Can Routine Investigation for Occult Pulmonary Embolism Be Justified in Patients with Deep Vein Thrombosis?

Purpose: This study aims to investigate whether routine screening for silent pulmonary embolism (PE) can be justified in patients with deep vein thrombosis (DVT). Materials and Methods: We retrospectively analyzed the medical records of 201 patients with lower-extremity DVT admitted to the vascular surgery department of a single tertiary university center between 2019 and 2023. All patients underwent clinical evaluation, basic laboratory exams, a whole-leg colored duplex ultrasound, and a computed tomography pulmonary angiography (CTPA), to screen for an occult, underlying PE. Results: The overall incidence of silent PE was 48.8%. The median admission D-dimer level was significantly higher in patients with silent PE than in those without PE (9.60 vs. 5.51 mg/L, P=0.001). A D-dimer value ≥5.14 mg/L was discriminant for predicting silent PE, with a sensitivity of 68.2% and a specificity of 59.3%. Silent PE was significantly more common on the right side, with the embolus located at the main pulmonary, lobar, segmental, and subsegmental arteries in 29.6%, 32.7%, 20.4%, and 17.3%, respectively. A higher incidence of occult PE was observed in patients with iliofemoral DVT (P=0.037), particularly when the thrombus extended to the inferior vena cava (P=0.003). Moreover, iliofemoral DVT was associated with a larger size and a more proximal location of the embolus (P=0.041). Multivariate logistic regression showed that male sex (odds ratio [OR]=2.46, 95% confidence interval [CI]: 1.39-3.53; P=0.026), cancer (OR=2.76, 95% CI: 1.45-4.07; P=0.017), previous venous thromboembolism (VTE) history (OR=2.67, 95% CI: 1.33-4.01; P=0.022), D-dimer value ≥5.14 mg/L (OR=2.24, 95% CI: 1.10-3.38; P=0.033), iliofemoral DVT (OR=2.13, 95% CI: 1.19-3.07; P=0.041), and thrombus extension to the IVC (OR=2.95, 95% CI: 1.43-4.47; P=0.009) served as independent predictors for silent PE. Conclusion: A high incidence of silent PE was observed in patients with lower-extremity DVT. Screening of patients with DVT who have the aforementioned predictive risk factors using CTPA for silent PE may be needed and justified for the efficient management of VTE and its long-term complications.