Left iliac vein compression is not associated with infrainguinal deep venous thrombosis but is associated with iliac vein involvement.

The purpose of this study was to investigate whether left iliac vein (LIV) compression had similar correlation with the risk of left iliac deep venous thrombosis (DVT; iliac vein involvement) and infrainguinal DVT (without iliac vein involvement). A retrospective analysis of records and enhanced computed tomography images was conducted of 278 patients with left-sided DVT (iliac DVT, 228 patients; infrainguinal DVT, 50 patients) and 232 control patients without DVT on either side. The influences of LIV compression on the risk of left iliac DVT and infrainguinal DVT were investigated using logistic regression analysis. Mean percentage compression of the LIV in left iliac DVT (74.64% ± 0.99%) patients was significantly higher than in non-DVT patients (53.42% ± 1.49%; P < .01). However, mean percentage compression of the LIV in left infrainguinal DVT patients (45.37% ± 2.71%) was significantly lower than in non-DVT patients (53.42% ± 1.49%; P < .01). LIV compression was associated with increased odds of left iliac DVT (odds ratio, 1.88; 95% confidence interval, 1.64-2.15; P < .01) for each 10% increase in percentage compression of the LIV. However, LIV compression was not associated with increased odds of infrainguinal DVT (odds ratio, 0.89; 95% confidence interval, 0.76-1.03; P = .126). Left iliac DVT patients had more severe LIV compression than left infrainguinal DVT patients did. LIV compression was not associated with development of left infrainguinal DVT, but it did correlate with the presence of left-sided DVT with iliac vein involvement.

Chen D ，Chen F ，Li MF ，Huang JG ，Tang XH ，Zhou WM ... -  《-》

Correlation of the diameter of the left common iliac vein with the risk of lower-extremity deep venous thrombosis.

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. 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. 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. 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.

Carr S ，Chan K ，Rosenberg J ，Kuo WT ，Kothary N ，Hovsepian DM ，Sze DY ，Hofmann LV ... -  《-》

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

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). 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. 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). 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. http://radiology.rsna.org/lookup/suppl/doi:10.1148/radiol.12111580/-/DC1.

Narayan A ，Eng J ，Carmi L ，McGrane S ，Ahmed M ，Sharrett AR ，Streiff M ，Coresh J ，Powe N ，Hong K ... -  《-》

Severe compression of left iliac vein is a protective factor for the risk of inferior vena cava thrombosis.

The purpose of this study is to evaluate the association between left iliac vein (LIV) compression and inferior vena cava thrombosis (IVCT) in patients with LIV involvement of deep vein thrombosis (DVT). A total of 263 consecutive patients with DVT were reviewed retrospectively and divided into a group with IVCT and a group without IVCT. The influences of LIV smallest diameter and percentage compression on the risk of IVCT were investigated using logistic regression analysis. The mean age of patients with IVCT was significantly younger than that of patients without IVCT (55.5 ± 1.8 vs 62.7 ± 1.1; P = .001). The percentage of provoked DVT in patients with IVCT was higher than that in patients without IVCT (67.1% vs 48.2%; P = .01). The smallest diameter of the LIV in patients with ICVT was larger than that in patients without IVCT (4.1 ± 0.3 vs 2.5 ± 0.2; P < .001). The mean percentage compression of LIV in patients with IVCT was significantly lower than that in patients without IVCT (63.5 ± 2.2 vs 74.3 ± 1.3; P < .001). Age was associated with a decreased odds of ICVT (odds ratio [OR], 0.965; 95% confidence interval [CI], 0.965-0.985; P = .001). Provoked DVT was associated with an increased odds of ICVT (OR, 2.011; 95% CI, 1.070-3.782; P = .03). LIV compression was associated with a decreased odds of ICVT for each 1-mm decrease in smallest diameter of the LIV (OR, 0.717; 95% CI, 0.627-0.820; P < .001), and for each 10% increase in percentage compression of the LIV (OR, 0.715; 95% CI, 0.612-0.835; P < .001). For LIV involvement in patients with DVT, patients without IVCT had more severe LIV compression than patients with IVCT. Severe LIV compression may be a protective factor for the risk of IVCT.

Liu XR ，Zhou W ，Chen F 《-》

Incidence and Risk Factors of Deep Venous Thrombosis in Asymptomatic Iliac Vein Compression: A Prospective Cohort Study.

Wu MK ，Luo XY ，Zhang FX 《-》