Venous Thromboembolism from Air Travel The LONFLIT Study.

Evaluates the incidence of deep venous thrombosis (DVT) occurring as a consequence of long flights. Absence of cardiovascular disease and drug use in low-risk subjects; Use of ultrasound scans to diagnose DVT after the flights; Absence of DVT on low-risk groups; Comparison of the incidence of DVT between subjects wearing stockings and those that do not.