Is There Something About Air Travel Besides Immobilization that Increases Risk of DVT?
By Louis Kuritzky, MD, Clinical Assistant Professor, University of Florida, Gainesville. Dr. Kuritzky is a consultant for GlaxoSmithKline and is on the speaker's bureau of GlaxoSmithKline, 3M, Wyeth-Ayerst, Pfizer, Novartis, Bristol-Myers Squibb, AstraZeneca, Jones Pharma, and Boehringer Ingelheim.
This article originally appeared in the May 2006 issue of Internal Medicine Alert. It was reviewed by the physician editor, Stephen Brunton, MD, and peer reviewed by Gerald Roberts, MD.
That deep venous thrombosis (DVT) can occur after air flight is not a new observation, having been first reported in the 1950s. Recent data have singled out very long flights (8 hours or greater) as being remarkably more important for DVT risk than shorter flights.1 Generally, risk for DVT with air flight has been simply attributed to only one of the 3 characteristics of Virchow's Triad: stasis (due to immobility). Schreijer and colleagues studied the impact of clotting factor activation associated with air flight.
To differentiate simple immobilization on the ground, from immobilization with air flight, study subjects were divided into 3 groups: a real 8-hour plane flight, an 8-hour period of immobilization while watching successive movies, or the control of 8 hours of normal daily activities. The 71 men and women participated in 2 cross-over periods, so that all subjects experienced all 3 group activities.
Several coagulation factors were monitored. After flight, thrombin-antithrombin complex was elevated (indicating increased thrombotic activation), but not after 8 hours of movie immobilization or daily activities. Coagulation activation was most marked in women on oral contraceptives who had known factor V Leiden at baseline. Schreijer and colleagues postulate that the hypobaric hypoxia encountered in flight explains the coagulation activation. Advice to avoid protracted immobility on long flights can be helpful, but may not be fully protective, since other mechanisms in addition to immobility appear to be etiologic.
Reference
1. Schreijer AJ, et al. Activation of Coagulation System During Air Travel: A Crossover Study. Lancet. 2006;67:832-838.
That deep venous thrombosis (DVT) can occur after air flight is not a new observation, having been first reported in the 1950s.You have reached your article limit for the month. Subscribe now to access this article plus other member-only content.
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