title: Stenting of chronically obstructed inferior vena cava filters.
abstract: OBJECTIVE
  A protective inferior vena cava (IVC) filter may later be incorporated into a chronic postthrombotic ilio-caval obstruction (occlusive, requiring recanalization, or nonocclusive). This study aims to assess the safety and stent-related outcome following stenting across an obstructed filter.
  
  
  METHODS
  From 1997 to 2009, 708 limbs had stenting for postthrombotic ilio-caval outflow obstruction (occlusion in 121 limbs). In 25 patients, an IVC filter was obstructed (Group X). The site was crossed by a guidewire and balloon dilated. The filter was markedly displaced sidewise or remodeled. A stent was placed across the IVC filter and redilated. In 28 other patients, the cephalad stenting terminated below a patent IVC filter (Group B). The remaining 655 patients had no previous IVC filter placement (Group no IVC filter present [NF]). The patients were followed to assess patency. The types of reintervention were noted.
  
  
  RESULTS
  The stenting maneuver through a variety of previously inserted IVC filters was safely performed without an apparent tear of the IVC, no clinical bleeding or abdominal symptoms, or pulmonary embolism. Mortality was nil; morbidity minimal. The primary and secondary cumulative patency rates at 54 months for limbs with postthrombotic obstruction were with and without IVC filter (38% and 40%; P = .1701 and 79% and 86%; P = .1947, respectively), and for limbs with stenting across the filter (Group X) and stent termination below the filter (Group B; 32% and 42%; P = .3064 and 75% and 84%; P = .2788, respectively), not statistically different. When Group X alone was compared with Group NF, the secondary patency rate was, however, significantly lower (75% vs 86%; P = .0453), suggesting that crossing of the stent was associated with reduced patency. Occlusive postthrombotic disease requiring recanalization was more frequent in Group X than in Group B and Group NF (68%, 25%, and 15%, respectively; P = .004). A comparison was therefore performed only between limbs stented for recanalized occlusions with (n = 23) and without IVC filters (n = 92) showing no difference (cumulative primary and secondary patency rates 30% and 35%; P = .9678 and 71% and 73%; P = .9319, respectively). Multiple logistic regression analysis also supported a significant association between patency rate and occlusive disease (odds ratio, 6.9; 95% confidence interval, 3.4-13.9; P < .0001), but not between patency rate and presence of an IVC filter (P = .5552).
  
  
  CONCLUSIONS
  Stenting across an obstructed IVC filter is safe. It appears that patency is not influenced by the fact that an IVC filter is crossed by a stent, but is related to the severity of postthrombotic disease (occlusive or nonocclusive obstruction) and the associated recanalization procedure.
authors.affiliation: River Oaks Hospital, Flowood, MS 39232, USA. neglenmd@earthlink.net
authors.forename: Peter
authors.initials: P
authors.lastname: Neglén
authors.forename: Mathew
authors.initials: M
authors.lastname: Oglesbee
authors.forename: Jake
authors.initials: J
authors.lastname: Olivier
authors.forename: Seshadri
authors.initials: S
authors.lastname: Raju
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002404:Catheterization / Q000295:instrumentation*; D002908:Chronic Disease; D057510:Endovascular Procedures / Q000295:instrumentation*; D005260:Female; D005268:Femoral Vein / Q000000981:diagnostic imaging / Q000503:physiopathology; D006801:Humans; D007084:Iliac Vein / Q000000981:diagnostic imaging / Q000503:physiopathology; D053208:Kaplan-Meier Estimate; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D010690:Phlebography; D011475:Prosthesis Failure; D019233:Retreatment; D012189:Retrospective Studies; D018570:Risk Assessment; D012307:Risk Factors; D015607:Stents; D013997:Time Factors; D016896:Treatment Outcome; D014654:Vascular Patency; D016306:Vena Cava Filters; D014682:Vena Cava, Inferior / Q000000981:diagnostic imaging / Q000503:physiopathology; D020246:Venous Thrombosis / Q000503:physiopathology / Q000628:therapy*; D055815:Young Adult