title: Treatment of malignant biliary obstruction with a PTFE-covered self-expandable nitinol stent.
abstract: OBJECTIVE
  We wanted to determine the technical and clinical efficacy of using a PTFE-covered self-expandable nitinol stent for the palliative treatment of malignant biliary obstruction.
  
  
  METHODS
  Thirty-seven patients with common bile duct strictures caused by malignant disease were treated by placing a total of 37 nitinol PTFE stents. These stents were covered with PTFE with the exception of the last 5 mm at each end; the stent had an unconstrained diameter of 10 mm and a total length of 50-80 mm. The patient survival rate and stent patency rate were calculated by performing Kaplan-Meier survival analysis. The bilirubin, serum amylase and lipase levels before and after stent placement were measured and then compared using a Wilcoxon signed-rank test. The average follow-up duration was 27.9 weeks (range: 2-81 weeks).
  
  
  RESULTS
  Placement was successful in all cases. Seventy-six percent of the patients (28/37) experienced adequate palliative drainage for the remainder of their lives. There were no immediate complications. Three patients demonstrated stent sludge occlusion that required PTBD (percutaneous transhepatic biliary drainage) irrigation. Two patients experienced delayed stent migration with stone formation at 7 and 27 weeks of follow-up, respectively. Stent insertion resulted in acute elevations of the amylase and lipase levels one day after stent insertion in 11 patients in spite of performing endoscopic sphincterotomy (4/6). The bilirubin levels were significantly reduced one week after stent insertion (p < 0.01). The 30-day mortality rate was 8% (3/37), and the survival rates were 49% and 27% at 20 and 50 weeks, respectively. The primary stent patency rates were 85%, and 78% at 20 and 50 weeks, respectively.
  
  
  CONCLUSIONS
  The PTFE-covered self-expandable nitinol stent is safe to use with acceptable complication rates. This study is similar to the previous studies with regard to comparing the patency rates and survival rates.
authors.affiliation: Department of Radiology, Chonbuk National University Medical School and Hospital, Chonju, Korea. ymhan@chonbuk.ac.kr
authors.forename: Young-Min
authors.initials: YM
authors.lastname: Han
authors.forename: Hyo-Sung
authors.initials: HS
authors.lastname: Kwak
authors.forename: Gong-Yong
authors.initials: GY
authors.lastname: Jin
authors.forename: Seung-Ok
authors.initials: SO
authors.lastname: Lee
authors.forename: Gyung-Ho
authors.initials: GH
authors.lastname: Chung
mesh_terms: D000230:Adenocarcinoma / Q000150:complications*; D000368:Aged; D000369:Aged, 80 and over; D000497:Alloys / Q000009:adverse effects / Q000627:therapeutic use*; D001651:Cholestasis, Extrahepatic / Q000209:etiology / Q000601:surgery*; D020099:Coated Materials, Biocompatible / Q000627:therapeutic use*; D003135:Common Bile Duct / Q000000981:diagnostic imaging / Q000601:surgery; D004067:Digestive System Neoplasms / Q000150:complications*; D004867:Equipment Design; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D010166:Palliative Care / Q000379:methods; D010865:Pilot Projects; D011138:Polytetrafluoroethylene / Q000009:adverse effects / Q000627:therapeutic use*; D011183:Postoperative Complications / Q000175:diagnosis / Q000453:epidemiology; D011446:Prospective Studies; D011859:Radiography; D015607:Stents / Q000009:adverse effects; D016019:Survival Analysis; D016896:Treatment Outcome
chemical_list: D000497:Alloys; D020099:Coated Materials, Biocompatible; C013616:nitinol; D011138:Polytetrafluoroethylene