Introduction 1137 1.1. Methodology and Evidence Review 1137 1.2. Organization of the GWC 1137 1.3. Review and Approval 1137 2. Culprit Artery Only Versus Multivessel PCI 1137 3. Aspiration Thrombectomy 1139 References 1140 Appendix 1. Author Relationships With Industry and Other Entities (Relevant) 1142 Appendix 2. Author Relationships With Industry and Other Entities (Relevant) 1143 Appendix 3. Reviewer Relationships With Industry and Other Entities (Relevant) 2015 Focused Update on Primary Percutaneous Coronary Intervention for Patients With ST-Elevation Myocardial Infarction (Combined Peer Reviewers From 2011 PCI and 2013 STEMI Guidelines) 1145 Preamble To ensure that guidelines reflect current knowledge, avail- able 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 published 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, multilevel review and approval, similar to the full guidelines. 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 Medicine2,3 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 questions, fol- lowed by concise text, with hyperlinks to supportive evidence. 