Iliac vein compression as risk factor for left- versus right-sided deep venous thrombosis: case-control study

Radiology. 2012 Dec;265(3):949-57. doi: 10.1148/radiol.12111580.


Purpose: To determine if compression of the left common iliac vein (LCIV) by the right common iliac artery is associated with left-sided deep venous thrombosis (DVT).

Materials and methods: This institutional review board-approved case-control study was performed in a cohort of 230 consecutive patients (94 men, 136 women; mean age, 57.5 years; range, 10-94 years) at one institution who had undergone contrast material-enhanced computed tomography of the pelvis prior to a diagnosis of unilateral DVT. Demographic data and information on risk factors were collected. Two board-certified radiologists determined iliac vein compression by using quantitative measures of percentage compression {[1 minus (LCIV diameter at point of maximal compression/distal right common iliac vein diameter)] times 100%}, as well as qualitative measures (none, mild, moderate, severe), with estimates of measurement variability. Logistic regression analysis was performed (independent variable, left vs right DVT; dependent variable, iliac vein compression). Cutpoints of relevant compression were evaluated by using splines. Means (with 95% confidence intervals [CIs]) and odds ratios (ORs) (and 95% CIs) of left DVT per 1% increase in percentage compression were calculated.

Results: Patients with right DVT were more likely than those with left DVT to have a history of pulmonary embolism. Overall, in all study patients, mean percentage compression was 36.6%, 66 (29.7%) of 222 had greater than 50% compression, and 16 (7.2%) had greater than 70% compression. At most levels of compression, increasing compression was not associated with left DVT (adjusted ORs, 1.00, 0.99, 1.02) but above 70%, LCIV compression may be associated with left DVT (adjusted ORs, 3.03, 0.91, 10.15).

Conclusion: Increasing levels of percentage compression were not associated with left-sided DVT up to 70%; however, greater than 70% compression may be associated with left DVT.

Supplemental material:

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Aged, 80 and over
  • Case-Control Studies
  • Chi-Square Distribution
  • Child
  • Contrast Media
  • Female
  • Humans
  • Iohexol
  • Logistic Models
  • Male
  • May-Thurner Syndrome / complications*
  • May-Thurner Syndrome / diagnostic imaging*
  • Middle Aged
  • Pulmonary Embolism / etiology
  • Risk Factors
  • Tomography, X-Ray Computed*
  • Triiodobenzoic Acids
  • Venous Thrombosis / diagnostic imaging*
  • Venous Thrombosis / etiology*


  • Contrast Media
  • Triiodobenzoic Acids
  • Iohexol
  • iodixanol