Anand Narayan MHS, Presenter: Nothing to Disclose

Lemore Carmi MD, Abstract Co-Author: Nothing to Disclose

Siobhan McGrane MBBCh, Abstract Co-Author: Nothing to Disclose

Muneeb Ahmed MD, Abstract Co-Author: Nothing to Disclose

John Eng MD, Abstract Co-Author: Nothing to Disclose

Josef Coresh MD, PhD, Abstract Co-Author: Nothing to Disclose

Neil R. Powe MD, MPH, Abstract Co-Author: Nothing to Disclose

Michael B. Streiff MD, Abstract Co-Author: Speaker, sanofi-aventis Group Speaker, Eisai Co, Ltd Speaker, GlaxoSmithKline Speakers Bureau, sanofi-aventis Group Research Grant, Bristol-Myers Squibb Company

Kelvin Kai-Wen Hong MD, Abstract Co-Author: Speaker, Boston Scientific Corporation Consultant, SureFire, LLC

Deep venous thrombosis (DVT) has been noted to occur as much as 60% more often on the left side compared with the right side. Some have suggested that this is due to compression of the left common iliac vein (LCIV) by the right common iliac artery but there are limited data evaluating this hypothesis.We sought to determine if LCIV compression was associated with left sided DVT.

We performed a case control study of 230 consecutive patients at a tertiary center who had contrast pelvic CT prior to a diagnosis of unilateral DVT. Cases were 129 patients with left sided DVT and controls were 101 patients with right sided DVT, identified by searching radiology reports between 2004 and 2008. CT scans were read using a pilot tested reading form by two board certified radiologists blinded to case status. Iliac vein compression was measured using quantitative measures (absolute diameter of LCIV at point of maximal compression and percentage compression) and a qualitative measure of compression (none, mild, moderate, severe). Between and within reader variability and within patient variability were estimated. Logistic regression was performed with left sided DVT as the outcome and iliac vein compression as the exposure. Cutpoints of relevant compression were evaluated using splines. Means (95% CI) and odds ratios (OR) (95% CI) are presented.

Comparing left versus right DVT patients, there were no statistically significant differences in age, gender, ethnicity, history of recent surgery, cancer or immobilization. Mean LCIV diameter at the point of maximal compression was 7.8 mm (7.4, 8.2) and mean percentage compression was 34.2% (31.7, 36.6) with the LCIV as denominator and 37.1% (34.2, 40.0) with the RCIV as denominator. Overall, compressed LCIV diameter (OR 0.96 (0.88, 1.05)) and percentage compression (OR 1.00 (0.98, 1.02)) were not associated with left sided DVT, after adjusting for baseline demographics and risk factors. However 80% of patients (8/10) with greater than 67% compression were noted to have left sided DVT (OR 2.6 (0.7, 9.4)) (Figure 1).

Left common iliac vein compression greater than 67% may be associated with an elevated risk of left sided DVT however compression less than 67% was not associated with elevated risk.

Left common iliac vein compression greater than 67% noted on pelvic CT scans may be associated with an elevated risk for left DVT.

Narayan, A, Carmi, L, McGrane, S, Ahmed, M, Eng, J, Coresh, J, Powe, N, Streiff, M, Hong, K, Iliac Vein Compression as a Risk Factor for Left versus Right Deep Venous Thrombosis: A Case Control Study.  Radiological Society of North America 2010 Scientific Assembly and Annual Meeting, November 28 - December 3, 2010 ,Chicago IL. http://archive.rsna.org/2010/9003270.html