Troponin Criteria for Myocardial Infarction After Percutaneous Coronary Intervention

Abstract

Myocardial infarction (MI) after percutaneous coronary intervention (PCI) is an important safety event, and rates of periprocedural MI are included as a component of the primary end point in clinical trials of coronary stents and other device and pharmacologic therapies for coronary artery disease.^1,2 There is no longer debate about whether mild elevations in creatine kinase (CK) or its specific MB (CKMB) isoform after these procedures represent myocardial necrosis³ or that levels of these enzymes that correlate with larger infarct size or occur after unsuccessful procedures are clearly associated with increased early and late mortality.^4,5 There does remain controversy regarding the prognostic importance of lower-level biomarker elevations, particularly after otherwise successful procedures.^6,7 Indeed, available data remain inadequate to establish a definitive threshold for clinically important biomarker elevations. A recent global task force report⁸ on the universal definition of MI suggested a threshold of 3 times the 99th percentile of the upper reference limit for CKMB or troponin (I or T) to define MI after PCI, with a preference for the use of troponin.