Abstract
Background and aim: The large number of publications on the role of troponin testing in the setting of patients with suspected acute coronary syndrome, in patients with stable angina, in patients with comorbidities, and in elderly residents makes it difficult to determine what to do (which troponin test), in what patients (acute or chronic coronary disease), and in which setting (testing in the ambulance, emergency department or Intensive Care Unit). The development of point-of-care troponin I and T tests has opened the door for early testing, but testing too early will conflict with the “troponin blind interval”. The recent improvements of analytical sensitivity of point-of-care troponin tests have created a vast number of new situations in which an early generated troponin result may lead to rapid diagnosis (in conjunction with ECG, anginal complaints, and physical examination) and rapid “rule in” or “rule out” decisions, which will lead to less admissions to the emergency department, less diagnostic activities like imaging procedures, and less costs of clinical care.
Methods: This review addresses developments of this field in the past 10 years since we asked the question “Will future troponin measurement overrule the ECG as the primary diagnostic tool in patients with acute coronary syndrome?”1
Findings: The sensitivity and reliability of the cardiac troponin I or T tests, including point-of-care cardiac troponin I or T tests, have been improved to a level that is indicated by the indication “high-sensitivity” (hs). These tests make it possible to determine cardiac troponin I or T values (i) in ≥50% of blood samples of healthy individuals, (ii) in blood samples of patients with acute myocardial infarction of very recent origin, (iii) in blood samples that show a rise of cardiac troponin I or T levels, and (iiii) in blood samples that show a fall of cardiac troponin I or T levels. An interesting development is the use of a second biomarker, of which copeptin is a promising adjunct. Instead of a second biomarker, clinicians are assisted by employing acute coronary syndrome scoring systems (such as the HEART score), for instance, to identify patients with low risk. The issue of specificity of elevated cardiac troponin I or T levels for acute myocardial infarction is scrutinized.
Conclusion: We conclude this review by stating that for patients with suspected acute coronary syndrome the protocols are refined for how and when to use cardiac troponin I or T tests for (i) prehospital triage to rule out low risk patients, and (ii) in hospital risk assessment of (very) high risk patients, including anamnesis, physical examination, and ECG. The continuing development of cardiac troponin tests improves the quality of diagnosis and shortens the interval to diagnosis and subsequent discharge from hospital, leading to less further clinical assessments, and less health care costs. In general, any new biomarker test should comply with filling in existing gaps in clinical care.