Optimal duration of anticoagulation in patients with unprovoked venous thromboembolism: the impact of novel anticoagulants.

Once anticoagulation is stopped, the risk of recurrent venous thromboembolism (VTE) over years approaches 50% of all patients with a first episode of unprovoked VTE. The persistence of residual vein thrombosis at ultrasound assessment has consistently been shown to increase the risk, as do persistently high values of D-dimer. Although the latest international guidelines suggest indefinite anticoagulation for most patients with the first episode of unprovoked VTE, strategies that incorporate the assessment of residual vein thrombosis and D-dimer have the potential to identify a substantial proportion of subjects in whom anticoagulation can be safely discontinued. For those patients in whom anticoagulation cannot be discontinued, new opportunities are offered by the availability of low-dose anti-Xa compounds, which have been found to possess an extremely favourable benefit/risk profile.