title: Prospective randomized study comparing the clinical outcomes between inferior vena cava Greenfield and TrapEase filters.
abstract: OBJECTIVE
  Although anticoagulation remains the mainstay of treatment for deep venous thrombosis, the use of inferior vena cava (IVC) filters when anticoagulation has failed or when contraindicated remains a safe and effective treatment. Greenfield (Boston Scientific, Natick, Mass) and TrapEase (Cordis, Bridgewater, NJ) filters are arguably among the most popular filtration devices. The Greenfield filter (12F introducer) has been in use for >30 years and has been well studied. The TrapEase filter (6F introducer) has been used since 2000, with a limited number of studies. Good guidelines to help determine which filter to use in any given situation are lacking; therefore, this randomized study prospectively compared the clinical outcomes (access-site thrombosis, filter thrombosis, and symptomatic pulmonary embolism [PE]) between these filters.
  
  
  METHODS
  Between July 2006 and November 2008, 156 patients (63 men, 93 women; mean age, 75 years; range, 38-101 years) were randomized: 84 to Greenfield and 72 to TrapEase IVC filter insertion in the infrarenal position using angiographic guidance. Postoperative follow-up comprised serial lower extremity and IVC/iliac vein (IV) duplex imaging (78.2%) at day 1, week 1, every 3 months for the first year, and every 6 months for the second year; clinical evaluation, and clinic visits. During this period, 349 patients (143 men, 206 women; mean age, 75 years; range, 24-96 years) were not randomized.
  
  
  RESULTS
  The indications for filter placement, in the 156 randomized patients, were gastrointestinal bleeding, 37; intracranial hemorrhage, 12; free-floating clot, 19; failure of anticoagulation, 29; PE, 27; prophylactic, 4; and others, 32. During a mean 12-month follow-up (range, 0-39 months), symptomatic IVC/IV thrombosis developed in five patients (6.94%) in the TrapEase group and none in the Greenfield group (P = .019). No filter migration, access-site thrombosis, misplacement, or IVC perforation occurred. Recurrent PE was suspected in one of the five patients with IVC/IV thrombosis. Overall mortality was 42.3% (66 patients), and 30-day mortality was 13.5% (21 patients: 10 TrapEase, 11 Greenfield). The study was initially designed to recruit 360 patients in both TrapEase and Greenfield filters in 2 years to demonstrate any statistical significance but was prematurely concluded due to the interim results.
  
  
  CONCLUSIONS
  A higher rate of symptomatic IVC/IV thrombosis is associated with TrapEase filter placement. However, the TrapEase filter still has a selective clinical role in the prevention of thromboembolism in selected patients who are coagulopathic. This is the first randomized prospective study comparing IVC filters since their inception in 1967.
authors.affiliation: Division of Vascular Services, Maimonides Medical Center, Brooklyn, NY 11219, USA.
authors.forename: Fred
authors.initials: F
authors.lastname: Usoh
authors.forename: Anil
authors.initials: A
authors.lastname: Hingorani
authors.forename: Enrico
authors.initials: E
authors.lastname: Ascher
authors.forename: Alexander
authors.initials: A
authors.lastname: Shiferson
authors.forename: Nirav
authors.initials: N
authors.lastname: Patel
authors.forename: Kapil
authors.initials: K
authors.lastname: Gopal
authors.forename: Natalia
authors.initials: N
authors.lastname: Marks
authors.forename: Theresa
authors.initials: T
authors.lastname: Jacob
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016009:Chi-Square Distribution; D005260:Female; D006801:Humans; D035002:Lower Extremity / Q000098:blood supply*; D008297:Male; D008875:Middle Aged; D009519:New York City; D011446:Prospective Studies; D011474:Prosthesis Design; D011655:Pulmonary Embolism / Q000209:etiology / Q000517:prevention & control*; D018570:Risk Assessment; D012307:Risk Factors; D013997:Time Factors; D016896:Treatment Outcome; D018616:Ultrasonography, Doppler, Duplex; D016306:Vena Cava Filters / Q000009:adverse effects; D020246:Venous Thrombosis / Q000150:complications / Q000000981:diagnostic imaging / Q000628:therapy*