Dynamic stroke risk scores of atrial fibrillation

Atrial fibrillation (AF) is associated with a nearly five-fold increased risk of ischemic stroke, and that 1 in 5 cases of stroke can be attributed to this arrhythmia (1-3). Stroke prevention is a major priority in the clinical management of AF. When compared to control/placebo, oral anticoagulation (OAC) therapy reduces the risk of stroke by 64% and the risk of death by 26% (4), but it can cause hemorrhage (4,5). Thus, the decision to prescribe anticoagulant therapy to patients with AF depends on these risks. Current guidelines recommend OAC for stroke prevention of AF patients unless they are deemed to be at low risk of stroke (6-9). Given that OAC also increases bleeding risk (which can be fatal), OAC therapy should be decided on the basis of the expected net clinical benefit of OAC therapy. Therefore, stroke risk stratification is a critical step, and an annual stroke risk of 1–2% is considered as the threshold at which OAC therapy yields a net clinical benefit (10,11)