title: A prospective, multicenter study of a double stent system for palliative treatment of malignant extrahepatic biliary obstructions.
abstract: BACKGROUND
  A double stent system (covered stent in uncovered stent) was designed to provide long-term patency without tumor ingrowth or stent-related complications, such as stent migration, cholecystitis, or pancreatitis.
  
  
  OBJECTIVE
  To investigate the safety and efficacy of double stents in patients with malignant extrahepatic biliary obstructions.
  
  
  METHODS
  This prospective, nonrandomized, multicenter study enrolled 160 consecutive patients (102 men; mean age, 64 years; range, 33-91 years) with malignant extrahepatic biliary obstructions treated with a double stent system from January 2010 to March 2012.
  
  
  RESULTS
  The technical success rate of the double stent placement was 100%. No stent migration was observed. Procedure-related minor (self-limiting hemobilia [n = 6] and cholangitis [n = 2]) and major (pancreatitis [n = 16], cholecystitis [n = 3], and hepatic abscess [n = 2]) complications occurred in a total of 29 patients. The mean serum bilirubin level, which was 8.9 ± 5.6 mg/dL before drainage, decreased to 2.2 ± 4.6 mg/dL 1 month after stent placement (P < 0.001). Successful internal drainage was achieved in 148 patients (92.5%). During the mean follow-up period of 205 days, acute cholecystitis (n = 3) and hepatic abscess (n = 2) occurred in five patients. The median patient survival and stent patency time were 135 days (95% confidence interval [CI], 96-160 days) and 114 days (95% CI, 83-131 days), respectively. Of 153 patients, 22 (14.4%) presented with stent dysfunction due to sludge incrustation (n = 17), tumor overgrowth (n = 4), or blood clot (n = 1), and required repeat intervention. Tumor ingrowth was not observed in any of these patients.
  
  
  CONCLUSIONS
  Percutaneous treatment of malignant extrahepatic biliary obstruction using a double stent safely and effectively achieves internal biliary drainage.
authors.affiliation: Department of Radiology and Research Institute of Radiology, University of Ulsan College of Medicine, Asan Medical Center, Republic of Korea.
authors.forename: Jong Woo
authors.initials: JW
authors.lastname: Kim
authors.affiliation: Department of Radiology and Research Institute of Radiology, University of Ulsan College of Medicine, Asan Medical Center, Republic of Korea radgwon@amc.seoul.kr.
authors.forename: Dong   Il
authors.initials: D
authors.lastname: Gwon
authors.affiliation: Department of Radiology, Chonbuk National University Medical School and Hospital, Republic of Korea.
authors.forename: Young-Min
authors.initials: YM
authors.lastname: Han
authors.affiliation: Department of Radiology, Ajou University college of Medicine and Hospital, Republic of Korea.
authors.forename: Je Hwan
authors.initials: JH
authors.lastname: Won
authors.affiliation: Department of Radiology, Sungkyunkwan University School of Medicine, Kangbuk Samsung Hospital, Republic of Korea.
authors.forename: Hyun Pyo
authors.initials: HP
authors.lastname: Hong
authors.affiliation: Department of Radiology and Research Institute of Radiology, University of Ulsan College of Medicine, Asan Medical Center, Republic of Korea.
authors.forename: Gi-Young
authors.initials: GY
authors.lastname: Ko
authors.affiliation: Department of Radiology and Research Institute of Radiology, University of Ulsan College of Medicine, Asan Medical Center, Republic of Korea.
authors.forename: Hyun-Ki
authors.initials: HK
authors.lastname: Yoon
authors.affiliation: Department of Radiology and Research Institute of Radiology, University of Ulsan College of Medicine, Asan Medical Center, Republic of Korea.
authors.forename: Kyu-Bo
authors.initials: KB
authors.lastname: Sung
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001650:Bile Duct Neoplasms / Q000150:complications*; D002779:Cholestasis / Q000209:etiology* / Q000628:therapy*; D004322:Drainage / Q000295:instrumentation; D004867:Equipment Design; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010166:Palliative Care / Q000379:methods*; D011446:Prospective Studies; D015607:Stents / Q000009:adverse effects; D015996:Survival Rate; D016896:Treatment Outcome
keywords: Malignant extrahepatic biliary obstruction; biliary stent; double stent system