Objective To analyze the relationship between venous thrombosis and pulmonary embolism (PE) at different sites through the results of venous ultrasonography of lower extremities, and provide a reference for the evaluation of PE patients and treatment options.

Methods A total of 312 patients treated in the Department of Cardiology, Shanghai Chest Hospital, Shanghai Jiao Tong University from January 2018 to December 2019 were analyzed retrospectively. All patients were examined by CT pulmonary angiography and lower extremity vein ultrasonography. According to the results of examination, they were divided into PE group and non-PE group. Univariate and multivariate correlation analysis was made according to the difference of ultrasound results and medical history data.

Results There were significant differences in sex constituent ratio, age, complication of lung cancer, occurrence and location of venous thrombosis of lower extremities between the two groups (P < 0.05). The results of multivariate Logistic regression analysis showed that there was a significant correlation between lower limb venous thrombosis and the occurrence of pulmonary embolism (OR=8.344, 95% CI 4.867-14.304). Intermuscular vein thrombosis (OR=2.996, 95%CI 1.630-5.509), popliteal vein thrombosis (OR=5.536, 95%CI 1.646-18.623) and posterior tibial vein thrombosis (OR=6.685, 95%CI 1.789-24.990) were significantly associated with higher incidence of PE.

Conclusions The risk of PE is significantly increased in patients with lower limb venous thrombosis, and intermuscular vein thrombosis, popliteal vein thrombosis and posterior tibial vein thrombosis are independent risk factors for PE.