Thrombus Removal by Acute-phase Endovascular Reperfusion Therapy to Treat Cerebral Embolism Caused by Thrombus in the Pulmonary Vein Stump after Left Upper Pulmonary Lobectomy: Case Report

Abstract

cerebral embolism of unknown cause. 3) Cerebral embolism caused by thrombus formed in the pulmonary vein stump after pulmonary lobectomy is a rare complication, and the concept has only been recognized in recent years. 2) Reports from authors specializing in the cerebrovascular system have not been seen previously. We describe herein the first description of experience with a case in which thrombus removal was performed by acute-phase endovascular reper-fusion therapy to treat cerebral embolism attributed to thrombus formation in a pulmonary vein stump after left upper lobectomy. Case Report I. History and examination The patient was a 58-year-old man who smoked 20 ciga-rettes a day for 23 years. He had previously undergone crani-otomy and clipping to treat an unruptured cerebral aneurysm at the bifurcation of posterior communicating artery and left internal carotid artery at 55 years old. Medical examination showed an abnormal shadow in the left lung, and a 17-mm lesion was observed in the left upper lobe on chest computed tomography (CT). Transbronchial lung biopsy determined this to be adenocarcinoma. The patient subsequently under-went left upper lobectomy with video-assisted thoracoscopic surgery, with the left upper pulmonary vein cut off using a linear stapler at that time. Lymph node metastasis was not observed and the patient was determined to have stage IA early lung cancer. Although no issues were seen during the postoperative clinical course, the patient developed sudden disturbance of consciousness, right hemiplegia, and total aphasia 2 days postoperatively while in the hospital ward. Body temperature was 36.8°C, blood pressure was 122/78 mmHg, and heart rate was 84 beats/min without atrial fibril-lation. Blood test findings showed no abnormalities in the complete blood count, with a prothrombin time of 12.9 s (normal range 10–12), activated partial thromboplastin time of 39.6 s (normal range 24–39), fibrinogen level of 605 mg/dl (normal range 200–400), D-dimer level of 1.89 µg/ml (normal range 0–0.99), and fibrin degradation product level of 6 µg/ml (normal range 0–5), demonstrating only mild activa-tion of the coagulation system. Cardiogenic cerebral embo-lism was considered among the differential diagnoses, but brain natriuretic peptide level was 7.0 pg/ml (normal range 0–18.4), which was within the normal range. Protein C, pro-tein S, and antithrombin III levels were likewise within the normal ranges. The patient was negative for lupus Thrombus formation in a pulmonary vein stump after pulmonary lobectomy is extremely rare, but can trigger cerebral embolism of unknown cause. We encountered a case of cerebral embolism in a 58-year-old man 2 days after left upper lobectomy. Since intravenous adminis-tration of recombinant tissue plasminogen activator was contraindicated, thrombus removal by endovascular reperfusion therapy was performed. Cerebral angiogra-phy showed left internal carotid artery occlusion. Thrombus removal using a retrieval device was per-formed and complete recanalization of the left internal carotid artery was obtained. Although blood abnormali-ties or arrhythmia such as atrial fibrillation were not observed, thrombus in the left upper pulmonary vein stump was detected with contrast-enhanced computed tomography of the body trunk, which was therefore considered as the source of cerebral embolism. The patient is continuing on anticoagulant therapy to prevent embolism recurrence caused by thrombus for-mation in the pulmonary vein resection stump. To the best of our knowledge, this is the first report of throm-bus removal by acute-phase endovascular reperfusion therapy to treat cerebral embolism likely caused by thrombus formation in the pulmonary vein stump after left upper lobectomy. When cerebral embolism of unknown cause develops after left upper lobectomy, thrombus formation in the pulmonary vein stump should be considered among the differential diagnoses. For acute-phase onset of cerebral embolism after pul-monary lobectomy, thrombus removal by endovascular reperfusion therapy may be considered as one of the therapies.