Prevention of thromboembolic complications in patients with atrial fibrillation

Atrial fibrillation (AF) is a major arrhythmia in clinical practice, and its frequency rises rapidly from the sixth decade onward. Its most serious clinical consequence is ischemic stroke. Patients with AF have a five-fold increased risk of stroke compared to those in sinus rhythm. Advancing age, prior stroke or transient cerebral ischemia, diabetes, hypertension, and impaired function of the left ventricle are known risk factors. On the basis of data from several randomized controlled clinical trials and pooled analyses, several guidelines have been published to promote the use of anticoagulant treatment to prevent stroke in patients with AF. The management of oral anticoagulant therapy needs regular monitoring of INR, which should be kept in the narrow therapeutic range of 2.0-3.0 most of the time, with adjustments of the dose as required. Only a small proportion of patients with AF whom best-practice guidelines identify as eligible for oral anticoagulant therapy actually receive it. Inconvenience of monitoring and frequent dose adjustments, together with fear of major hemorrhage associated with oral anticoagulants, contribute to this underuse. In particular, conventional intensity of anticoagulation increases the risk of intracranial hemorrhage, and patients with advanced age are more prone to cerebral bleeding than younger patients. Up to date, the efficacy of aspirin, an antiplatelet agent, for stroke prevention in AF patients is less clear and remains controversial and alternative pharmacological treatment options have failed to demonstrate their superiority over vitamin K antagonists.