These statements are reviewed by the Task Force and all members during each conference call and meeting of the writing committee and are updated as changes occur. All guideline recommendations require a confidential vote by the writing committee and must be approved by a consensus of the voting members. Members who recused themselves from voting are indicated in the list of writing committee members, and specific section recusals are noted in Appendix 1. Authors and peer reviewers RWI pertinent to this guideline are disclosed in Appendixes 1 and 2, respectively. Compre- hensive disclosure information for the Task Force is also available online at http://www.cardiosource.org/ACC/About- ACC/Who-We-Are/Leadership/Guidelines-and-Documents- Task-Forces.aspx. The work of the writing committee is supported exclusively by the ACCF, AHA, American College of Physicians (ACP), American Association for Thoracic Surgery (AATS), Preventive Cardiovascular Nurses Associ- ation (PCNA), Society for Cardiovascular Angiography and Interventions (SCAI), and Society of Thoracic Surgeons (STS), without commercial support. Writing committee members volunteered their time for this activity. The recommendations in this guideline are considered current until they are superseded by a focused update or the full-text guideline is revised. Guidelines are official policy of both the ACCF and AHA. Jeffrey L. Anderson, MD, FACC, FAHA Chair, ACCF/AHA Task Force on Practice Guidelines 1.1. Methodology and Evidence Overview The recommendations listed in this document are, whenever possible, evidence based. An extensive evidence review was conducted as the document was compiled through December 2008. Repeated literature searches were performed by the guideline development staff and writing committee members as new issues were considered. New clinical trials published in peer-reviewed journals and articles through December 2011 were also reviewed and incorporated when relevant. 