A study that was recently published in the British Medical Journal suggests that patients with deep vein thrombosis (DVT) or pulmonary embolism (PE) with no known risk factors for recurrence may be safely treated with anticoagulation for 3 months. The study included 749 patients with DVT, PE, or both. They were divided into groups and were treated for either 3 months or 6 months with an international normalized ratio target range of 2.0 to 3.5. There were no significant differences in adverse outcomes (death, failure to resolve, extension of clot, or recurrence during or after treatment). The group treated for 6 months had 8 episodes of major hemorrhage, all of which occurred in the first 4 months of treatment. No major hemorrhages were reported for the 3-month group.
The authors of the study conclude that there may be little advantage to an extended course. Other experts in the field have identified several limitations of the study relative to its power and the outcomes studied. This debate illustrates the need for further research regarding identification of patients who are at the greatest risk of recurrence following an episode of idiopathic thromboembolism.