title: Inferior vena cava filters for prevention of venous thromboembolism in obese patients undergoing bariatric surgery: a systematic review.
abstract: OBJECTIVE
  The use of inferior vena cava (IVC) filters for prevention of venous thromboembolism (VTE) in bariatric surgery is a contentious issue. We aim to review the evidence for the use of IVC filters in bariatric surgical patients, describe trends in practice, and discuss challenges in developing evidence-based guidelines.
  
  
  BACKGROUND
  The incidence of VTE in modern bariatric procedures with traditional methods of thromboprophylaxis, such as sequential calf compression devices and perioperative low molecular weight heparin, is approximately 2%.
  
  
  METHODS
  A systematic review of the literature was conducted according to PRISMA guidelines. We searched Medline up until July 2013 with the terms "bariatric filter" and "gastric bypass filter." Two investigators independently screened search results according to an agreed list of eligibility criteria.
  
  
  RESULTS
  Eighteen studies were included. There were no randomized controlled trials. Data from controlled cohort studies suggest that those who undergo IVC filter insertion preoperatively may be at higher risk of developing deep vein thrombosis (DVT) and pulmonary embolism (PE). A small cohort of patients with multiple risk factors for VTE benefitted from reduced PE-related mortality after preoperative IVC filter insertion. Data from 12 case series reporting VTE outcomes from a total of 497 patients who underwent preoperative IVC filter insertion demonstrated DVT rates of 0% to 20.8% and PE rates ranging from 0% to 6.4%.
  
  
  CONCLUSIONS
  Published data reporting the safety and efficacy of IVC filter use in bariatric surgical patients is highly heterogeneous. There is no evidence to suggest that the potential benefits of IVC filters outweigh the significant risks of therapy.
authors.affiliation: *Academic Section of Vascular Surgery, Imperial College London, Charing Cross Hospital, Fulham Palace Road, London, United Kingdom †Department of Anaesthetics, Imperial College Healthcare NHS Trust, Charing Cross Hospital, Fulham Palace Road, London, United Kingdom; and ‡Department of General and Bariatric Surgery, Imperial College Healthcare NHS Trust, Charing Cross Hospital, Fulham Palace Road, London, United Kingdom.
authors.forename: Simon P
authors.initials: SP
authors.lastname: Rowland
authors.forename: Brahman
authors.initials: B
authors.lastname: Dharmarajah
authors.forename: Hayley M
authors.initials: HM
authors.lastname: Moore
authors.forename: Tristan R A
authors.initials: TR
authors.lastname: Lane
authors.forename: Jonathan
authors.initials: J
authors.lastname: Cousins
authors.forename: Ahmed R
authors.initials: AR
authors.lastname: Ahmed
authors.forename: Alun H
authors.initials: AH
authors.lastname: Davies
mesh_terms: D050110:Bariatric Surgery / Q000009:adverse effects*; D004869:Equipment Safety; D006801:Humans; D009767:Obesity, Morbid / Q000601:surgery*; D012307:Risk Factors; D016306:Vena Cava Filters / Q000009:adverse effects; D054556:Venous Thromboembolism / Q000517:prevention & control*