The aetiology of acute pulmonary embolism and the identification of high risk groups.

Although the cause of venous thrombosis remains obscure, preventive methods have been described. The fact that pulmonary embolism continues to cause a high death toll suggests that there is still a failure to recognize the need for prevention or to employ those prophylactic methods that are known to be effective. While it may be impracticable to offer prophylactic treatment to all patients at risk, an awareness of the important predisposing factors and the application of effective prophylaxis to high risk cases could bring about a reduction in the mortality rate from a disease that at present causes as many unnecessary deaths as motor vehicle accidents.