Deep Vein Thrombosis (DVT)

DVT stands for deep venous thrombosis, one of the most common circulatory problems in adults. Blood clots often form in the deep veins—usually of the leg or pelvis—during periods of immobility or after injury or surgery. Although some clots resolve on their own, pieces of a clot may break off and travel to the lungs. A blood clot that lodges in the narrow arteries of the lungs is called a pulmonary embolism, or PE, and it may be life-threatening if it blocks circulation to a large enough portion of the lungs.

An estimated 2 million Americans develop DVT each year, and up to 200,000 of them may die from pulmonary embolism. DVT often damages the affected vein, and patients may develop long-term leg pain and swelling due to chronic venous insufficiency. Those who survive a PE may suffer from heart damage and shortness of breath due to high blood pressure in the lungs, called pulmonary hypertension.

Situations that increase the risk of DVT and PE include:

• Increased age (usually over 40 years)
  
• Prolonged immobility due to:
  
  • Medical illness (e.g. pneumonia, congestive heart failure, infectious disease, etc.)
  • Surgery
  • Trauma
  • Leg fractures
  • Lengthy travel in an airplane, train, car, or bus
  • Cancer
  • Inherited blood clotting tendency
  • Obesity
  • Varicose veins
  • Pregnancy
  • Oral contraceptives (birth control pills)
  • Hormone replacement therapy (HRT)

Patients who develop DVT may have no symptoms at all, but the most common symptoms are pain, swelling, and discoloration in just one leg. Sometimes, blood clots form in the leg veins that are close to the skin, causing a painful red streak and sometimes a tender lump. But when clots form in the deep veins—which are surrounded by muscle—patients may have no visual evidence. In addition, the risk of developing a PE is greater when the deep veins are involved.

When physicians suspect that a patient may have DVT, they may order an ultrasound examination. This is a quick, painless, and non-invasive diagnostic method that is very reliable if performed by an experienced vascular technologist. When the physician suspects a PE, a perfusion lung scan, CT scan of the chest, or angiogram of the lung's arteries may be used to help make a diagnosis.

Treatment of DVT usually requires "blood-thinning" medications called anticoagulants that prevent the blood clot from growing, and reduce the risk of pulmonary embolism. Some anticoagulants are administered by intravenous (IV) infusion or by injection, while others are administered orally in tablet form. Although patients with DVT are typically hospitalized for several days for treatment, newer anticoagulants known as low molecular weight heparins (LMWH) have allowed certain patients with uncomplicated DVT to shorten their hospital stay and administer the drug by injection at home. When blood clots are large enough to threaten life or limb, physicians sometimes recommend special treatment to dissolve the clot.

When a PE has been confirmed, rapid intervention is critical because another PE could be fatal. Clot-dissolving drugs similar to those used for patients suffering a heart attack (myocardial infarction) or large leg vein clots can also be used to treat people who have a PE blocking a large vessel in the lungs. After the patient leaves the hospital, treatment may be continued using an oral anticoagulant drug for months to years, depending on the situation. This requires regular blood monitoring because many factors, including other drugs and certain foods, can affect the dose necessary to achieve the desired effect. The greatest risks during treatment for DVT and PE are recurrent blood clots (if not enough anticoagulant is used) and bleeding (when the effect is too great).

If you or someone you love may be at risk of blood clots, consult your physician.