Predicting outcome in the COURAGE trial (Clinical Outcomes Utilizing Revascularization and Aggressive Drug Evaluation): coronary anatomy versus ischemia

Abstract

Objectives: The aim of this study was to determine the relative utility of anatomic and ischemic burden of coronary artery disease for predicting outcomes.

Background: Both anatomic burden and ischemic burden of coronary artery disease determine patient prognosis and influence myocardial revascularization decisions. When both measures are available, their relative utility for prognostication and management choice is controversial.

Methods: A total of 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 were studied. Several multiple regression models were constructed 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) + percutaneous coronary intervention (PCI) or OMT alone were analyzed.

Results: In nonadjusted and adjusted regression models, anatomic burden and left ventricular ejection fraction were consistent predictors of death, MI, and NSTE-ACS, whereas ischemic burden and treatment assignment were not. There was a marginal (p = 0.03) effect of the interaction term of anatomic and ischemic burden for the prediction of clinical outcome, but separately or in combination, neither anatomy nor ischemia interacted with therapeutic strategy to predict outcome.

Conclusions: In a cohort of patients treated with OMT, anatomic burden was a consistent predictor of death, MI, and NSTE-ACS, whereas ischemic burden was not. Importantly, neither determination, even in combination, identified a patient profile benefiting preferentially from an invasive therapeutic strategy. (Clinical Outcomes Utilizing Revascularization and Aggressive Drug Evaluation [COURAGE]; NCT00007657).

Keywords: angiographic burden; coronary angiography; ischemia; ischemic burden; nuclear perfusion imaging; stable ischemic heart disease.