Clinical Relevance of Troponins Measurement
المؤلف:
Marcello Ciaccio
المصدر:
Clinical and Laboratory Medicine Textbook 2021
الجزء والصفحة:
p297
2025-08-31
329
In recent years, the development of detection methods for cTnI and cTnT with progressively increasing analytical sensitivity, which can detect myocardial necrosis of microscopic size, has led to a revolution in the definition of acute myocardial infarction. According to the latest definition of myocardial infarction, the measurement of cardiac troponin plays a central and essential role in its diagnosis.
his new definition of AMI is having a significant clinical (but also social and economic) impact, as, since its introduction, diagnosed cases of infarction have increased by 20–40%, compared with when the World Health Organization (WHO) definition of AMI, published in 1973, was used. The WHO definition considered three distinct criteria for the diagnosis of myocardial infarction:
• The presence of typical ischemic symptoms
• The presence of typical electrocardiographic signs
• The typical upward/downward trend in the values of the so-called cardiac enzymes (AST, CK, and LDH).
However, only two of these three criteria were necessary for the diagnosis. According to this definition, in a patient with typical symptoms (anginal pain) and electrocardiographic (ECG) alterations (such as ST-segment elevation), the IMA diagnosis is established. In patients with ST-segment elevation myocardial infarction (STEMI), the cTnI or cTnT assay can only confirm the diagnosis and be used for monitoring and prognosis. The cardiac troponins measurement becomes essential for diagnosing patients with typical ischemic symptoms without ECG alterations; in these patients, if they have an altered troponins kinetics, a diagnosis of non ST elevated myocardial infarction (NSTEMI) is made.
The most evident and relevant clinical advantage of the new methods for measuring cTnI and cTnT with higher analytical sensitivity is the reduction of the time required to diagnose AMI. Indeed, from diagnostic algorithms based on serial sampling on admission and after 12–24 hours by the first generation methods (1990–2002), there has been a gradual shift to more rapid diagnostic algorithms (6–12 hours in the years 2003–2007), which, by methods at high analytical sensitivity, require a second sampling 3 hours after admission (Fig. 1). Finally, in the European Society of Cardiology (ESC) guidelines published in 2015, and subsequently updated in 2018, an assessment of biomarker kinetics involving a second sampling (T1) after 1 hour is suggested.
Fig1. Algorithm for diagnosing acute myocardial infarction (AMI) in accordance with national guidelines. 3-hour algorithm for the diagnosis of IMA NSTEMI, using a highly sensitive measurement method. Ischemic setting: patient with medium-high risk of the acute coronary syndrome, without a pathognomonic ECG for STEMI. The diagnosis of NSTEMI is ascertained when at least in a sample collected within 3 hours of admission, a troponin (Tn) value higher than the 99th percentile of the reference population is found and the change from the base line value (admission to the Emergency Department) is greater than 50%. (Copyright EDISES 2021. Reproduced with permission)
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