[Bleeding, the Achilles' heel in patients treated with anticoagulants. Approach in patients with atrial fibrillation].

Bleeding is always the Achilles' heel of all antithrombotic therapy, being unthinkable to use this type of therapy ignoring the complications that it may arise. The bleeding risk raises very particular problems, namely how to predict it and how to manage it. The withdrawal of antithrombotic drugs and transfusion are two important practical problems, involving clinical decisions that are generally very difficult. The new oral anticoagulants pose new problems. If on the one hand its bleeding risk appears to be less, specially in what concerns intracranial bleeding and potentially life-threatening bleeding, on the other hand the lack of an antidote or the lack of a quick and effective laboratory test to evaluate its efficacy, are arguments used by the critics. The risk of bleeding is conditioned by several factors, among them old age. The elderly patient is, by definition, the patient that can bleed more but also the one that, due to its ischemic risk, can reap more benefit. In this paper some of the tools used to predict the risk of bleeding and its clinical impact are also presented.