Definition

Deep vein thrombosis (DVT) is a condition in which a blood clot forms in one of the deep veins of the body, most often in the legs.  DVT is a serious condition because the clot may break free of the leg veins and travel to the lungs impairing the body’s ability to deliver oxygen.   A blood clot in the lungs is referred to as a pulmonary embolism (PE).

Symptoms

About half of all DVT’s occur without symptoms.   Symptoms that do occur may include: swelling, pain, a “pulling” sensation, a change in the color of the skin, or warmth in the affected leg, ankle, or foot.      Symptoms of a PE include the sudden onset of shortness of breath or chest pain, dizziness, coughing up blood, or pain with breathing.

Causes

There are 3 typical causes of DVT’s: pooling of the blood in the veins, abnormalities of the blood clotting process, and injury to the veins.   Pooling of blood in the leg veins may occur whenever leg activity is restricted.  For example: prolonged airplane or car trips, after a surgery, or following any type of hospitalization or prolonged bed rest.
Abnormalities of the blood clotting process may occur due to illness, such as heart disease or cancer, or following a surgery or an injury.  In some cases blood clotting abnormalities, which contribute to the development of DVTs, may run in families.  Injuries such as fractures of the hip or leg bones, may damage the veins and increase the risk of DVT as well.

A diagnosis of cancer also carries an increased DVT risk.

Diagnosis

A venous ultrasound is usually helpful to diagnose most cases of DVT.
A lung scan or CAT scan of the chest helps in diagnosing a PE (pulmonary embolism).

Risk Factors for DVT

• Varicose Veins
• Prolonged sitting
• Inherited blood-clotting disorder
• Prolonged bedrest
• Injury or surgery
• Cancer
• Heart Failure
• Smoking
• Obesity
• History of prior DVT or PE
• Family history of DVT or PE
• Birth control pills or hormone replacement therapy

Treatment

There are three primary goals of DVT treatment:

• Stop the existing blood clot from growing
• Compress the tissues around the vein with stockings to improve the blood flow allowing the blood enzymes to dissolve the clots.
• Prevent a DVT from occurring again in the future

Anticoagulant medications are a first line of therapy.  Anticoagulants do not dissolve the existing blood clots; however they keep the existing clot from growing and prevent new blood clots from developing.  Warfarin and enoxaparin are examples of anticoagulant medications frequently used (please see handout regarding anticoagulants).

For maximum effectiveness these medications are generally prescribed for a minimum of 3-6 months and often for 1-2 years.

In some cases clot dissolving medications (thrombolysis) may be used or the clot may be mechanically removed (thrombectomy).  These treatments require hospitalization and are less common.  These are generally reserved for very large blood clots in the leg or blood clots that have traveled to the lungs.

Medical grade compression stockings are also recommended.  The stockings help to reduce the leg pain, swelling, and discoloration which may occur following a DVT and prevent long term effects of DVTs on the leg veins.   They may also prevent DVTs from occurring in the future.   They also help the one-way check valves from permanent damage.  Natural blood enzymes in the body help dissolve the clots and stockings support this process.