Venous thromboembolism, defined as deep vein thrombosis or pulmonary embolism, is a major health concern in the United States, with more than 900,000 thrombotic events reported each year, resulting in at least 600,000 hospitalizations and approximately100,000 deaths.1-3 Total treatment costs during the initial year after an index venous thromboembolism have been estimated to surpass $20,000 per patient.4