Venous thromboembolism (VTE) is a condition that occurs when a blood clot forms in a vein. VTE includes deep vein thrombosis (DVT) and pulmonary embolism (PE). DVT occurs when a blood clot forms in a deep vein, usually in the lower leg, thigh, or pelvis. DVTs can also occur in the arms, especially if there is a large intravenous central line in the vein. Pulmonary embolism occurs when a clot breaks loose and travels through the bloodstream to the lungs. VTE is common and as many as 600,000 VTE events occur each year in the United States.