title: A prospective randomized trial of Teflon versus polyethylene stents for distal malignant biliary obstruction.
abstract: OBJECTIVE
  Clogging of biliary stents continues to be a major clinical problem. Different polymer materials may have different effects on clogging. In vitro studies have shown a direct relation between the frictional coefficient of a polymer and the amount of encrusted material. Teflon appeared to be the best polymer for biliary stents. Two different types of stents made of Teflon have been tested in clinical practice and showed favourable patency rates. However, a randomized trial has never been performed. We compared the patency of an Amsterdam-type polyethylene stent with a Teflon stent in a prospective randomized trial.
  
  
  METHODS
  Between September 1995 and November 1996, 42 patients received a Teflon stent and 42 patients a polyethylene stent. All patients had a distal malignant biliary stricture without a previous drainage procedure. Diagnoses included carcinoma of the pancreas (n = 76), papilla (n = 1), bile duct (n = 5) and metastases (n = 2). The internal and external diameter (10 Fr), length (9 cm) and stent design (a straight stent with two side flaps and one side hole at each end) were similar for both stents.
  
  
  RESULTS
  A reduction in bilirubin of more than 20% within one week was seen in 91% of the patients. Early complication rates were similar in both groups (10%). The median follow-up was 142 days. Stent dysfunction occurred in 28 Teflon and 29 polyethylene stents. The thirty-day mortality was 14% in both groups. Patient survival did not differ significantly between the groups (median survival: Teflon 165 days, polyethylene 140 days). The median stent patency was 83 days for Teflon and 80 days for polyethylene stents, and was not significantly different either.
  
  
  CONCLUSIONS
  Teflon material did not improve patency in biliary stents with an Amsterdam-type design.
authors.affiliation: Dept. of Gastroenterology, Academic Medical Center, University of Amsterdam, The Netherlands.
authors.forename: A M
authors.initials: AM
authors.lastname: van Berkel
authors.forename: C
authors.initials: C
authors.lastname: Boland
authors.forename: W K
authors.initials: WK
authors.lastname: Redekop
authors.forename: J J
authors.initials: JJ
authors.lastname: Bergman
authors.forename: A K
authors.initials: AK
authors.lastname: Groen
authors.forename: G N
authors.initials: GN
authors.lastname: Tytgat
authors.forename: K
authors.initials: K
authors.lastname: Huibregtse
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001650:Bile Duct Neoplasms / Q000150:complications / Q000175:diagnosis / Q000401:mortality / Q000628:therapy*; D002760:Cholangiopancreatography, Endoscopic Retrograde / Q000295:instrumentation* / Q000379:methods; D002779:Cholestasis / Q000175:diagnosis / Q000209:etiology / Q000401:mortality / Q000628:therapy*; D003135:Common Bile Duct; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008422:Materials Testing; D008875:Middle Aged; D011095:Polyethylenes / Q000009:adverse effects; D011138:Polytetrafluoroethylene / Q000009:adverse effects; D011446:Prospective Studies; D011474:Prosthesis Design; D018709:Statistics, Nonparametric; D015607:Stents / Q000009:adverse effects; D015996:Survival Rate; D016896:Treatment Outcome
chemical_list: D011095:Polyethylenes; D011138:Polytetrafluoroethylene