Predicting Outcome in the COURAGE Trial: Coronary Anatomy Versus Ischemia

Study Questions:

What is the prognostic impact of ischemic burden and extent of coronary artery disease?

Methods:

The authors used data from 621 patients enrolled in the COURAGE (Clinical Outcomes Utilizing Revascularization and Aggressive Drug Evaluation) trial with baseline quantitative nuclear single-photon emission computed tomography (SPECT) and quantitative coronary angiography. Several regression models were developed to determine independent predictors of the endpoint of death, myocardial infarction (MI; excluding periprocedural MI), and non–ST-segment elevation acute coronary syndromes (NSTE-ACS). Ischemic burden during stress SPECT, anatomic burden derived from angiography, left ventricular ejection fraction, and assignment to either optimal medical therapy (OMT) and percutaneous coronary intervention (PCI) or OMT alone were analyzed.

Results:

Anatomic burden and left ventricular ejection fraction predicted death, MI, and NSTE-ACS, in both nonadjusted and adjusted regression models, whereas ischemic burden and treatment assignment did not. There was a marginal (p = 0.03) interaction between anatomic and ischemic burden for the prediction of clinical outcome, but neither anatomy nor ischemia interacted with revascularization to predict outcome.

Conclusions:

Among patients treated with OMT, anatomic burden was a consistent predictor of death, MI, and NSTE-ACS, whereas ischemic burden was not.

Perspective:

Current guidelines and appropriate use criteria are heavily weighted toward using ischemic burden to guide revascularization, and this study adds to the small, but growing body of data that is challenging this construct (Panza, J Am Coll Cardiol 2013;61:1860-70).The ongoing ISCHEMIA trial is evaluating the role of ischemia-guided revascularization for stable coronary artery disease, but the utility of revascularization for asymptomatic stable disease is increasingly appearing questionable.

Clinical Topics: Acute Coronary Syndromes, Invasive Cardiovascular Angiography and Intervention, Noninvasive Imaging, Interventions and ACS, Interventions and Imaging, Angiography, Computed Tomography, Nuclear Imaging

Keywords: Myocardial Infarction, Acute Coronary Syndrome, Coronary Angiography, Ventricular Function, Left, Tomography, Emission-Computed, Single-Photon, Percutaneous Coronary Intervention


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