title: Common iliac vein stenosis and risk of symptomatic pulmonary embolism: an inverse correlation.
abstract: OBJECTIVE
  To test the hypothesis that a common iliac vein (CIV) stenosis may impair embolization of a large deep venous thrombosis (DVT) to the lungs, decreasing the incidence of a symptomatic pulmonary embolism (PE).
  
  
  METHODS
  Between January 2002 and August 2007, 75 patients diagnosed with unilateral DVT were included in a single-institution case-control study. Minimum CIV diameters were measured 1 cm below the inferior vena cava (IVC) bifurcation on computed tomography (CT) images. A significant stenosis in the CIV ipsilateral to the DVT was defined as having either a diameter 4 mm or less or a greater than 70% reduction in lumen diameter. A symptomatic PE was defined as having symptoms and imaging findings consistent with a PE. The odds of symptomatic PE versus CIV stenosis were assessed using logistic regression models. The associations between thrombus location, stenosis, and symptomatic PE were assessed using a stratified analysis.
  
  
  RESULTS
  Of 75 subjects, 49 (65%) presented with symptomatic PE. There were 17 (23%) subjects with a venous lumen 4 mm or less and 12 (16%) subjects with a greater than 70% stenosis. CIV stenosis of 4 mm or less resulted in a decreased odds of a symptomatic PE compared with a lumen greater than 4 mm (odds ratio [OR] 0.17, P = .011), whereas a greater than 70% stenosis increased the odds of DVT involving the CIV (OR 7.1, P = .047).
  
  
  CONCLUSIONS
  Among patients with unilateral DVT, those with an ipsilateral CIV lumen of 4 mm or less have an 83% lower risk of developing symptomatic PE compared with patients with a CIV lumen greater than 4 mm.
authors.affiliation: Department of Radiology, Division of Interventional Radiology, Stanford University School of Medicine, 300 Pasteur Drive, Suite H-3630, Stanford, CA 94305-5642, USA. ktc@stanford.edu
authors.forename: Keith T
authors.initials: KT
authors.lastname: Chan
authors.forename: Rita A
authors.initials: RA
authors.lastname: Popat
authors.forename: Daniel Y
authors.initials: DY
authors.lastname: Sze
authors.forename: William T
authors.initials: WT
authors.lastname: Kuo
authors.forename: Nishita
authors.initials: N
authors.lastname: Kothary
authors.forename: John D
authors.initials: JD
authors.lastname: Louie
authors.forename: David M
authors.initials: DM
authors.lastname: Hovsepian
authors.forename: Gloria L
authors.initials: GL
authors.lastname: Hwang
authors.forename: Lawrence V
authors.initials: LV
authors.lastname: Hofmann
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002140:California / Q000453:epidemiology; D015897:Comorbidity; D005260:Female; D006801:Humans; D007084:Iliac Vein / Q000000981:diagnostic imaging*; D015994:Incidence; D008297:Male; D011655:Pulmonary Embolism / Q000000981:diagnostic imaging* / Q000453:epidemiology*; D011859:Radiography; D018570:Risk Assessment / Q000379:methods; D012307:Risk Factors; D013223:Statistics as Topic; D014689:Venous Insufficiency / Q000000981:diagnostic imaging* / Q000453:epidemiology*; D020246:Venous Thrombosis / Q000000981:diagnostic imaging* / Q000453:epidemiology*; D055815:Young Adult