D-dimer to Predict Recurrence in Patients With Multiple Episodes of Venous Thromboembolism

Inclusion Criteria: * Patients with at least two episodes of objectively documented venous thromboembolism (at least one proximal deep vein thrombosis or pulmonary embolism) * Ongoing treatment with oral anticoagulants for at least a) 12 months in case idiopathic DVT was the last event; b) 6 months in all other cases * Age \> 18 years * Informed consent provided Exclusion Criteria: * Pregnancy/puerperium * One or more episodes of massive pulmonary embolism * Last event isolated idiopathic pulmonary embolism * Two or more idiopathic VTE events * First degree relatives with recurrent VTE * Right ventricular disfunction or pulmonary hypertension * Active cancer * Antiphospholipid antibodies syndrome * Antithrombin deficiency * Homozygous Factor V Leiden or G20210A prothrombin mutation * Heterozygous Factor V Leiden and G20210A prothrombin mutation * Concomitant congenital thrombophilic mutations * Concomitant indications to long term oral anticoagulant treatment * Severe cardiorespiratory insufficiency * Severe liver or renal disease (creatinine clearance \> 2 mg/dL) * Limited life expectancy * Geographic inaccessibility