Original title: Predicting Outcome in the COURAGE Trial. Coronary Anatomy Versus Ischemia. Reference: G. B. John Mancini et al. J Am Coll Cardiol Intv 2013, Article in press.
Anatomical risk, ischemic amount or a combination of both, are often factors taken into account for estimating the prognosis or choose a treatment strategy. The COURAGE study (Clinical Outcomes Utilizing Revascularization and Aggressive Drug Evaluation) showed no inferiority between the initial strategy of optimal medical therapy plus coronary angioplasty versus optimal medical treatment alone, to prevent events such as death or myocardial infarction. A substudy of the latter based on the results of SPECT (single – photon emission computed tomography ) showed that the group receiving angioplasty showed a greater reduction in ischemic amount so that, in theory , the latter could be a benefit predictor of an initial invasive strategy. Given the above data, the purpose of this study was to evaluate the power of ischemic amount and coronary anatomy in predicting death, myocardial infarction or acute coronary syndromes without ST segment elevation and secondly to determine whether the combination of this information could help to identify patients who initially benefit from an invasive strategy. Given the design of COURAGE, no patient with a lesion in left coronary trunk was included.
A total of 621 patients were analyzed, those who had SPECT data and baseline angiography reaching a monitoring of 4.69 ± 1.68 years. In this period a total of 185 events were observed (death/myocardial infarction/acute coronary syndromes without ST segment elevation) which corresponds to 29.8 % of the population. This cohort analyzed and compared to the overall population of COURAGE had significantly more risk factors such as hypertension, diabetes, previous myocardial revascularization surgery, 3-vessel disease, among others. All these factors were used to make adjustments in the logistic regression models used. Only the anatomical risk and ventricular ejection fraction were consistent predictors of death/ myocardial infarction/ acute coronary syndromes without ST segment elevation while the ischemic amount or the allocated treatment were not. A marginal effect for the interaction between ischemic and anatomical risk (p = 0.03) to predict events was observed, however, neither of them (together or separately) modified the prognosis when related it to treatment strategy.
Conclusion:
In this cohort of patients in the COURAGE anatomical risk was a consistent predictor of death, myocardial infarction, and acute coronary syndromes without ST segment elevation unlike ischemic amount. Neither separately nor even in combination were able to identify patients who might benefit from initial invasive strategy.
Editorial comment
These data suggest that the ischemic amount would have more relevance to those with a larger amount of atherosclerotic disease, which gives an important justification for the current study ISCHEMIA (International Study of Comparative Health Effectiveness with Medical and Invasive Approaches). Many questions of this sub-study should be clarified when the previous work become published.
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