Stroke risk stratification scores in atrial fibrillation: current recommendations for clinical practice and future perspectives

Atrial fibrillation (AF) increases the risk of stroke. This additional risk varies depending on the presence of various clinical risk factors. The contribution of some risk factors, for example vascular disease and female gender, has been disputed. Stroke risk stratification scores (RSS) incorporate these risk factors to identify patients at different levels of stroke risk. These RSS enable the targeting of oral anticoagulants (OAC) at high-risk patients, who stand to gain the most in terms of stroke risk reduction, and avoidance of their use in low-risk patients, in whom the harms of OAC (increased risk of bleeding) may outweigh their stroke prevention capabilities. Guidelines on the management of AF have used and adapted various RSS for this purpose, and have tailored their therapeutic recommendations around the different risk categories. Current guidelines advocate the use of the CHA₂DS₂-VASc RSS to assess stroke risk in AF patients, to identify truly low-risk patients (men and women aged <65 years with no risk factors) who may not require antithrombotic therapy, with consideration of OAC for all other patients. The recent development of novel OACs is changing the risk threshold at which it is acceptable to treat AF patients. However, consideration of OAC therapy for stroke prevention also requires assessment of the associated bleeding risk and incorporation of patients' preferences when making treatment decisions.