The paradoxical use of cardiac catheterization in patients with non-ST-elevation acute coronary syndromes: lessons from the Can Rapid Stratification of Unstable Angina Patients Suppress Adverse Outcomes With Early Implementation of the ACC /AHA Guidelines (CRUSADE) Quality Improvement Initiative.

Background: The long-term benefits of coronary revascularization are proportional to the severity of underlying coronary artery disease (CAD). We sought to identify patients with a greater probability of severe CAD to target those who could receive the greatest benefit from revascularization.
Methods: We used multivariable logistic generalized estimating equations modeling to identify clinical factors associated with severe CAD in 83,490 patients, without prior bypass surgery, who underwent coronary angiography after presenting with non-ST-segment elevation acute coronary syndromes enrolled in CRUSADE. We then compared actual patterns of cardiac catheterization use relative to patients' probability of severe CAD in those who underwent catheterization and those who did not.
Results: Independent factors associated with severe CAD included older age, male sex, diabetes, no prior percutaneous coronary intervention, signs or history of heart failure, prior myocardial infarction, ST-segment depression, and family history of CAD. Cardiac catheterization rates were inversely related to the probability of severe CAD as estimated by the model.
Conclusions: There is a misalignment in the use of cardiac catheterization in patients with non-ST-segment elevation acute coronary syndromes relative to their predicted probability of severe CAD. The use of catheterization appears to target patients who would derive less benefit from revascularization. Further quality improvement efforts should promote appropriate use of cardiac catheterization procedures among patients with the greatest potential benefit.