[Deep-vein thrombosis and pulmonary embolism due to air travel]

In recent years, the association between air travel and the incidence of deep-vein thrombosis or pulmonary embolism has become clearer. Epidemiologic studies reveal an increased relative risk of thromboembolism after flights of more than 8 hours and especially in subjects at higher risk for this disease, due, for example, to congenital thrombophilia or the use of oral contraceptives. However, the absolute risk of deep-vein thrombosis or pulmonary embolism after prolonged air travel is very small. Studies have shown that a combination of factors present during prolonged air travel may account for increased activation of coagulation. There is no definitive proof that elastic stockings are effective in reducing the incidence of clinically relevant thromboembolism during air travel. Acetylsalicylic acid is not effective in the prevention of thrombosis during air travel and may be dangerous. Prophylactic subcutaneous low molecular weight heparin may be effective to prevent air travel-associated thrombosis. However, pending more solid evidence, this strategy should only be used cautiously, e.g. only in patients with a high risk of thrombosis who are planning a long flight.