What Is Deep Vein Thrombosis (DVT)?

A deep vein thrombosis, or DVT, is a blood clot that occurs in a vein. A vein is a type of blood vessel that carries oxygen-poor blood back to the heart (versus arteries, which are blood vessels that carry oxygen-rich blood throughout your body).

DVT blood clots usually occur in the leg, though they can occur in the arm or other veins. The clot can block blood flow and lead to painful swelling in the affected limb. A DVT may also lead to a pulmonary embolism (PE), which happens when a DVT blood clot breaks off and travels through the bloodstream to the lungs.

How does a DVT blood clot form?

Watch this short video to see how a DVT forms and the symptoms it can cause.

More people die of DVT/PE each year than
breast cancer, traffic accidents, and HIV combined.

DVT/PE 100,000
Breast Cancer, Traffic Accidents, and HIV 82,840

DVT and PE blood clots may also be referred to as venous thromboembolism (VTE). It is estimated that between 300,000 and 600,000 Americans per year are affected by DVT or PE. These conditions are the third-most-common diagnoses related to blood vessels after heart attack and stroke.

What causes a DVT?

DVTs are often caused by a change or slowing of blood flow. For example, your blood flow can slow down enough to form a clot when sitting on long flights, after surgery, or if you have to spend a long time in bed because you are sick or hospitalized. DVT blood clots are also more common in women who are pregnant or taking birth control or other hormonal drugs, overweight people, or people with cancer or autoimmune disorders. People with a family history of DVT are also at risk. Learn more about DVT risk factors.

When the doctor came in, he explained to me what was going on. He said, you dodged a bullet here.

Hear what Bob’s doctor told him about his DVT.

What are the complications of DVT?

A DVT doesn’t just affect the limb where it occurs. There are complications of DVT that can have other serious effects on your health because it involves your cardiovascular system. Cardiovascular means "having to do with the heart and blood vessels."

Your cardiovascular system is also known as the circulatory system. Your heart, arteries, veins, and lungs all work together to move nutrients and oxygen-rich blood to every single part of your body. Because this network connects everything from your brain to your toes, a problem—like a DVT blood clot—in one part of your body can cause problems somewhere else.

For example, when you have a DVT, it blocks the blood flowing through your vein, often causing painful symptoms. But the biggest risk is that the blood clot could break off and travel through the bloodstream to your lungs, causing a pulmonary embolism (PE), which can be life threatening. This is why it's so important to pay attention to potential symptoms of a DVT and seek treatment right away.

In addition to following the treatment plan laid out by your healthcare professional, having a heart-healthy lifestyle can help lower your risk for other cardiovascular diseases. Learn more about living well after a DVT.

Infographic showing the cardiovascular system and how blood flows from the heart to body to lungs