The Universal Definition of Myocardial Infarction
Authors: Yader Sandoval, Kristian Thygesen, Allan S. Jaffe
Journal: Circulation (2020)

cute myocardial infarction (MI) historically is defined as a clinical syndrome that meets a certain set of criteria, usually a combination of symptoms, electrocardiographic changes, and cardiac biomarkers in the proper clinical context.These criteria have evolved and have been interdigitated with noninvasive and invasive diagnostic imaging and biomarkers.Before 2000, clinicians used a variety of MI definitions.To provide consistency, the Task Force for the Universal Definition of Myocardial Infarction (UDMI) developed international, collaborative, multidisciplinary, consensus definitions to facilitate standardization and a clear nomenclature based on pathophysiology. 1 Although 2 of the authors of the present article were involved in those efforts, our advocacy now reflects our individual concerns with the suggestions made to change the UDMI rather than a feeling that the document cannot be improved.Accordingly, we provide clarification about issues recently raised concerning the UDMI. 2 The UDMI document provides clinical definitions.It is neither a clinical practice guideline nor a clinical decision pathway.Three elements are key.First, it is a pathophysiologic-based scheme.It predicates the diagnosis of acute MI as a clinical syndrome based on common signs and symptoms of acute myocardial ischemia.Finally, recognizing the variability in diagnostic resource availability across the globe, it endorses a definition based on criteria that can be implemented widely.Proposals have been made to modify the UDMI to emphasize the presence or absence of acute coronary obstruction. 2In comparison with the UDMI recommendations, 1 which favor the diagnosis of acute MI as a clinical syndrome, such proposals dichotomize patients with or without acute coronary obstruction and advocate the preeminent use of coronary angiography to determine MI subtypes.Significant problems exist with relying on coronary angiography as the gate keeper.Foremost, it is not routinely available in all hospitals, constraining the ability to diagnose and treat MI, and its broader use among patients with a lower pretest probability for atherothrombosis could lead to more invasive diagnostic procedures and coronary interventions with inherent procedural risks that may not be justified, especially in those with possible type 2 MIs who have comorbidities that increase such risks.Even when available, angiographically complex atherosclerotic lesions and even plaque disruption occur in patients with stable coronary artery disease with intracoronary imaging, 3 which makes unclear what angiographic criteria might be used to define diagnoses.The ACT-2 trial (Appropriateness of Coronary Investigation in Myocardial Injury and Type 2 Myocardial Infarction; URL: https//www.anzctr.org.au; Unique identifier: ACTRN1261800378224) should provide insights into the broader use of coronary angiography, 4 but pending more data, its routine use to determine MI subtypes should not be advised.Some researchers have advocated that conditions leading to acute coronary obstruction other than atherothrombosis, such as coronary embolism, spasm,