第三版心肌梗死定义英文版

Clinical Biochemistry

Volume 46, Issues 1–2, January 2013, Pages 1–4

Third Universal Definition of Myocardial Infarction

Allan S. Jaffe,

Introduction

The Third Universal Definition of Myocardial Infarction (MI) was recently published conjointly by the major cardiology organizations throughout the world and in the journals of the World Health Organization (WHO). This definition builds on two previous two iterations which were developed to make the diagnosis of myocardial infarction (MI) more consistent.

The efforts started originally in 1999 in the conference in Nice stimulated by the innovation of Dr. Kristian Thygesen and Dr. Joseph Albert who had recognized this problem and who developed a task force jointly sponsored by the ACC (American College of Cardiology) and the ESC (European Society of Cardiology) to attempt to standardize the definition of MI [1]. This major step led to the first document which moved the field from the epidemiologically oriented definition of MI which had been developed by the WHO to track the incidence of coronary disease and therefore was oriented towards specificity to a more clinically oriented definition which relied on biomarkers as a key feature of the diagnosis. This resulted in a paradigm shift where the diagnosis required documentation of myocardial necrosis with biomarkers and especially cardiac troponin (cTn) which was emerging at the time in the proper clinical situation. A second iteration in 2007 [2] updated the guidelines and the 2012 definition refines the definition still further particularly as it relates to biomarkers [3] which have in the past decade become progressively more and more sensitive. Intrinsically, increases in sensitivity of this sort tend to result in a diminution of specificity since increasingly sensitive measurements often unmask new etiologies for in this instance, elevations of these sensitive cTn biomarkers.

Areas of the 2012 definition that remains important but unchanged

The definition of MI from the pathologic circumstance obviously is not going to change. The definition mandates the finding of cardiomyocyte necrosis defined

pathologically due to myocardial ischemia. However, the clinical definition since pathology is not readily available to guide clinical care relies on a surrogate marker for cardiac injury; i.e., cardiac biomarkers and particularly, cTn. As in previous iterations, cTn is the biomarker of choice and strongly preferred for the overall guidelines as well as for each specific guideline. The definition of MI from the clinical perspective has not changed substantively. It requires detection of a rise and/or a

fall of a cardiac biomarker, preferably cTn, with at least one value above the 99th percentile reference limit in the appropriate clinical setting (see Table 1 for criteria). There are additional types of MI which will be covered subsequently but the guidelines rely heavily on clinical signs or symptoms, a clinical situation where ischemia is suspected even if signs and symptoms are absent or imaging information suggestive of ischemia in the presence of a changing pattern of elevated biomarkers.

Table 1.

Criteria for acute myocardial infarction (Third Universal Definition of Myocardial Infarction).

➢ Detection of a rise and/or a fall of cardiac biomarker values (preferably cardiac troponin (cTn)) with at least one value above the 99th percentile upper reference limit (URL) and at least one of the following:➢ Ischemic symptoms

➢ ECG changes of new ischemia (new ST–T changes or new LBBB)

➢ Development of pathologic Q waves in the ECG

➢Imaging evidence of new loss of viable myocardium or new regional wall motion abnormality

➢Identification of an intracoronary thrombus by angiography or autopsy Full-size table

Table options

The metrics for the use of these biomarkers remain the same. One needs a value above the 99th percentile of the upper reference limit with a rising and/or a falling pattern of values. However, as cTn assay sensitivity has improved, the ability to consistently operationalize these criteria has become more problematic as will be discussed below. The document also recognizes a variety of special clinical circumstances which require unique handling. Some of these are related to cardiac procedures such as percutaneous interventions (PCI) or coronary artery bypass graft (CABG) surgery but others to novel procedures that are being developed such as transcutaneous aortic valve interventions (TAVI). The document discusses as well subsets of patients who are critically ill, those with heart failure, and those undergoing non-cardiac surgery as well. These classifications are not new from the 2007 document but are considered in greater detail.