For more on AHA state- ments and guidelines development, visit http://my.americanheart. org/statements and select the Policies and Development link. Permissions: Multiple copies, modification, alteration, enhance- ment, and/or distribution of this document are not permitted without the express permission of the American Heart Association. Instruc- tions for obtaining permission are located at http://www.heart.org/ 04_Article.jsp. A link to the Copyright Permissions Request Form appears on the right side of the page. Published online 9 May 2016 in Wiley Online Library (wileyonline- library.com) 1002 Levine et al. Catheterization and Cardiovascular Interventions DOI 10.1002/ccd. Published on behalf of The Society for governed by the applicable Creative Commons License Key words: ACC/AHA Clinical Practice Guideline; focused update; culprit vessel; multivessel; myocardial infarction; pri- mary PCI; thrombectomy PREAMBLE To ensure that guidelines reflect current knowledge, available treatment options, and optimum medical care, existing clinical practice guideline recommendations are modified and new recommendations are added in response to new data, medications or devices. To keep pace with evolving evidence, the American College of Cardiology (ACC)/American Heart Association (AHA) Task Force on Clinical Practice Guidelines ( Task Force ) has issued this focused update to revise guide- line recommendations on the basis of recently pub- lished data. This update is not based on a complete literature review from the date of previous guideline publications, but it has been subject to rigorous, multi- level review and approval, similar to the full guide- lines. For specific focused update criteria and additional methodological details, please see the ACC/ AHA guideline methodology manual. [1] MODERNIZATION In response to published reports from the Institute of Medicine [2,3] and ACC/AHA mandates, [4 7] processes have changed leading to adoption of a knowledge byte format. This entails delineation of recommendations addressing specific clinical ques- tions, followed by concise text, with hyperlinks to supportive evidence. 