title: Transcatheter manipulation of asymmetrically opened titanium Greenfield filters.
abstract: OBJECTIVE
  The problem of asymmetric opening of the modified hook titanium Greenfield inferior vena cava filter necessitating transcatheter manipulation was evaluated in a retrospective study.
  
  
  METHODS
  Titanium Greenfield filters were placed in 166 patients over a 36-month period. The radiographic reports of all patients were reviewed to identify cases in which the filter failed to open symmetrically after deployment and catheter or wire manipulation of the filter was performed. The reports and angiograms from these patients were reviewed with respect to the circumstances surrounding filter placement and methods to achieve more symmetric opening.
  
  
  RESULTS
  Transcatheter manipulation of asymmetrically opened filters was performed in 15 of 166 cases (9%). In 12 of these patients, acceptable and uneventful opening of the filter was achieved with a guide wire, pigtail catheter, or occlusion balloon catheter. In one case manipulation only partly improved orientation of the limbs, while in another case successful manipulation was complicated by distal migration. In the final case, the asymmetric filter covered only part of the lumen of the vena cava despite manipulations and a second filter was placed for optimal caval interruption. No specific cause for incomplete expansion was identified in any case.
  
  
  CONCLUSIONS
  Marked asymmetry in opening of the modified hook titanium Greenfield filter that warrants manipulation occurs infrequently, but recognition and proper management may be important to ensure optimal caval interruption.
authors.affiliation: Department of Radiology, University of California at San Diego 92103.
authors.forename: B S
authors.initials: BS
authors.lastname: Moore
authors.forename: K
authors.initials: K
authors.lastname: Valji
authors.forename: A C
authors.initials: AC
authors.lastname: Roberts
authors.forename: J J
authors.initials: JJ
authors.lastname: Bookstein
mesh_terms: D002405:Catheterization, Central Venous; D006801:Humans; D011859:Radiography; D014025:Titanium; D016306:Vena Cava Filters; D014682:Vena Cava, Inferior / Q000000981:diagnostic imaging
chemical_list: D014025:Titanium