Superior vena cava thrombosis and paradoxical embolic stroke due to collateral drainage from the brachiocephalic vein to the left atrium

Abstract

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.

Keywords: Brachiocephalic veins; catheterization, central venous/adverse effects; vena cava, superior; venous thromboembolism/diagnosis/etiology/prevention & control/therapy.

Fig. 1 Transesophageal echocardiogram of the left and right atria shows contrast medium in the left atrium, suggesting a right-to-left shunt.

Fig. 2 Phlebograms in A) posteroanterior and B) lateral projections show severe superior vena cava stenosis and large, newly formed collateral veins (arrowheads), which originate from the brachiocephalic venous trunk and empty into the left atrium. B) Arrow points to the expected site of origin of the azygos vein, which is not visible due to occlusion.

Fig. 3 Phlebogram (posteroanterior projection) shows stent deployment in the superior vena cava, proximal to the right atrium.

Fig. 4 Postprocedural phlebogram shows the disappearance of the collateral veins between the brachiocephalic vein and the left atrium. The arrow points to the expected site of origin of the azygos vein, which is still not visible due to occlusion.