Gregory A
authors.initials: GA
authors.lastname: Coté
authors.affiliation: Department of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania.
authors.forename: Adam
authors.initials: A
authors.lastname: Slivka
authors.affiliation: Methodist Dallas Medical Center, Dallas, Texas.
authors.forename: Paul
authors.initials: P
authors.lastname: Tarnasky
authors.affiliation: Department of Medicine, Washington University in St Louis, St Louis, Missouri.
authors.forename: Daniel K
authors.initials: DK
authors.lastname: Mullady
authors.affiliation: Department of Medicine, Medical University of South Carolina, Charleston6Department of Medicine, University of Michigan, Ann Arbor.
authors.forename: B Joseph
authors.initials: BJ
authors.lastname: Elmunzer
authors.affiliation: Department of Medicine, University of Michigan, Ann Arbor.
authors.forename: Grace
authors.initials: G
authors.lastname: Elta
authors.affiliation: Department of Medicine, Indiana University School of Medicine, Indianapolis.
authors.forename: Evan
authors.initials: E
authors.lastname: Fogel
authors.affiliation: Department of Medicine, Indiana University School of Medicine, Indianapolis.
authors.forename: Glen
authors.initials: G
authors.lastname: Lehman
authors.affiliation: Department of Medicine, Indiana University School of Medicine, Indianapolis.
authors.forename: Lee
authors.initials: L
authors.lastname: McHenry
authors.affiliation: Department of Medicine, Medical University of South Carolina, Charleston.
authors.forename: Joseph
authors.initials: J
authors.lastname: Romagnuolo
authors.affiliation: Royal Wolverhampton Trust, Wolverhampton, United Kingdom.
authors.forename: Shyam
authors.initials: S
authors.lastname: Menon
authors.affiliation: Center for Endoscopic Research and Therapeutics, University of Chicago School of Medicine, Chicago, Illinois.
authors.forename: Uzma D
authors.initials: UD
authors.lastname: Siddiqui
authors.affiliation: Department of Medicine, Indiana University School of Medicine, Indianapolis.
authors.forename: James
authors.initials: J
authors.lastname: Watkins
authors.affiliation: Department of Medicine, Indiana University School of Medicine, Indianapolis.
authors.forename: Sheryl
authors.initials: S
authors.lastname: Lynch
authors.affiliation: Department of Biostatistics, Indiana University School of Medicine, Indianapolis.
authors.forename: Cheryl
authors.initials: C
authors.lastname: Denski
authors.affiliation: Department of Biostatistics, Indiana University School of Medicine, Indianapolis.
authors.forename: Huiping
authors.initials: H
authors.lastname: Xu
authors.affiliation: Department of Medicine, Indiana University School of Medicine, Indianapolis.
authors.forename: Stuart
authors.initials: S
authors.lastname: Sherman
mesh_terms: D002760:Cholangiopancreatography, Endoscopic Retrograde / Q000009:adverse effects / Q000706:statistics & numerical data; D002779:Cholestasis / Q000209:etiology / Q000628:therapy*; D003251:Constriction, Pathologic / Q000209:etiology / Q000628:therapy; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010969:Plastics; D011183:Postoperative Complications / Q000628:therapy; D019919:Prosthesis Implantation; D018401:Sample Size; D000069322:Self Expandable Metallic Stents / Q000009:adverse effects; D015607:Stents / Q000009:adverse effects
chemical_list: D010969:Plastics