Cardiopulmonary Syndromes (PDQ®): Supportive care - Patient Information [NCI] - Superior Vena Cava Syndrome
Superior vena cava syndrome (SVCS) is a group of symptoms that occur when the superior vena cava is partly blocked.
The superior vena cava is a major vein that leads to the heart. The heart is divided into four parts. The right and left atrium make up the top parts of the heart and the right and left ventricle make up the bottom parts of the heart. The right atrium of the heart receives blood from two major veins:
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The superior vena cava returns blood from the upper body to the heart.
The inferior vena cava returns blood from the lower body to the heart.
Different conditions can slow the flow of blood through the superior vena cava. These include a tumor in the chest, nearby lymph nodes that are swollen (from cancer), or a blood clot in the superior vena cava. The vein may become completely blocked. Sometimes, smaller veins in the area become larger and take over for the superior vena cava if it is blocked, but this takes time. Superior vena cava syndrome (SVCS) is the group of symptoms that occur when this vein is partly blocked.
SVCS is usually caused by cancer.
Superior vena cava syndrome (SVCS) is usually caused by cancer. In adults, SVCS is most common in the following types of cancer:
A blood clot that forms during the use of an intravenous catheter (flexible tube used to put fluids into or take blood out of a vein) in the superior vena cava. A clot may also be caused by pacemaker wires.
Infection or cancer in the chest that causes affected tissues to become thick and hard.
The symptoms of SVCS are more severe if the vein becomes blocked quickly. This is because the other veins in the area do not have time to widen and take over the blood flow that cannot pass through the superior vena cava.
The following tests may be done to diagnose SVCS and find the blockage:
Chest x-ray: An x-ray of the organs and bones inside the chest. An x-ray is a type of energy beam that can go through the body and onto film, making a picture of areas inside the body.
CT scan (CAT scan): A procedure that makes a series of detailed pictures of areas inside the body, taken from different angles. The pictures are made by a computer linked to an x-ray machine. A dye may be injected into a vein or swallowed to help the organs or tissues show up more clearly. This procedure is also called computed tomography, computerized tomography, or computerized axial tomography. A CT scan of the chest will be done to diagnose SVCS.
Venography: A procedure to x-ray veins. A contrast dye is injected into the veins to outline them on the x-rays.
MRI (magnetic resonance imaging): A procedure that uses a magnet, radio waves, and a computer to make a series of detailed pictures of areas inside the body. This procedure is also called nuclear magnetic resonance imaging (NMRI).
Ultrasound: A procedure in which high-energy sound waves (ultrasound) are bounced off internal tissues or organs and make echoes. The echoes form a picture of body tissues called a sonogram. The picture can be printed to be looked at later.