Iliac Vein Compression: A Protective Mechanism Against Symptomatic Pulmonary Embolism Following Lower Extremities Deep Vein Thrombosis

ObjectiveTo investigate the protective effect of iliac vein compression in patients with symptomatic pulmonary embolism (PE) of lower extremity deep vein thrombosis (LEDVT). MethodsThe clinical data of 82 patients with unilateral LEDVT including computed tomography of pulmonary angiogram (CTPA) and CT image data of common iliac vein from February 2020 to April 2023 were retrospectively analyzed. The patients were divided into two groups according to the presence or absence of PE. Univariate and multivariate logistic regression were used to analyze the risk factors of symptomatic PE in patients with LEDVT. The predictive value of severity of iliac vein compression for symptomatic PE with different measurements were further compared with receiver operating characteristics curve. ResultsUnivariate analysis showed that compression > 50% (OR = 0.19,95% CI = 0.07-0.51, P = .001) was a protective factor for symptomatic PE. Multivariate analysis showed that compression > 50% (OR = 0.21,95% CI = 0.07-0.64, P = .006) was a protective factor for symptomatic PE. Different compression measurements were compared. With affected caudal diameter as denominator, the area under curve (AUC) was 0.729, the cut-off value was 0.52, the sensitivity was 70.6%, and the specificity was 71.0%. Patent contralateral diameter as denominator, the AUC was 0.729, the cut-off value was 0.49, the sensitivity was 54.9%, and the specificity was 87.1%. ConclusionsIn patients with LEDVT, iliac vein compression greater than 50% is a protective factor for symptomatic PE. A larger sample is needed to determine the protective effect of iliac vein compression.