Abnormal superior vena cava morphology Obstruction of the superior vena cava 2017-05-27T12:23:27Z Superior vena cava syndrome Diagnosis of superior vena cava obstruction may be made by computed tomography with contrast and other means. Blockage of blood flow through the superior vena cava (SVC). Because the venous drainage from the upper extremities, upper thorax and head is obstructed, SVC obstruction presents with symptoms related to engorgement of these areas. Both the degree of SVC compromise and the extent of collateral veins determine the varied clinical presentation, which can be as mild as slight facial and upper extremity edema or as dire as intracranial swelling, seizures, hemodynamic instability and tracheal obstruction. Superior vena cava obstruction