What is deep vein thrombosis?

Deep vein thrombosis (DVT) occurs when a blood clot, or thrombus, develops in the large veins in the lower extremities or pelvis. A clot that forms in these areas can be life threatening. The clot may break free and travel through the vein. A traveling clot is called an embolus and it can become lodged in the heart or the lung. This is called a pulmonary embolism and it can be fatal if not diagnosed and treated immediately.

DVT, which occurs in 2 million Americans every year, is caused by reduced blood flow through the deep vein, the tendency of a person's blood to clot too quickly and/or irritation or inflammation of the inner lining of the vein.

Symptoms of deep vein thrombosis

In about half the cases, there are no symptoms of deep vein thrombosis (DVT). When they are present, the most common symptoms are:

  • Swelling or change in color (to purple or blue) of one leg
  • Leg pain or tenderness in the calf muscle

These symptoms can develop suddenly or slowly over time. If you experience either of them, contact a doctor immediately.

Symptoms of a pulmonary embolism (PE) include:

  • Chest pain
  • Shortness of breath
  • Rapid pulse
  • Cough
  • Feeling of apprehension
  • Sweating
  • Fainting

Symptoms of PE are similar to those for other medical conditions, such as heart attack. Whatever the underlying cause, these symptoms need to be medically evaluated immediately.

Risk factors of deep vein thrombosis

Deep vein thrombosis (DVT) affects men and women of all ethnic and socioeconomic groups equally. Factors that can contribute to this condition are:

  • Smoking
  • Later stages of pregnancy  
  • Leg injury
  • Recent surgery
  • Inactivity
  • Age

Diagnosis of deep vein thrombosis

A suspected deep vein thrombosis (DVT) is confirmed using:

  • Duplex ultrasound: Duplex ultrasound is a type of ultrasound for assessing blood flow and structure of the leg veins.
  • Magnetic resonance venography (MRV): A diagnostic procedure that produces detailed, three-dimensional images, magnetic resonance technology involves the use of magnets, radiofrequencies and computers to produce the images. MRV also includes the use of a contrast dye to help visualize the veins.

Treatment for deep vein thrombosis

Anyone with confirmed deep vein thrombosis (DVT) is treated immediately to prevent pulmonary embolism.  Anticoagulant medications are given to reduce clotting or thrombolytics are given to dissolve the clot.

Thrombolytics are usually used in only the most severe cases or those in which the clot occurs higher up in the thigh or in the pelvis. The drug is delivered directly to the clot through a catheter inserted in a vein. Sometimes the softened clot is removed by a tiny vacuum cleaner-like device. Once the clot is gone, balloon angioplasty and stent placement may be performed. These are analogous to those performed on arteries (see chronic limb ischemia ). If a person has a severe clot, but is not a good candidate for thrombolytics, the clot may be removed through an incision in the groin.

Long-term treatment may include the three E’s: exercise, elevation and elastic compression.

  • Exercise: Exercise helps pump blood through the legs and builds muscle that can promote better circulation.
  • Elevation: Elevating the legs can help to instantly relieve pain. A doctor may also instruct a patient to elevate the legs above the heart three or four time a day for about 15 minutes at a time. This can help to reduce swelling. If prolonged standing or sitting is necessary, bending the legs several times will help promote blood circulation.
  • Elastic compression: Elastic compression stockings increase in tightness from the toes to the calves. They squeeze the leg veins, exerting additional pressure that helps to prevent blood from flowing backwards.