What is deep vein thrombosis (DVT)?

When blood moves too slowly or not at all, it can collect (pool) in the veins forming a clot. Deep vein thrombosis (DVT) is a blood clot or thrombus in a deep vein. These blood clots are most common in the leg, but they may occur in the arm or other part of the body. Part of a clot, called an embolus, can break off and travel to the lungs. This is a pulmonary embolus (PE) and can cut off blood flow to all or part of the lung. PE is an emergency and may cause death.

Healthcare providers use the term venous thromboembolism (VTE) to describe these 2 conditions, DVT and PE. They use the term VTE because the two conditions along with their prevention and treatment are closely related.

Who is at risk for deep vein thrombosis?

Anyone can develop a blood clot, but certain factors may raise your risk for one. Anything that slows blood flow, injures the lining of a vein or increases blood clotting can make you more likely to have DVT. You are at risk for DVT if you:

  • Are overweight or obese

  • Have a blood-clotting disorder

  • Are older than age 60

  • Had surgery

  • Have spent a long period of time not moving, such as staying in the hospital or traveling on a long trip

  • Take birth control pills or hormone replacement therapy

  • Are paralyzed

  • Are pregnant

  • Smoke

  • Have a central venous catheter (for example, in a large vein in the chest)

You are also at higher risk if you have certain diseases and conditions, such as:

  • Previous blood clot

  • Varicose veins

  • Heart problems, such as heart failure or heart attack

  • Inflammatory bowel disease

  • Lupus, an autoimmune system disease

  • Cancer and some cancer treatments

What are the symptoms of deep vein thrombosis?

DVT may happen without symptoms. When symptoms do happen, they may be sudden. They may appear around the site of the DVT, such as the calf or thigh. You may have these common symptoms:

  • Pain, especially deep in the muscle

  • Swelling (edema)

  • Soreness or aching

  • Redness and warmth in the leg, arm or other area

  • Low-grade fever

These symptoms may mean that you have a blood clot. The symptoms of a blood clot may also look like other health problems. Always see your healthcare provider for a diagnosis.

How is deep vein thrombosis diagnosed?

Your healthcare provider will ask about your health history and do a physical exam. You may also need these other tests:

  • Duplex ultrasound. This procedure involves placing ultrasound gel on the affected area and then moving a handheld device across it. A picture of the blood flow is displayed on a screen. Duplex ultrasound is the most common test for DVT.

  • Blood tests. Blood tests may be done to look for blood clotting and other problems.

How is deep vein thrombosis treated? 

Treatment will depend on your symptoms, age and general health. It will also depend on how severe the condition is.

The goals of treatment are:

  • To prevent the clot from getting larger

  • To stop the clot from traveling to your lungs

  • To lower the chance of another blood clot forming

Treatment may include:

  • Blood thinners (anticoagulant medicines). These medicines lower the ability of the blood to clot. They are a main treatment for DVT. These medicines may be given as a shot, through an IV (intravenous) line into a vein or in pill form. The most common side effect of blood-thinning medicine is bleeding.

  • Clot busters (fibrinolytics or thrombolytics). These medicines are used to break up clots.

  • Inferior vena cava filter. In some cases, a filter is placed in the vena cava. This is the large vein that returns blood from the body to the heart. This filter prevents clots from reaching the heart and lungs.

What are possible complications of deep vein thrombosis?

The possible complications of DVT are:

  • Pulmonary embolus. This can cut off blood flow to all or part of the lung. PE may develop quickly. It is a medical emergency and may cause death.

  • Chronic venous insufficiency. This may happen after a blood clot in a leg vein. It means that a vein no longer works well. It is a long-term condition where blood pools in the vein instead of flowing back to the heart. Pain and swelling in the leg are common symptoms.

  • Post-thrombotic syndrome. This health problem may also happen after a blood clot in a leg vein. It may occur in the weeks or months following a DVT. It is a long-term problem. It causes pain, swelling and redness. Ulcers and sores can also happen. All these symptoms may make it hard to walk and take part in daily activities.

How can I help prevent deep vein thrombosis?

You can help prevent DVT with these steps:

  • Take blood thinners, if your healthcare provider has prescribed them for you.

  • Wiggle your toes and move your ankles if you sit or lie down for long periods of time.

  • Walk. Get up and move as soon as possible after surgery or illness.

  • Wear elastic or compression stockings, if your healthcare provider has prescribed them.

If you are in the hospital, your risk for blood clots increases. Your healthcare provider may prescribe the use a sequential compression device (SCD) or intermittent pneumatic compression (IPC). Special sleeves go around both legs. They are attached to a device that applies gentle pressure to the legs. Remove the sleeves so that you do not trip or fall when you are walking, such as when you use the bathroom or shower. Ask for help if you can’t remove and replace the sleeves. 

When you travel and must sit for long periods of time, you can lower your risk of a blood clot by: 

  • Walking up and down the aisles (if traveling by plane or bus)

  • Stopping about every hour and walking a little (if traveling by car)

  • Moving your legs, ankles and toes while sitting

  • Wearing loose clothing

  • Limiting the amount of alcohol you drink

  • Drinking a lot of water and other healthy drinks

  • Talking with your healthcare provider about a program of regular exercise

  • Staying at a healthy weight

  • Quitting smoking, if you smoke