Oral anticoagulation in venous thromboembolism: decisions based on more than mere feelings.

Although there is a very limited scientific basis for the recommendation to target the intensity of oral anticoagulation after venous thromboembolism at an international normalized ratio (INR) of 2.0-3.0, this has been widely adopted. It seems possible from the DURAC I and II trials that a slight lowering of the upper limit could further reduce the risk of major haemorrhage. The optimal duration of anticoagulation in this group of patients has been extensively investigated. For the majority of patients a treatment duration of 6 months eliminates the high risk of relatively early recurrences without yielding an increase in the incidence of major haemorrhages. Patients with a distal deep vein thrombosis and a temporary risk factor or those with poor compliance should have a shorter treatment duration, whereas further prolongation is warranted in patients with certain biochemical abnormalities or recurrent thromboembolic episodes. The optimal treatment regimen is individualized, taking into account a variety of risk factors, and re-evaluated regularly in case of prolonged therapy.