Major bleeding included intracranial bleeding, the most severe and disabling form of anticoagulant-related bleeding. Literature Searches and Study Selection To inform our guideline development, we searched for relevant articles published since the last formal literature search performed for the Antithrombotic and Thrombolytic Therapy: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines (9th Edition), which were published in 2012.3 Searches were also conducted speci cally for existing guidelines and systematic reviews. In cases in which existing, good quality systematic review(s) were retrieved, the results of the review informed our recommendations. Speci cally, for literature regarding the assessment of stroke risk in patients with AF, we searched MEDLINE via PubMed and the Cochrane Library for articles published from October 2009 to October 2017 using the search terms atrial brillation, atrial utter, risk assessment, risk factors, risk strati cation, stroke, and thromboembolism. For literature regarding prevention of stroke and thromboembolism in patients with AF, we searched MEDLINE via PubMed and the Cochrane Library for articles published from January 1, 2007, to October 2017 using the search terms coumarins, warfarin, dicumarol, phenprocoumon, acenocoumarol, fondaparinux, idraparinux, aspirin, tri usal, indobufen, dabigatran, ximelagatran, rivaroxaban, apixaban, ticlopidine, clopidogrel, catheter ablation, watchman, PLAATO, cardioversion, atrial brillation, and atrial utter. Titles and abstracts of the search results were reviewed independently and in parallel to identify potentially relevant articles based on the inclusion and exclusion criteria from the PICO elements. Discrepancies were resolved by discussion. Studies deemed eligible then underwent a second round of full-text screening following the same methodology used during title/abstract review. Important data from each included study were then extracted into structured evidence tables. Risk of Bias Assessment The methodologist assessed the risk of bias in all included studies. 