Title : Troponin ultra and myocardial infarction: Influence of age
Abstract:
Introduction: Cardiac troponins (cTn) play a key role in detecting myocardial necrosis in individuals suspected of having coronary syndrome (ACS). Newer, so-called ultra-sensitive or hypersensitive cTn assays demonstrate excellent sensitivity for diagnosing myocardial infarction (MI). However, elevated cTn concentrations can be found in healthy elderly individuals; furthermore, concentrations in some ultra-sensitive or hypersensitive cTn assays have been shown to correlate with age.
Objectives: To study the influence of age on the diagnostic performance of cardiac troponin I ultra (TNIU) in patients suspected of MI.
Materials and Methods: Serum samples were collected from consecutive patients presenting to the emergency department with chest pain suggestive of myocardial infarction. A total of 42 samples (27 men vs. 15 women) were included in the study. TNIU levels were measured retrospectively using the Minividas analyzer, which combines a two-step sandwich immunoassay with final fluorescence detection (ELFA).The positivity threshold was 0.01 μg/L.
Results: In our study, we noted a male predominance with a sex rao of 1,8. 24 paents were over 65 years old, including 15 men, while 18 were under 65 years old, including 12 men. Plasma concentraons of TNIU are significantly increased in subjects ≥ 65 years (14 posive vs 10 negave) compared to those observed in subjects under 65 years (5 posive vs 13 negave). TNIU concentraons remain significantly elevated in paents with MI compared to those without MI, regardless of age group. Our results confirm that TNIU concentraons are age-dependent.A study by A.S. Bargnoux et al. found that age is the primary factor influencing the 99th percenle value.
The data strongly suggest that the upper reference limit (URL) should be determined in an age-matched populaon. These observaons are supported by previous studies showing a higher opmal cutoff for troponin in older individuals for the diagnosis of MI.
The second factor is sex. Indeed, higher troponin concentraons are generally observed in men in the majority of studies.The third important criterion is how to define the populaon's health status: using a medical history quesonnaire, performing an ECG or cardiac imaging, or adding an esmate of renal funcon.Each of these factors can radically alter the LSR value.
Conclusion: Despite the influence of age on plasma TNIU concentraons, this biomarker remains a highly effecve tool for diagnosing myocardial infarcon in the emergency department. Adjusng the TNIU posivity threshold according to age opmizes the use of this marker: very high sensivity and negave predicve value (NPV), with preserved specificity
