Fatal pulmonary embolism has been reported to occur in up to 200,000 patients each year in the United States.1,2 Although many of these deaths occur in patients with terminal disease, many of these deaths also occur in patients who would otherwise have survived to live a normal life. The rate of fatal pulmonary embolism has been estimated to be approximately 3% after total hip replacement,1,2 between 0.1% and 0.8% in patients undergoing elective general surgical operations,1,2 and between 4% and 7% in patients with hip fractures.1,2 Fatal pulmonary embolism is also an important complication in patients who are convalescing from congestive cardiac failure or respiratory conditions.
Two approaches can be used to prevent clinically significant venous thromboembolism. These are primary prophylaxis and early detection and treatment of subclinical venous thrombosis. Primary prophylaxis is more effective and less expensive and is the method of choice in most