To ensure that guidelines remain current, new data are reviewed biannually to determine whether recommen- dations should be modified. In general, full revisions are posted in 5-year cycles. [1] Jonathan L. Halperin, MD, FACC, FAHA Chair, ACC/AHA Task Force on Clinical Practice Guidelines The scope of this focused update is limited to con- siderations relevant to multivessel percutaneous coro- nary intervention (PCI) and thrombus aspiration in Table 1. Applying Class of Recommendation and Level of Evidence to Clinical Strategies, Interventions, Treatments, or Diag- nostic Testing in Patient Care* (Updated August 2015) 1004 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 patients with ST-elevation myocardial infarction (STEMI) undergoing primary PCI. 1.1. Methodology and Evidence Review Clinical trials presented at the major cardiology organizations 2013 to 2015 annual scientific meetings and other selected reports published in a peer-reviewed format through August 2015 were reviewed by the 2011 PCI and 2013 STEMI GWCs and the Task Force to identify trials and other key data that might affect guideline recommendations. The information consid- ered important enough to prompt updated recommenda- tions is included in evidence tables in the Online Data Supplement (http://jaccjacc.acc.org/Clinical_Document/ Supplements.pdf). Consult the full-text versions of the 2011 PCI and 2013 STEMI guidelines [9,10] for recommendations in clinical areas not addressed in the focused update. The individual recommendations in this focused update will be incorporated into future revisions or updates of the full-text guidelines. 1.2. Organization of the GWC For this focused update, representative members of the 2011 PCI and 2013 STEMI GWCs were invited to participate. Members were required to disclose all RWI relevant to the topics under consideration. The entire membership of both GWCs voted on the re- vised recommendations and text. 