ACC/AHA 2004 guideline update for coronary artery bypass graft surgery: summary article. A report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines (Committee to Update the 1999 Guidelines for Coronary Artery Bypass Graft Surgery).

The American College of Cardiology (ACC)/American Heart Association (AHA) Task Force on Practice Guidelines regularly reviews existing guidelines to determine when an update or full revision is needed. This process gives priority to areas where major changes in text, particularly recommendations, are mentioned on the basis of new understanding of evidence. Minor changes in verbiage and references are discouraged. The ACC/AHA Guidelines for Coronary Artery Bypass Graft Surgery published in 1999 have now been updated. The full-text guidelines incorporating the updated material are available on the Internet (www.acc.org or www.americanheart.org) in both a version that shows the changes from the 1999 guidelines in track changes mode, with strike-through indicating deleted text and underlining indicating new text, and a “clean” version that fully incorporates the changes. This article describes the major areas of change reflected in the update in a format that we hope can be read and understood as a stand-alone document. Please note we have changed the table of contents headings in the 1999 guidelines from roman numerals to unique identifying numbers. Interested readers are referred to the full-length Internet version to completely understand the context of these changes. Classification of Recommendations and Level of Evidence are expressed in the ACC/AHA format as follows: ### Classification of Recommendations ### Level of Evidence