Flying and thromboembolism

Abstract

The risk of deep vein thrombosis and pulmonary embolism increases during, and for several weeks after, flights of four or more hours. Venous stasis due to prolonged immobility and obstruction to venous return from the legs is believed to accentuate any inherent predisposition of the traveller to venous thromboembolism. The incidence increases with flight duration, oestrogen ingestion, a prior episode of venous thromboembolism and coexisting medical or surgical conditions associated with increased risk. Clinically evident episodes occur at an incidence of about one per 4500 long-haul flights. The incidence increases in patients with other risk factors for thromboembolism, so prophylaxis with low molecular weight heparin can be considered. In people at low risk the adverse effects of prophylaxis outweigh the potential benefits.