Superior Vena Cava Thrombosis and Paradoxical Embolic Stroke due to Collateral Drainage from the Brachiocephalic Vein to the Left Atrium

摘要

Thrombosis involving a permanent infusion catheter in the subclavian vein and superior vena cava is relatively common, especially in cancer patients. Edema of the arms and head is a well-known clinical consequence of this thrombosis, with an intrinsic risk of pulmonary embolism; however, systemic embolization into the cerebral circulation has not been reported as a sequela. Herein, we describe the case of a 56-year-old man with metastatic prostate cancer who developed superior vena cava syndrome due to extensive thrombosis in the presence of a central venous catheter that was used for long-term chemotherapy. The patient's case was complicated by a cerebrovascular accident that was most likely caused by a paradoxical air embolism. A clear mechanism for the embolism was provided by a network of collateral veins, which developed between the brachiocephalic vein and the left atrium due to the superior vena cava obstruction and resulted in a right-to-left shunt. We discuss diagnosis and treatment of the condition in our patient and in general terms. Key words: Brachiocephalic veins, catheterization, central venous/adverse effects, vena cava, superior, venous thromboembolism/diagnosis/etiology/prevention & control/therapy Permanent indwelling central venous catheters (CVCs) are used in many types of therapeutic interventions. These catheters can be a source of infection and thrombosis. The incidence of CVC-related thrombosis is as high as 30% in adults 1 ; unfortunately, current guidelines are inadequate for preventing this sequela. 2,3 Herein, we report the case of a patient with CVC-induced superior vena cava (SVC) syndrome caused by thrombosis. The condition was complicated by apparent paradoxical systemic air embolization. A likely mechanism for embolization was a network of functional collateral veins that had developed between the brachiocephalic vein and the left atrium.