title: Safety and Efficacy of Percutaneous Biliary Covered Stent Placement in Patients with Malignant Biliary Hilar Obstruction; Correlation with Liver Function.
abstract: OBJECTIVE
  To estimate the safety and efficacy of percutaneous ePTFE-covered biliary stent placement and the relationship between underlying liver function and stent patency in patients with malignant hilar obstruction.
  
  
  METHODS
  From March 2012 to June 2015, 41 patients [22 females, 19 males; mean age 69.8 (range 34-94) years] with malignant biliary obstruction underwent percutaneous biliary stent placement (31 patients with unilateral, 10 patients with bilateral side-by-side). Cumulative patient survival and stent patency rate curves were derived using the Kaplan-Meier method. A Cox model was used to explore the relationship between liver function and patient survival, and also biliary stent patency. Pearson correlation coefficient was used to analyze the relationship between patient survival and stent patency.
  
  
  RESULTS
  Technical success rate was 100 % and clinical success rate was 95 %. During follow-up, four complications occurred (two bilomas and two cases of acute cholecystitis) and were treated successfully with percutaneous drainage. No other complication occurred. Mean serum bilirubin level was 11.34 ± 7.35 mg/dL before drainage and 5.00 ± 4.83 mg/dL 2 weeks after stent placement. The median patent survival duration was 147 days (95 % CI, 69.6-224.4 days). The median stent patency duration was 101 days (95 % CI, 70.0-132.0 days). The cumulative stent patency rates at 1, 3, 6, and 12 months were 97, 57.6, 30.3, and 17.0 %, respectively. Child-Pugh score was correlated significantly with patient survival (P = 0.011) and stent patency (P = 0.007). MELD score was correlated significantly with stent patency (P = 0.044). There was a correlation between patient survival and stent patency (r = 0.778, P < 0.001).
  
  
  CONCLUSIONS
  Percutaneous placement of ePTFE-covered biliary stent was a safe and an effective method for malignant biliary obstruction. Underlying liver function seemed to be one of the important factors affecting patient survival and stent patency, and stent patency showed statistically significant correlation with patient survival.
authors.affiliation: Department of Radiology and Medical Research Institute, School of Medicine Ewha Womans University, 1071 Anyangcheon-ro, Yangcheon-gu, Seoul, 158-710, Republic of Korea.
authors.forename: Hyeran
authors.initials: H
authors.lastname: Hyun
authors.affiliation: Department of Radiology and Medical Research Institute, School of Medicine Ewha Womans University, 1071 Anyangcheon-ro, Yangcheon-gu, Seoul, 158-710, Republic of Korea. medmath@hanmail.net.
authors.forename: Sun Young
authors.initials: SY
authors.lastname: Choi
authors.affiliation: Department of Radiology, St. Vincent's Hospital, The Catholic University of Korea, Suwon, Gyeonggi-do, 442-723, Republic of Korea.
authors.forename: Kyung Ah
authors.initials: KA
authors.lastname: Kim
authors.affiliation: Department of Biology, College of Arts and Science Case Western Reserve University, 10900 Euclid Ave, Cleveland, OH, 44106, USA.
authors.forename: Soo Bin
authors.initials: SB
authors.lastname: Ko
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001650:Bile Duct Neoplasms / Q000150:complications* / Q000601:surgery*; D001652:Bile Ducts / Q000601:surgery; D002779:Cholestasis / Q000150:complications* / Q000601:surgery*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008099:Liver / Q000502:physiology*; D008111:Liver Function Tests; D008297:Male; D008875:Middle Aged; D016016:Proportional Hazards Models; D015607:Stents; D016019:Survival Analysis; D016896:Treatment Outcome; D014654:Vascular Patency / Q000502:physiology
keywords: Biliary stent placement; Covered stent; Malignant hilar obstruction