obstruction of a blood vessel by a blood clot that has become dislodged from another site in the circulation. The clot can block blood flow and cause: Leg pain or tenderness of the thigh or calf. Leg swelling (edema) Skin that feels warm to the touch. Unexplained shortness of breath, Rapid breathing, Fast heart rate and Light headedness or passing out. The most common triggers for venous thromboembolism are surgery, cancer, immobilization and hospitalization. Deep vein thrombosis forms in the legs when something slows or changes the flow of blood. Thromboembolism: Formation in a blood vessel of a clot (thrombus) that breaks loose and is carried by the blood stream to plug another vessel. The clot may plug a vessel in the lungs (pulmonary embolism), brain (stroke), gastrointestinal tract, kidneys, or leg. Anticoagulant and thrombolytic therapy options are available for the treatment of venous thromboembolism (VTE). Anticoagulant therapy prevents further clot deposition and allows the patient's natural fibrinolytic mechanisms to lyse the existing clot.