DISCLAIMER: CHEST Guidelines are intended for general information only, are not medical advice, and do not replace professional medical care and physician advice, which should always be sought for any medical condition. The complete disclaimer for this guideline can be accessed at: http://www.chestnet.org/Guidelines-and-Resources FUNDING/SUPPORT: This study was funded in total by internal funds from the American College of Chest Physicians. CORRESPONDENCE TO: Gregory Y.H. Lip, MD, Liverpool Centre for Cardiovascular Science, University of Liverpool and Liverpool Heart and Chest Hospital, Liverpool, United Kingdom; e-mail: gregory.lip@ liverpool.ac.uk Copyright 2018 American College of Chest Physicians. Published by Elsevier Inc. All rights reserved. 1122 Evidence-Based Medicine [ 1 5 4 # 5 C H E S T N O V E M B E R 2 0 1 8 ] patients with one or more non-sex CHA2DS2-VASc stroke risk factors (score of 1 in a male or 2 in a female) (Strong recommendation, moderate quality evidence). Remark: Consideration of other less established clinical stroke risk factors, imaging (cardiac or cerebral), or biomarkers (urine, blood, or genetics) may re ne risk strati cation based on simple clinical factors. A complex risk schema using a variety of such data that could accurately place more patients in the low risk stratum not requiring anticoagulants than current simple clinically based scores (personalized medicine) should be the goal of future research, but it will be very dif cult to nd non- anticoagulated patient cohorts for prospective validation. 3. For patients with AF, we recommend bleeding risk assessment should be performed for all patients with AF at every patient contact and should initially focus on potentially modi able bleeding risk factors (Strong recommendation, low quality evidence). 