What Is Deep Vein Thrombosis?

Deep vein thrombosis (DVT) occurs when a clot forms in a deep-lying vein, usually in the legs. Such a clot is dangerous because the clot my break loose, travel through the bloodstream, and block arteries in the lungs (called a pulmonary embolus), causing permanent damage or death.

How Does DVT Occur?

DVT may occur when the blood moves through deep veins in your legs more slowly than normal or when there is some factor that makes your blood more likely to clot. When you are bedridden (after surgery, for example) or when you sit still for a long time (such as during a long plane flight or car ride), your blood moves more slowly. Blood pools in the larger veins of your legs, and clots may form. Also, injury, major illness, and some medicines increase the tendency for blood to clot.

Your risk for having DVT increases if you have these conditions:

  • Prolonged sitting
  • Immobility or bed rest
  • Orthopedic surgery
  • Fractures of the hip or leg
  • Pelvic surgery
  • Stroke
  • Congestive heart failure
  • Varicose veins
  • Obesity
  • Some cancers
  • Cigarette smoking

What Are the Symptoms of DVT?

About half of people with DVT have no symptoms until a clot blocks a major vein. When DVT causes symptoms and blocks blood flow, symptoms may include swelling, redness, warmth, tenderness or pain, and discolorization to the affected limb.

How Is DVT Diagnosed?

Your doctor will ask about your medical history and your symptoms. Your doctor will examine you, especially any abnormal areas, such as a swollen leg. Sometimes the clotted area can be felt deep in the calf or thigh. Your doctor may measure your calves or thighs to compare the sizes on the left and right sides.

Testing to confirm a DVT include:

  • IPG (impedance plethysmography) measures vein function in the arm or leg. A technician will place a pressure cuff on your arm or leg and measure how fast the veins empty.
  • Duplex ultrasound – an ultrasound picture that measures the blood flow through the veins.
  • Contrast venography (used when other tests don’t give a definite diagnosis). A dye is injected into a vein while x-ray pictures are taken. It usually shows any blockages in your veins.

How Is DVT Treated?

DVT’s are treated with anticoagulants (commonly called “blood thinners”) and bed rest. The goals of treatment are to prevent more blood clots, prevent complications such as pulmonary embolism and stroke, and to allow time for the clot to dissolve.

Typically treatment is started in the hospital and continues once you go home. You may need to take anticoagulants for 6 months or in some situations indefinitely.

How Can DVT Be Prevented?

If you have had a DVT or have risk factors for developing DVT, you can help prevent DVT by following these guidelines:

  • Avoid sitting for long periods of time
  • Keep your legs elevated when you are in bed or sitting down. Leg elevation promotes the return of blood through the leg veins.
  • Avoid crossing your legs and ankles when you sit
  • Get regular exercise according to your doctor’s advice
  • Maintain a healthy body weight
  • Stop smoking.