title: Correlation of the diameter of the left common iliac vein with the risk of lower-extremity deep venous thrombosis.
abstract: OBJECTIVE
  Compression of the left common iliac vein (CIV; LCIV) is a known risk factor for lower-extremity deep vein thrombosis (DVT). This study was performed to model the probability of DVT based on LCIV diameter and apply this to a quantitative DVT risk factor scoring system.
  
  
  METHODS
  Medical records were used to identify female patients younger than 45 years of age who were diagnosed with lower-extremity DVT (n = 21) and age-matched control subjects (n = 26) who presented to the emergency department with abdominal pain. Minimum CIV diameters were measured on computed tomography. Based on published reporting standards, 13 risk factors were scored for patients diagnosed with left-sided DVT and for control subjects. The association between vein diameter and DVT was examined by Mann-Whitney test. Odds of DVT based on vein diameter was assessed by logistic regression.
  
  
  RESULTS
  Mean minimum LCIV diameters were 4.0 mm for patients with DVT and 6.5 mm for patients without DVT (P = .001). The odds of left DVT increased by a factor of 1.68 for each millimeter decrease in LCIV diameter (odds ratio = 1.68; P = .006; 95% confidence interval, 1.16-2.43). As the risk factor score increased, the relationship between diameter and risk for DVT became stronger; identical LCIV diameters were associated wtih a higher probability of developing DVT if the risk factor score was higher.
  
  
  CONCLUSIONS
  Stenosis of the LCIV was found to be a strong independent risk factor for development of DVT. Moreover, each millimeter decrease in CIV diameter increased the odds of DVT by a factor of 1.68.
authors.affiliation: Department of Radiology, Stanford University School of Medicine, Stanford, CA 94305, USA.
authors.forename: Stephanie
authors.initials: S
authors.lastname: Carr
authors.forename: Keith
authors.initials: K
authors.lastname: Chan
authors.forename: Jarrett
authors.initials: J
authors.lastname: Rosenberg
authors.forename: William T
authors.initials: WT
authors.lastname: Kuo
authors.forename: Nishita
authors.initials: N
authors.lastname: Kothary
authors.forename: David M
authors.initials: DM
authors.lastname: Hovsepian
authors.forename: Daniel Y
authors.initials: DY
authors.lastname: Sze
authors.forename: Lawrence V
authors.initials: LV
authors.lastname: Hofmann
mesh_terms: D000293:Adolescent; D000328:Adult; D003251:Constriction, Pathologic; D005260:Female; D006801:Humans; D007084:Iliac Vein / Q000000981:diagnostic imaging*; D016015:Logistic Models; D035002:Lower Extremity / Q000098:blood supply*; D062108:May-Thurner Syndrome / Q000150:complications* / Q000000981:diagnostic imaging; D061330:Multidetector Computed Tomography; D015999:Multivariate Analysis; D016017:Odds Ratio; D010690:Phlebography / Q000379:methods*; D011237:Predictive Value of Tests; D012189:Retrospective Studies; D018570:Risk Assessment; D012307:Risk Factors; D020246:Venous Thrombosis / Q000000981:diagnostic imaging / Q000209:etiology*; D055815:Young Adult