Relationship between procedure indications and outcomes of percutaneous coronary interventions by American College of Cardiology/American Heart Association Task Force guidelines

Background: An American College of Cardiology/American Heart Association (ACC/AHA) Task Force periodically revises and publishes guidelines with evidence-based recommendations for appropriate use of percutaneous coronary intervention (PCI). Some studies have suggested that closer adherence to guidelines can reduce variations in care, can improve quality, and may ultimately result in better outcomes, but this finding is incompletely understood. Guidelines themselves must change to be responsive to continuously evolving clinical practice. Our goal here was to investigate whether any relationship existed between the most recent ACC/AHA recommended indications for PCI and short term in- hospital outcomes. Methods and Results: We analyzed the ACC National Cardiovascular Data Registry for the period of January 1, 2001, through March 31, 2004. We excluded PCI procedures performed for acute myocardial infarction (ST- segment elevation myocardial infarction); all others were grouped by their indications according to the standard ACC/AHA scheme: Class I, evidence and/or agreement that PCI is useful and effective; Class IIa, conflicting evidence and/or divergent opinions, weight is in favor; Class IIb, usefulness/efficacy is less well established; and Class III, evidence and/or agreement that PCI is not useful or effective and may be harmful. Clinical success was defined as angiographic success (< 20% residual stenosis) at all lesions attempted without the adverse events of myocardial infarction, same- admission bypass surgery, or death. There were 412 617 PCI procedures included in the analysis. Frequency of indications was as follows: Class I, 64%; Class IIa, 21%; Class IIb, 7%; and Class III, 8%. Clinical success declined across the indications classes (92.8%, 91.7%, 89%, and 85.5%, respectively; P < 0.001), whereas adverse events increased. Conclusions: In this large survey of contemporary PCI practice, most procedures were performed for Class I indications. A significant relationship between evidence-based indications recommended by the ACC/AHA Task Force and in-hospital outcomes was noted.