<h4>Background</h4>The serum levels of soluble CD40 ligand (sCD40L), cytokine ligand 3 (CCL3), and N-terminal pro-brain natriuretic peptide (NT-proBNP) are closely associated with heart failure (HF).<h4>Objective</h4>This study evaluated the predictive value of serum sCD40L, CCL3, and NT-proBNP levels for lower limb venous thrombosis (LLVT) in elderly patients with HF.<h4>Methods</h4>A total of 200 patients with HF were retrospectively included and equally divided into thrombus and non-thrombus groups based on lower limb vein ultrasound findings. The gene discussed is CCL3; the disease is hydrops fetalis.