Deep Vein Thrombosis

Deep Vein Thrombosis (DVT) is a condition where a blood cot forms in one of the deep veins within the pelvis, thigh, or calf. Deep vein thrombosis can also occur in the upper extremities, although it is less common. Deep vein thrombosis is a serious condition because the clot may move to the lungs. This condition is called "pulmonary embolism" and requires immediate treatment. A large clot blocking circulation of blood to the lungs can result in death.

Causes of DVT:

Deep vein thrombosis can occur as a result of prolonged periods of immobility. Long flights on an airplane, prolonged bedrest following surgery or during a lengthy hospitalization are examples of predisposing factors for the development of deep vein thrombosis. Other causes of deep vein thrombosis are an abnormality of the blood itself which causes it to clot more readily than normal. Inherited or acquired conditions such as protein C deficiency, protein S deficiency, antithrombin III deficiency, factor V Leiden mutation, lupus anticoagulant or anticardiolipin antibodies can predispose a person to develop lower extremity deep vein thrombosis.

Diagnosis:

The diagnosis of deep vein thrombosis is suspected when a patient develops sudden onset of pain and swelling in the lower extremity, particularly in the setting of one of the predisposing factors mentioned above. The diagnosis cannot be made solely on clinical examination, but rather requires performance of an ultrasound test of the veins of lower extremities.

Treatment:

If a diagnosis of deep vein thrombosis is confirmed, patients are usually treated with anticoagulants. Typically, intravenous heparin or injectable enoxaparin (Lovenox) is begun as soon as the diagnosis is made because these anticoagulant medications are fast acting and serve to help prevent progression of clotting in the extremity. A typical treatment course would be to begin heparin or enoxaparin ( Lovenox) and then, over the course of about 5 days, convert the patient from injectable therapy to oral anticoagulant therapy (such as warfarin) and continue the warfarin (Coumadin) for periods typically not less than three months in duration. In the early stages of DVT, it is common to confine a patient to bedrest to prevent movement of the clot from the lower extremities into the lungs (pulmonary embolus). After a period of approximately five days, patients typically are allowed to begin ambulation. Another form of therapy for acute DVT is thrombolysis. With this therapy, clot-dissolving medications are injected into the portion of the vein where the clot has developed. Although thrombolysis dissolves the clot rapidly, it carries a risk of serious bleeding. Among the most worrisome sites of bleeding is the brain which can lead to a stroke. It is extremely unlikely and uncommon that a surgeon would recommend surgical removal of a clot in the lower extremities. Treatment is almost always medical in nature using heparin and Coumadin.

Vena Caval Filter:

The vena caval filter is a "trap" that is placed into the vena cava, the main vein in the body which is located in the abdominal cavity. The filter is positioned in the vena cava by passing it (under x-ray guidance) from a vein in the neck or leg. The filter is designed to trap clots that may move from a vein in the leg or pelvis before they can reach the lungs and cause major morbidity or death. Vena caval filters are effective in preventing death. They are used if in the judgment of the vascular surgeon the patient is at high risk for a pulmonary embolus or if there is some reason that blood thinners cannot be used to treat the lower extremity DVT.

Postphlebitic Syndrome:

Postphlebitic syndrome is a condition of swelling and pain in a lower extremity that has been affected by DVT. The postphlebitic syndrome can last for a very long time (more than a year) and can be very disabling. The cause of postphlebitic syndrome is persistent obstruction of blood flow through the damaged veins. If the clot in a vein affected by DVT does not dissolve within the first few weeks after initiation of anticoagulant therapy, it frequently becomes scarred to the inside of the vein wall and serves as a permanent site of obstruction. Over time, the leg will often gradually improve as alternate veins enlarge and create avenues of blood flow out of the leg. This takes time, however, and during the period of time that the blood flow out of the leg is impeded by the DVT, the leg will swell and become painful and sometimes take on a darker color due to the accumulation of blood in the extremity. This constellation of symptoms and signs is called "postphlebitic syndrome". Unfortunately, the treatment is essentially the passage of time and waiting for the body to develop new vein pathways for blood to exit the leg. Patients are often advised to wear elastic support stockings to minimize the swelling of the extremities since swelling is associated with discomfort. Over the years, various vascular surgery operations have been attempted to relieve the vein obstruction, but they are of minimal benefit and are rarely recommended for this condition.