What is superior vena cava syndrome?
SVCS is a partial blockage of the vein that carries blood from the head, neck, chest and arms to the heart. The major veins that return blood from the body to the heart are the superior vena cava and the inferior vena cava. The superior vena cava returns blood from the upper body to the heart, and the inferior vena cava returns blood from the lower part of the body. Valves connect these two major veins and control the flow of the blood into the heart. The superior vena cava is thin-walled, and the blood is under low pressure. It lies near lymph nodes in the chest. Therefore, when the lymph nodes are enlarged, as is the case in some cancers, the superior vena cava may be squeezed, slowing blood flow or even causing a complete blockage.
