title: Indications, complications and outcomes of inferior vena cava filters: A retrospective study.
abstract: BACKGROUND
  Inferior vena cava filters are used to prevent embolization of a lower extremity deep vein thrombosis when the risk of pulmonary embolism is thought to be high. However, evidence is lacking for their benefit and guidelines differ on the recommended indications for filter insertion. The study aim was to determine the reasons for inferior vena cava filter placement and subsequent complication rate.
  
  
  METHODS
  A retrospective cohort of patients receiving inferior vena cava filters in Edmonton, Alberta, Canada from 2007 to 2011. Main outcome was the indication of inferior vena cava filter insertion. Other measures include baseline demographic and medical history of patients, clinical outcomes and filter retrieval rates.
  
  
  RESULTS
  464 patients received inferior vena cava filters. An acute deep vein thrombosis with a contraindication to anticoagulation was the indication for 206 (44.4%) filter insertions. No contraindication to anticoagulation could be identified in 20.7% of filter placements. 30.6% were placed in those with active cancer, in which mortality was significantly higher. Only 38.9% of retrievable filters were successfully retrieved.
  
  
  CONCLUSIONS
  Inferior vena cava filters were placed frequently in patients with weak or no guideline-supported indications for filter placement and in up to 20% of patients with no contraindication to anticoagulation. The high rates of cancer and the high mortality rate of the cohort raise the possibility that some filters are placed inappropriately in end of life settings.
authors.affiliation: Division of General Internal Medicine, Department of Medicine, University of Alberta, Edmonton, Canada.
authors.forename: Andrew
authors.initials: A
authors.lastname: Wassef
authors.affiliation: Division of Hematology & Thromboembolism, Department of Medicine, McMaster University, Hamilton, Canada.
authors.forename: Wendy
authors.initials: W
authors.lastname: Lim
authors.affiliation: Division of Hematology, Department of Medicine, University of Alberta, Edmonton, Canada. Electronic address: cwu@ualberta.ca.
authors.forename: Cynthia
authors.initials: C
authors.lastname: Wu
mesh_terms: D000368:Aged; D000925:Anticoagulants / Q000627:therapeutic use; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009369:Neoplasms / Q000150:complications*; D011655:Pulmonary Embolism / Q000209:etiology / Q000517:prevention & control; D012189:Retrospective Studies; D016896:Treatment Outcome; D016306:Vena Cava Filters / Q000009:adverse effects; D014682:Vena Cava, Inferior / Q000601:surgery; D020246:Venous Thrombosis / Q000150:complications / Q000628:therapy*
chemical_list: D000925:Anticoagulants
keywords: Deep vein thrombosis; Inferior vena cava filter; Pulmonary embolism; Venous thromboembolism