Caval-Iliac Vein Angle and Risk of Pulmonary Embolism in Patients with Right-Sided Deep Vein Thrombosis

To investigate the risk factors for pulmonary embolism (PE) and evaluate the hypothesis that an increased caval-iliac vein angle (CVA) is associated with a decreased risk of PE in patients with right-sided deep venous thrombosis (DVT).

This retrospective study analyzed 163 patients with right-sided DVT who underwent computed tomography (CT) venography between 2017 and 2024. Demographic, clinical, and radiographic data were collected. Univariate analysis followed by multivariate analysis determined the odds ratio (OR) with a 95% confidence interval (CI). Correlations between CVA and PE on a continuous scale were evaluated using restricted cubic splines.

In total, 76 patients (46.6%) were diagnosed with PE, while 87 (53.4%) were not. Patients with PE were found to have a higher prevalence of heart failure (adjusted OR, 4.16; 95% CI, 1.40-12.39; P = .011), autoimmune diseases (adjusted OR, 3.86; 95% CI, 1.06-14.05; P = .040), and a smaller CVA (adjusted OR, 0.89; 95% CI, 0.85-0.94; P < .001). Following propensity score matching, the inverse relationship between CVA (adjusted OR, 0.91; 95% CI, 0.86-0.95; P < .001) and PE persisted. Restricted cubic spline analysis revealed a greater CVA consistently correlated with a lower risk of PE (nonlinear P = .038). Moreover, CVA was a protective factor against symptomatic PE when the CVA was >15.75°.

Heart failure and autoimmune diseases were associated with an increased risk of PE, whereas an increased CVA was consistently linked with a decreased risk. A CVA greater than 15.75° serves potentially as a protective factor against symptomatic PE.