[Anticoagulant treatment in atrial fibrillation]

Atrial fibrillation is the most frequent arrhythmia in the general population, and it increases with age. The prevention of thromboembolic events, the most important complication of the disease, is a major problem. Antivitamin K is to date the most efficient therapeutic class for the prevention of these events. Although they allow a decrease in stroke by at least 50%, they are associated with an increased haemorrhagic risk (annual incidence ranging from 7% to 22%). This risk makes oral anticoagulant treatment underused in high risk patients, particularly in the elderly populations. Optimisation of the management of patients with atrial fibrillation should be based on an individual evaluation of the thromboembolic and haemorrhagic risks. Several stratifications have been performed to identify the risk predictors of thromboembolic and haemorrhagic events in patients with atrial fibrillation, allowing an evaluation of the benefit/risk ratio of antithrombotic treatments and using indices such as NNT (number of patients needed to treat to avoid an event) and NNH (number of patients needed to harm with haemorrhagic event). The available data do not allow, however, to evaluate precisely the individual level of haemorrhagic risk.