The Bottom Line:
- Longer duration of anticoagulation decreases risk for recurrent VTE
- If DVT or PE related to transient risk factor, anticoagulation for 3 months recommended and appears as effective as anticoagulation for 6 months
Reference: The Task Force for the Diagnosis and Management of Acute Pulmonary Embolism of the European Society of Cardiology (ESC). Guidelines on the diagnosis and management of acute pulmonary embolism. European Heart Journal (2008) 29, 2276–2315.
Summary: The need for long-term anticoagulant treatment of VTE is supported by three lines of evidence, all from randomized trials. One of these studies showed a 20% rate of symptomatic extension and/or recurrence within 3 months in patients with symptomatic calf-vein thrombosis not receiving long-term anticoagulant treatment. Another study proved the lack of efﬁcacy of low-dose unfractionated heparin as an alternative to VKAs after proximal DVT. In further studies, reducing the duration of treatment to 4 or 6 weeks resulted in an increased recurrence rate compared with the conventional duration of 3-6 months.