A blood clot in the body’s largest vein can lead to serious health complications, ranging from leg pain and swelling to a life threatening clot that lodges in the lungs.

The inferior vena cava (IVC) is the largest vein in your body, responsible for sending blood back to your heart from the lower part of your body. If a thrombus (blood clot) forms or settles in your IVC, the health risks can be severe.

While an IVC thrombus can be a life threatening disease, it can often be treated effectively with medications or various vascular procedures. Early diagnosis is critical.

Recognizing the symptoms of IVC thrombosis and responding quickly may save your life.

Learn more about thrombosis.

The large veins from your right and left legs join to form the IVC in your lower abdomen, where it then runs along your spine at the rear of your abdominal cavity. Your IVC then empties into the right atrium of your heart.

If a clot forms in your IVC or moves into the blood vessel from another deep vein, it’s called IVC thrombosis. This is a serious disease because a thrombus can travel to your lungs and form a life threatening pulmonary embolism.

IVC thrombosis can also block blood traveling up to your heart, causing potentially serious complications in your legs and elsewhere in your body.

IVC thrombosis is a rare disease, though it’s difficult to get a solid estimate of how often it occurs. People with deep vein thrombosis (DVT), a blood clot that forms in the deep veins of your legs and elsewhere in your body, face higher risks of IVC thrombosis. An estimated 4–15% of people with DVT go on to develop IVC thrombosis.

The location and size of the blood clot in your IVC usually determine the type and severity of your symptoms. They can vary considerably, but typically, IVC thrombosis symptoms may include leg pain, cramping, or both, as well as swelling and heaviness in one or both legs.

The pooling of blood in the veins of your leg may also lead to discoloration of your skin and sores (ulcers) that don’t completely heal.

You may also experience abdominal or back pain. Males may experience swelling in their scrotum.

If the clot travels to your lungs, you could experience chest pain and shortness of breath.

These symptoms are shared by many medical conditions, so it’s important to get a prompt and accurate diagnosis as soon as your symptoms emerge.

There isn’t a single test that can diagnose IVC thrombosis. Instead, a doctor or other healthcare professional may order one or more imaging tests if they suspect you have IVC thrombosis. Commonly used screenings include:

If IVC thrombosis is diagnosed, further imaging of the lungs may be ordered to check for the presence of a pulmonary embolism.

Treatment options for IVC thrombosis include:

Medication

Initial treatment for IVC thrombosis usually calls for heparin, an injectable drug used to prevent and treat blood clots. Moving forward, the primary treatment for IVC thrombosis is anticoagulant therapy. Anticoagulants (blood thinners) such as warfarin interfere with the clotting process and can help lower your risk of a subsequent clot formation.

Thrombectomy

Large clots may be removed or broken up with a procedure called a thrombectomy. During this procedure, a device is inserted through a catheter into your IVC. Using this device, the blood clot is suctioned out or withdrawn from your blood vessel.

Percutaneous transluminal angioplasty with stenting

If an individual has IVC thrombosis that lasts longer than 28 days, it’s considered chronic, and percutaneous transluminal angioplasty with stenting may be considered to help treat and manage the disease.

During percutaneous transluminal angioplasty with stenting, a very small balloon is inserted through a catheter to widen your IVC, and a small, metal mesh tube is inserted to keep the vein open.

The outlook for someone with IVC thrombosis depends largely on the cause of the blood clot. If you inherit a condition that predisposes you to blood clots but you consistently take your anticoagulant medications to reduce clotting complications, your outlook should be promising.

But some conditions, such as pancreatic cancer, can put abnormal pressure on your IVC and raise the risk of clots forming in your vein. Someone with a combination of an aggressive cancer and IVC thrombosis has a grim outlook.

A 2021 study in the Journal of Thrombosis and Haemostasis suggests that individuals with IVC thrombosis have a much higher mortality rate compared with people who have DVT. But the journal also suggests that the presence of cancer is only somewhat responsible for the disparity.

Is IVC thrombosis life threatening?

Yes, the mortality risk for someone with IVC thrombosis is double that of someone with lower-extremity DVT, according to a 2022 report in Vascular and Endovascular Review. The mortality rate for someone with DVT is about 6% within a month of diagnosis. But with early diagnosis and treatment, DVT can be successfully resolved.

What causes IVC thrombosis?

Blood clots can form in your IVC due to reasons such as pregnancy and hormone replacement therapy. Some people inherit genes that predispose them to venous clots. Cancer and traumatic injuries, including damage to your diaphragm or other internal organs, may also cause blood clots to form.

One other leading cause is the placement of an IVC filter in your vein to help prevent clots in your legs from moving up into your lungs. Blood can pool around the filter and cause a dangerous clot.

Can IVC thrombosis be prevented?

If you’re at risk of IVC thrombosis, a doctor may recommend anticoagulation therapy. Wearing compression stockings when sitting or standing for long periods can also reduce your risk of blood clots forming in your legs. Maintaining a moderate weight and exercising regularly may also help prevent IVC thrombosis.

IVC thrombosis can often be treated with a combination of blood thinners and procedures to remove or dissolve a large clot. The most important thing you can do to prevent serious complications is to get to a hospital if you notice sudden swelling in your legs or other serious symptoms that come on quickly.

Life threatening complications caused by blood clots should be considered medical emergencies. If you think you may be having IVC thrombosis, call 911 or local emergency services.

If you have new onset leg or abdominal cramps or both, it is recommended for you to get evaluated by a doctor as soon as you can. IVC thrombosis can usually be treated, but your best chance of a good outcome depends on responding quickly to symptoms and sticking with anticoagulant therapy once it’s prescribed.