Clotting in the air.

摘要

In recent years there has been much debate about an association between long-distance air travel and thrombosis.12 In today's Lancet, Anja Schreijer and colleagues3 report a study done in the framework of the WHO Research Into Global Hazards of Travel Initiative (WRIGHT) which adds an important piece of evidence to the mosaic of travel-induced thrombosis. The Dutch group compared the concentrations of markers of coagulation activation in blood samples of healthy volunteers drawn before, during, and immediately after an 8-h flight, with those taken at the same time points during 8 h of immobilisation in a cinema, and during normal daily activities. In doing so, the conditions of immobilisation and hypobaric hypoxia (flight) could be disentangled from immobilisation alone (cinema) and be controlled for circadian rhythm (daily activities). By including almost 40% of participants with the factor V Leiden mutation or women on oral contraceptives, itwas possible to assess the effect of these risk factors on coagulation activation. The authors found increased concentrations in markers during flight compared with the other two situations, especially in volunteers with genetic (factor V Leiden) or extrinsic (oral contraceptives) risk factors. They conclude that activation of coagulation and fibrinolysis occur in some susceptible individuals after an 8-h flight due to a mechanism inherent in air travel, in addition to immobilisation.