The optimum length of anticoagulation therapy after venous thromboembolism - universal or individualised approach?

Long-term peroral anticoagulation treatment is indicated after a thromboembolic event. The length of treatment should be based on balancing the risk of recurrence against the risk of bleeding complications. The minimum period of treatment is 3 months and can be reduced in certain cases; however, for many patients, a longer period of treatment may be recommendable. The presence or absence of a provoking factor and the nature of such a factor are of primary relevance when deciding on the length of treatment. Patients after a thromboembolic event provoked by a transitory (reversible) risk factor (surgery, accident, estrogen treatment etc.) have a very low risk of recurrence and a three-month treatment period is sufficient for them. In the remaining cases, extended treatment is recommendable, spanning from 6 to 12 months minimally. The type and scope of the event and the number of possible previous events should also be considered. Patients with a malignancy have a higher risk of recurrence and benefit most from long-term therapy with low-molecular weight heparin. Male sex, some thrombophilias and, according to some studies, the presence of residual thrombus in the vein, all increase the risk of recurrence. D-dimer detection results may also be useful in determining treatment length. They should be measured both before discontinuation of treatment and, more importantly, one month after treatment termination. A negative result in the D-dimer detection test means that there is a very low recurrence risk whilst a positive result indicates high risk of recurrence, in which case renewal of anticoagulation therapy should be considered. Deciding on the length of therapy is a complex process and should involve interdisciplinary cooperation.

Keywords: thromboembolic disease; deep venous thrombosis; pulmonary embolism; anticoagulant treatment; recurrence; risk factor