title: Suprarenal filter placement.
abstract: OBJECTIVE
  This study was undertaken to determine the clinical outcomes for patients with Greenfield filters placed in the suprarenal (SR) inferior vena cava (IVC).
  
  
  METHODS
  We collected data prospectively from annual follow-up evaluations of patients with filters. Patients underwent venous color-flow duplex examinations of the IVC and lower extremities, abdominal radiographs, and physical assessment. The outcomes for those patients with filters in the SR IVC were compared with the outcomes previously reported and with the outcomes for patients with filters in the infrarenal cava.
  
  
  RESULTS
  SR placement accounted for 7.6% (148/1932) of all filter placements. Follow-up data were available for 73 placements, or 49%. No cases of renal dysfunction were related to filter placement. The rate of recurrent pulmonary embolism (PE) was 8%, and the rate of long-term caval occlusion was 2.7%. These rates did not differ statistically from the rates for patients with infrarenal filters (P > .05). Male patients tended to be older by 15 years, to have more recurrent PE, and to experience more filter migration (6 vs 2 mm). Failure of SR filters to prevent PE was associated statistically with the primary indication for placement. Recurrent PE was the indication in 5 of 6 patients who sustained PE after SR filter placement (P = .007). Filter limb fracture was seen only with the stainless-steel Greenfield filter.
  
  
  CONCLUSIONS
  Greenfield filters placed above the renal vein provide protection from PE with a minimal risk of occlusion. Twenty-five years of experience with Greenfield filters shows that they are safe and effective both in young female patients of child-bearing potential and in all patients with appropriate indications for SR placement.
authors.affiliation: Department of Surgery, University of Michigan Hospitals, Ann Arbor, USA.
authors.forename: L J
authors.initials: LJ
authors.lastname: Greenfield
authors.forename: M C
authors.initials: MC
authors.lastname: Proctor
mesh_terms: D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D011475:Prosthesis Failure; D011655:Pulmonary Embolism / Q000517:prevention & control*; D012008:Recurrence; D012082:Renal Veins; D013193:Stainless Steel; D016896:Treatment Outcome; D016306:Vena Cava Filters / Q000009:adverse effects
chemical_list: D013193:Stainless Steel