Impact of inferior vena cava thrombosis on the prevalence of pulmonary embolism in patients with lower extremity deep vein thrombosis.

Inferior vena cava thrombosis (IVCT) is a special form of venous thromboembolism. Lower extremity deep vein thrombosis (LEDVT) is associated with an increased incidence of pulmonary embolism (PE), but the association between concomitant IVCT and PE in patients with LEDVT has not been reported. We conducted a retrospective analysis of clinical data from patients confirmed with LEDVT at the First Affiliated Hospital of Xi'an Jiaotong University. LASSO regression was used to screen important variables, and multivariable logistic regression was used to identify independently associated factors. Of the 2929 patients, 40.9% had PE and 12.8% had IVCT. Multivariable logistic regression suggested that IVCT was associated with an increased odds of PE (OR 1.42, 95% CI 1.13-1.79). Subgroup analysis showed that IVCT was associated with increased odds of PE in patients with left LEDVT (OR 2.00, 95% CI 1.50-2.67), right LEDVT (OR 2.05, 95% CI 1.20-3.50), distal LEDVT (OR 5.15, 95% CI 1.31-20.22), and proximal LEDVT (OR 1.48, 95% CI 1.19-1.86). Concomitant IVCT significantly increased the prevalence of PE in patients with LEDVT. There was no difference in PE severity or risk stratification between patients with and without IVCT. These findings could contribute to further improve the understanding of IVCT among clinicians, and optimize monitoring and management strategies of patients with LEDVT.