Advances in stroke prevention in atrial fibrillation: enhanced risk stratification combined with the newer oral anticoagulants.

Patients with atrial fibrillation (AF) have an increased stroke risk compared with those in sinus rhythm, although the absolute risk for individual patients is modulated by the presence of various additional risk factors. Patient selection for oral anticoagulation for stroke prevention is based on risks of stroke and bleeding. Although CHADS2 (congestive heart failure, hypertension, age ≥75 years, diabetes mellitus, stroke or transient ischemic attack) is the most widely used scheme for evaluating stroke risk in patients with AF, several other stroke risk factors are not included; therefore, many patients' stroke risk may be underestimated, contributing to the underuse of anticoagulants. Furthermore, a substantial proportion of patients are categorized as being at moderate risk (CHADS2 = 1), and there has been some ambiguity regarding optimum thromboprophylaxis in this group. The refinement of CHADS2 , CHA2 DS2 -VASc (Congestive heart failure, Hypertension, Age 75 years [2 points], Diabetes mellitus, Stroke or transient ischemic attack [2 points], Vascular disease, Age 65 to 74 years, Sex category [female]), considers additional risk factors. Its main advantage is its ability to identify patients truly at low risk of thromboembolism (CHA2 DS2 -VASc = 0), who are unlikely to benefit from antithrombotic therapy. For all others, an oral anticoagulant may be the preferred approach, simplifying clinical decision making. Implementation of CHA2 DS2 -VASc may also result in an increased proportion of patients receiving anticoagulation. The emergence of newer oral anticoagulants that can be given without routine coagulation monitoring, with improved benefit-risk profiles vs vitamin K antagonists, promises to simplify therapy for patients with AF at risk of stroke. This, coupled with advances in stroke risk stratification, is expected to improve patient outcomes and reduce the burden of AF-related stroke.