Formation of pulmonary vein stump thrombus after anatomical lung resection and anticoagulant therapy

OBJECTIVE: It has recently been suggested that the formation of pulmonary vein stump thrombus (PVST) after anatomical lung resection is an underlying cause of arterial thromboembolism including cerebrovascular infarction. This study aimed to investigate the incidence and risk factors of PVST and to evaluate the efficacy and safety of anticoagulant therapy for PVST. METHODS: Patients who underwent anatomical lung resection for malignant lung tumors were eligible for inclusion in this study. Chest contrast-enhanced (CE) computed tomography (CT) was performed after surgery to detect PVST. If PVST was observed, patients received anticoagulant therapy. The size of the PVST was followed-up by repeated chest CE-CT. RESULTS: In total, 176 patients were enrolled in this study. Chest CE-CT was performed on postoperative day 1-13 (median, postoperative day 6). PVST was detected in 22 (12.5%) patients. The median size of PVST was 9.5 (4.1-33.4) mm. Thrombus was most commonly observed in patients who underwent left upper lobectomy (9/36, 25.0%). Hypertension, dyslipidemia, arteriosclerosis, and arrhythmia were not associated with PVST formation. Anticoagulant therapy was administered to all 22 patients with PVST until the PVST disappeared. The median duration between the detection and disappearance of PVST was 77 days (range: 6-146 days). During the period between the detection and disappearance of PVST, cerebrovascular infarction or arterial thromboembolic events were not observed. CONCLUSIONS: Postoperative PVST is commonly observed, especially in patients who undergo left upper lobectomy. Anticoagulant therapy for PVST was safely introduced and was efficient to improve PVST without subsequent arterial thromboembolic events.