title: Technical factors affecting the accuracy of bedside IVC filter placement using intravascular ultrasound.
abstract: OBJECTIVE
  To compare the accuracy of inferior vena cava (IVC) filter placement using a bedside technique guided by intravascular ultrasound (IVUS) with a concurrent experience of filter deployment with fluoroscopic venogram imaging.
  
  
  METHODS
  From November 2006 to December 2009, 195 consecutive IVC filters were placed to prevent pulmonary embolism in 120 high-risk patients without lower limb deep vein thrombosis (DVT) and 75 patients with DVT and anticoagulation contraindications. Filter insertion techniques included bedside IVUS-guided (n = 97) and fluoroscopic-guided (n = 98) procedures. Before mid-2008, 2 bedside IVUS-guided protocols were used evolving from a single-puncture, pullback technique (n = 48), in which the measured distance from the venous access site to the IVC landing zone then allowed a calibrated reinsertion of a 7F delivery sheath and filter deployment. After mid-2008, a single puncture 8F sheath technique (n = 48) using IVUS to position the delivery sheath tip within the IVC landing zone without catheter or sheath measurement or reinsertion was used. Venous access was via the right femoral (84 IVUS and 56 fluoroscopy), left femoral (10 IVUS and 16 fluoroscopy), or right internal jugular vein (3 IVUS and 26 fluoroscopy). The 3 filter insertion techniques were compared for "optimal" IVC placement defined as the filter positioning between L1 and L4 vertebrae with tilt <15° based on postprocedure abdominal x-rays or venography.
  
  
  RESULTS
  Filter malposition occurred with 6% (6 of 97) bedside IVUS-guided procedures with no malpositions during fluoroscopic imaging. Malposition was lower with the evolved sheath (4%, 2 of 48) compared with the earlier pullback (8%, 4 of 48) insertion technique (P = .03). The incidence of the filter malposition during IVUS-guided deployment was highest using left femoral access (4 of 10) compared with right femoral (2 of 84) or internal jugular (0 of 3) vein access (P < .01). Filter tilt occurred more after IVUS-guided procedure (10 of 97) than fluoroscopic procedure (3 of 98; P = .05) and was most frequent for left femoral access (5 of 10 IVUS and 1 of 16 fluoroscopy; P < .01) and was not related to filter type (P = .13).
  
  
  CONCLUSIONS
  Our current bedside IVUS-guided IVC filter technique using a single venous puncture and single sheath positioning has improved the placement accuracy. Left femoral venous access should be avoided to minimize the occurrence of filter malpositioning and tilt.
authors.affiliation: Division of Vascular and Endovascular Surgery, College of Medicine, University of South Florida, Tampa, FL, USA.
authors.forename: Kelley
authors.initials: K
authors.lastname: Hodgkiss-Harlow
authors.forename: Martin R
authors.initials: MR
authors.lastname: Back
authors.forename: Robert
authors.initials: R
authors.lastname: Brumberg
authors.forename: Paul
authors.initials: P
authors.lastname: Armstrong
authors.forename: Murray
authors.initials: M
authors.lastname: Shames
authors.forename: Brad
authors.initials: B
authors.lastname: Johnson
authors.forename: Dennis F
authors.initials: DF
authors.lastname: Bandyk
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002404:Catheterization / Q000295:instrumentation*; D002648:Child; D005260:Female; D005268:Femoral Vein / Q000000981:diagnostic imaging; D005431:Florida; D005471:Fluoroscopy; D006801:Humans; D007601:Jugular Veins / Q000000981:diagnostic imaging; D008297:Male; D008875:Middle Aged; D010690:Phlebography; D019095:Point-of-Care Systems; D011655:Pulmonary Embolism / Q000209:etiology / Q000517:prevention & control*; D011677:Punctures; D015641:Radiography, Interventional / Q000379:methods; D012189:Retrospective Studies; D013997:Time Factors; D016896:Treatment Outcome; D018084:Ultrasonography, Interventional; D016306:Vena Cava Filters / Q000009:adverse effects; D014682:Vena Cava, Inferior / Q000000981:diagnostic imaging*; D020246:Venous Thrombosis / Q000150:complications / Q000000981:diagnostic imaging / Q000628:therapy*; D055815:Young Adult