Overview of DVT & Pulmonary Embolism

Deep venous thrombosis (DVT), also called deep vein thrombosis, is a condition in which a blood clot (thrombus) develops in one or more of the deep veins, usually in the legs or arms. When this occurs, the blood clot, or a portion of the clot, can travel to the lung and block one of the branches of the pulmonary artery. This serious condition is called pulmonary embolism.

Blood clots also can form in veins that are near the skin's surface. This condition is called superficial venous thrombosis or phlebitis. Superficial blood clots do not cause pulmonary embolism. Inflammation of the vein in conjunction with a blood clot is called thrombophlebitis.

Deep vein thrombosis occurs most often in the deep veins of the legs (e.g., pelvis, thighs, knees, calves). The condition can occur as a result of damage to the vein lining, the disruption of normal blood flow (stasis), or with no known cause.

Patients who are inactive (e.g., following surgery) are at increased risk for developing deep vein thrombosis. Factors that increase the risk for pulmonary embolism include obesity, pregnancy, and surgery. Inherited (genetic) risk factors also may be associated with DVT and pulmonary embolism.

DVT/Pulmonary Embolism Incidence & Prevalence

Because DVT often resolves on its own without treatment, the exact incidence of the condition is unknown. Deep venous thrombosis is more common in patients over the age of 40. Incidence of pulmonary embolism doubles every 10 years after the age of 60.

In the United States, approximately 20–70 percent of patients who are hospitalized develop DVT. Deep vein thrombosis and pulmonary embolism are leading causes for preventable deaths in hospitalized patients. Pulmonary embolism causes about 200,000 deaths in the United States each year.

Publication Review By: Stanley J. Swierzewski, III, M.D.

Published: 05 Nov 2007

Last Modified: 30 Jul 2015