Letter by Tarantini et al Regarding Article, “Optimal Medical Therapy With or Without Percutaneous Coronary Intervention to Reduce Ischemic Burden: Results From the Clinical Outcomes Utilizing Revascularization and Aggressive Drug Evaluation (COURAGE) Trial Nuclear Substudy”
To the Editor:
In the nuclear substudy of the Clinical Outcomes Utilizing Revascularization and Aggressive Drug Evaluation (COURAGE) trial, Shaw et al1 showed that adding percutaneous coronary intervention (PCI) to optimal medical therapy (OMT) resulted in a greater reduction in ischemia than did OMT alone. Moreover, they also found that the magnitude of residual ischemia on follow-up was proportional to the risk of death or myocardial infarction, and a ≥5% reduction in ischemia was associated with a significant reduction in risk. At adjusted analysis, the authors failed to find an independent treatment effect on these results.
A closer look at their report suggests that some points deserve further comments to avoid misleading readers and to clarify the clinical implications of the study. At baseline, moderate-to-severe ischemia at myocardial perfusion single photon emission computed tomography was present only in one third of cases. At follow-up, although a higher percentage of the patients in the PCI+OMT group had no inducible ischemia (15% versus 9%; P=0.06), as few as 33% of the PCI+OMT patients had a significant reduction in ischemia ≥5% at myocardial perfusion single photon emission computed tomography compared with 20% in OMT patients. This point is evident if we consider that two third of the patients had at least 2-coronary vessel disease and that for patients randomized to PCI, no data exist on the rate of complete revascularization. In patients with stable multivessel coronary artery disease, the identification of the target lesion may be troublesome. In the study by Shaw et al,1 the rate of patients free from angina was not significantly different between the PCI+OMT and OMT groups at follow-up. Maintaining the relationship between event-free survival and reduction in ischemic myocardium, we think that the failure to appreciate a striking treatment effect of PCI+OMT in reducing cumulative event free-survival compared with OMT might be related to both the relative low ischemic burden of the population at baseline as well as to incomplete revascularization at the time of PCI. We wonder whether OMT could remain “not inferior” to complete revascularization by PCI even at higher levels of ischemic burden.
Shaw LJ, Berman DS, Maron DJ, Mancini GBJ, Hayes SW, Hartigan PM, Weintraub WS, O'Rourke RA, Dada M, Spertus JA, Chaitman BR, Friedman J, Slomka P, Heller GV, Germano G, Gosselin G, Berger P, Kostuk WJ, Schwartz RG, Knudtson M, Veledar E, Bates ER, McCallister B, Teo KK, Boden WE; COURAGE Investigators. Optimal medical therapy with or without percutaneous coronary intervention to reduce ischemic burden: results from the Clinical Outcomes Utilizing Revascularization and Aggressive Drug Evaluation (COURAGE) trial nuclear substudy. Circulation. 2008; 117: 1283–1291.