title: Limb asymmetry in titanium Greenfield filters: clinically significant?
abstract: OBJECTIVE
  The purpose of this study was to determine the outcomes for patients with titanium Greenfield vena caval filters (TGFs) and, in particular, to evaluate the effect of filter leg distribution on recurrent pulmonary embolism (PE) and caval occlusion.
  
  
  METHODS
  Physical examination, abdominal plain films, and duplex ultrasound examinations of the inferior vena cava and lower extremities were obtained annually and recorded in a Filter Database.
  
  
  RESULTS
  Seven hundred eighty-three TGFs have been placed since 1989. Follow-up was available for 373 patients, or 65% of the surviving patients, over 1 to 84 months (mean, 33 months). Asymmetry was identified in 42 placements (5%), and 35 of these patients had at least one follow-up examination. The overall incidence of recurrent PE was 3.2% (12 of 373), whereas the caval patency rate was 97.8% (265 of 271). These outcomes were not significantly different for patients who had asymmetric filters (p = 0.1 and 0.18, respectively).
  
  
  CONCLUSIONS
  Filter leg distribution does not appear to be associated with an increased incidence of recurrent PE or caval occlusion. These data support earlier in vitro findings. The long-term results with the TGF are comparable with the results of the original stainless steel Greenfield filter.
authors.affiliation: Department of Surgery, University of Michigan Hospitals, USA.
authors.forename: L J
authors.initials: LJ
authors.lastname: Greenfield
authors.forename: M C
authors.initials: MC
authors.lastname: Proctor
authors.forename: K J
authors.initials: KJ
authors.lastname: Cho
authors.forename: T W
authors.initials: TW
authors.lastname: Wakefield
mesh_terms: D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D011655:Pulmonary Embolism / Q000000981:diagnostic imaging / Q000517:prevention & control*; D011859:Radiography; D012008:Recurrence; D014025:Titanium; D014654:Vascular Patency; D016306:Vena Cava Filters / Q000009:adverse effects; D014684:Venae Cavae / Q000000981:diagnostic imaging
chemical_list: D014025:Titanium