Too Late, or Not Too Late: That Is the Question

We read with great interest the article by Assmann et al,[1] which addresses the important topic of the best timing of coronary artery bypass grafting (CABG) after acute myocardial infarction (AMI). In recent years, the timing of CABG after AMI has always been very challenging. Unnecessary delay as well as early break away has been discussed to expose the patient to access morbidity and mortality.

The authors suggest that CABG early after AMI ( < 10 days) leads to a significant increase in mortality, especially in elderly patients or in patients with a severely impaired left ventricular ejection fraction. The authors then conclude that at least the critical time period of 3 days should be avoided—whenever patients hemodynamic is stable enough.

However, at this point, we have some serious concerns, if the presented data support this conclusion unequivocally. The authors do not differentiate between patients with non-ST-elevation myocardial infarction (NSTEMI) and patients with ST-elevation myocardial infarction (STEMI). The current guidelines recommend the immediate revascularization within 90 minutes after onset of symptoms in patients with STEMI.[2] This recommendation is based on numerous large-scale trials. Of course, these trials did not involve CABG as potential revascularization method but rather fibrinolysis or percutaneous coronary intervention (PCI). Nonetheless, a significant delay of revascularization merely ends with loss of viable myocardium. The design of the study of Assmann and colleagues might easily oversee all those high-risk patients who died on the waiting list to CABG—this may have contributed to the conclusion that patients being operated after a time interval of some days are at significantly lower risk and therefore have a lower mortality.

The situation differs in patients with NSTEMI, which is a heterogeneous population in terms of risk and prognosis. The proportion of patients with NSTEMI undergoing CABG during initial hospitalization is approximately 10% and due to growing life expectancy, this number will increase. Especially low-risk patients benefit from revascularization within 72 hours even in the setting of PCI.[3] Therefore, CABG after a certain time interval seems appropriate.

The effort of addressing this hot topic is highly appreciated. We have to evaluate all comers' data in large prospective trials to learn about the risk of patients who died before the decision for surgery has been made. Until then, we recommend to take the ischemic risk and the clinical situation of each individual patient into account rather than to promote “cooling-down strategies.”

• References

• 1 Assmann A, Boeken U, Akhyari P, Lichtenberg A. Appropriate timing of coronary artery bypass grafting after acute myocardial infarction. Thorac Cardiovasc Surg 2012; 60 (7) 446-451
• 2 Steg PG, James SK, Atar D , et al; Task Force on the management of ST-segment elevation acute myocardial infarction of the European Society of Cardiology (ESC). ESC Guidelines for the management of acute myocardial infarction in patients presenting with ST-segment elevation. Eur Heart J 2012; 33 (20) 2569-2619
• 3 ESC Guidelines for the management of acute myocardial infarction in patients presenting without ST-segment elevation: The Task Force on the management of acute coronary syndromes (ACS) in patients presenting without persistent ST-segment elevation of the European Society of Cardiology (ESC). Eur Heart J 2011; 32: 2999-3054