Subclinical venous thromboembolism after pulmonary resection for lung cancer: an observational study

Abstract
Background
Subclinical venous thromboembolism is a hidden pathology which may present with catastrophic consequences if not diagnosed at an early stage. This study was undertaken to estimate the occurrence and associated risk factors of subclinical deep vein thrombosis after lung resection for lung cancer patients. A prospective observational cohort study was performed in a tertiary cardiothoracic surgery center. One hundred fifty patients who underwent different types of lung resection for lung cancer were enrolled. Caprini’s risk score was assessed in all patients. All patients received prophylactic stockings and anticoagulants. On the 5th postoperative day, a duplex venous ultrasound of bilateral lower limbs was performed on every asymptomatic patient.

Results
Out of 150 patients enrolled in the study, 147 patients completed the study. Four patients (2.72%) developed subclinical deep vein thrombosis. The patients were divided into 2 groups: group 1 (n = 143) post-lung resection and no DVT and group 2 (n = 4) with post-lung resection subclinical DVT. No patient developed postoperative clinical DVT. The incidence was found to be highest in the group of individuals who had a longer stay in the ICU (odds ratio 37.9) (p = 0.04). Among the various pathologies, the incidence was higher in patients who received preoperative chemotherapy (odds ratio 21.9) (p = 0.001). One patient in the subclinical DVT group (25%) died, while no mortality was observed in the no DVT group.

Conclusions
The incidence of subclinical deep vein thrombosis is low in the postoperative period among patients undergoing lung resection for lung cancer if appropriate prophylactic measures are applied. However, patients receiving preoperative chemotherapy and those with longer periods of immobilization are at a higher risk of developing postoperative DVT despite anticoagulant prophylaxis. Due to the sample size and design limitations, the mentioned risk factors could be associated with DVT not a cause of DVT. It might be justified to screen these high-risk groups to detect subclinical DVT to allow for post-discharge prophylaxis.