Redefining myocardial infarction following coronary revascularization: time for clarity?

Myocardial infarction (MI) after coronary revascularization is very common and, at this time, we still do not have a clear definition. The universal definition for MI was published in 2007 and was revised in 2012. However, it has a lot of shortcomings and has not been correlated with clinical outcomes or prognostic significance. This definition used a postprocedural biomarker for defining percutaneous coronary intervention (PCI)-related MI (type 4a) and coronary artery bypass grafting (CABG)-related MI (type 5). cTn was recommended as the biomarker of choice, even though the prognostic significance of cTn is less well validated than CK-MB. Assessment of post-PCI and -CABG biomarkers that are strongly related to subsequent adverse patient outcomes is clearly worthwhile. However, applying undue significance to periprocedural biomarker elevations without prognostic relevance will result in unintended consequences on patient care, and physician and systems quality evaluation. Elevated cardiac biomarkers, even after successful revascularization, can lead to prolonged hospital stay and unnecessary interventions. This, in turn, will result in iatrogenic complications and increased cost burden. Adoption of a MI definition not based on a meaningful correlation with adverse consequences in clinical trials may result in false conclusions and treatment options. Hence, it is time to determine a clearer and better definition that is clinically more relevant. In 2007, a ‘universal definition’ for MI following coronary revascularization was proposed [1] and was recently revised in 2012 [2]. In this document, a PCI-related MI (type 4a) was defined as an increase in cTn to more than five-times the 99th percentile of the upper reference limits during the first 48 h following PCI (in patients with