Optimal long-term pharmacological treatment of patients with venous thromboembolism that was unprovoked or associated with weak risk factors.

Unprovoked venous thromboembolism (VTE) tend to recur. Many factors, patient- or event-related, influence the individual risk of recurrence. After initial and long-term (usually for 3-6 months) anticoagulant therapy, extended anticoagulation has been recommended in patients at high risk of recurrence, provided they do not have a high risk of bleeding. Areas covered: The effect of different risk factors on the risk of recurrence is discussed, as well as risk factors for bleeding. The estimation of individual balance between these two risks is crucial to decide which can be the best treatment duration in single patients. The use of direct oral anticoagulants, with likely less risk of bleeding, may influence the balance. D-dimer assessment during and after anticoagulation is stopped is also commented for its role to help identifying the individual risk of recurrence. Expert commentary: All patients with a first VTE should be reconsidered after the initial 3-6 months of treatment. Anticoagulation can then be stopped or continued in relation to low or very high risk of recurrence, respectively. Serial D-dimer assessment during the first 2 or 3 months after anticoagulation is stopped is useful in patients with uncertain risk evaluation (especially after unprovoked events).