Deep vein thrombosis in airline passengers - The incidence of deep vein thrombosis and the efficacy of elastic compression stockings

A prospective study to determine the incidence of deep vein thrombosis in p assengers on long haul flights, and to determine the efficacy of elastic co mpression stockings in reducing this incidence, Two hundred patients over t he age of SO, with no past history of venous thromboembolic disease, no co- existing medical problems, and no specific risk factors, undergoing flights of eight hours or more, have been accessed. All patients have undergone Du plex ultrasound imaging two weeks prior to departure. Immediately prior to departure, a repeat Duplex ultrasound scan was carried out. and blood taken for D-dimer and thrombin antithrombin complex (TAT) as markers of a hyperc oagulable state and soluble vascular cell adhesions molecule (VCAM-1). All patients completed a pre-travel questionnaire. The patients were randomly a llocated to receive or not receive elastic compression stockings. On return , each patient was again scanned, and a further blood sample taken for anal ysis. Those patients with high levels of D-dimer, TAT or VCAM-1, underwent a full thrombophilia screen, Those patients with a positive Duplex scan on visit one or two were excluded from the study. Those patients with a positive sca n on return were considered to have developed thromboembolic disease, and u nderwent further investigations. The results are being analysed on an intention to treat basis. The study wi ll conclude when 100 patients have been recruited to each group.