Troponin assay use in the emergency department for management of patients with potential acute coronary syndrome: current use and future directions

Abstract

Troponins are proteins commonly found in cardiac tissue that are released during myocardial ischemia or necrosis. These troponins can be detected by assays that can then be used to guide clinical decision-making and disposition, especially if the suspected insult is related to acute coronary syndrome. Timing of troponin measurement can be important as elevations may not be detectible immediately after an insult. New assays have been designed to detect troponin con-centrations previously too low to be detected by conventional assays. These tests are known as high-sensitivity cardiac troponin assays. Current research is aimed at evaluating the clinical sig-nificance of troponin elevations detected by these new assays especially in management of pa-tients with suspected acute coronary syndrome. A number of risk-stratification scores exist to assist physicians with evaluating chest pain in the emergency department in the context of de-tection (or absence) of troponins in systemic circulation. Additionally, investigators are working to integrate data generated by hs-cTn measurements into existing and new risk-stratification scores.

Myocardial Infarction in Children

“…After the anamnesis and physical examination, ECG examination must be made in all patients and X-ray imaging should be applied in order to exclude any respiratory causes [15]. In cases where the pain is thought to be of cardiac origin, troponin and creatine kinase myocardial band (CK-MB) levels must be examined and if necessary echocardiographic evaluation should be made [15,17,18].…”

“…An elevation of >2 mm should rouse suspicion of MI (Figures 1 and 2). When ST elevation is determined, there should be a progression through differential diagnosis of benign early repolarisation, pericarditis, MI, bundle branch block and left ventricle aneurism [18]. While pathological ST elevation does not show variability, J point and ST elevation seen in early repolarisation in healthy adults is generally corrected with isoproteronol infusion or exercise [19].…”

“…The presence of PR segment depression is an ECG finding which is valuable in the differentiation of myopericarditis from MI in favour of myopericarditis [18]. The positive predictive value of PR depression seen in chest and extremity derivations has been determined to be 96.7% [19].…”

Non‐coronary predictors of elevated high‐sensitive cardiac troponin T (hs‐cTnT) levels in an unselected emergency patient cohort

“…Also, age has been described as an independent factor for an increasing cTnT, resulting in a median cTnT of 90 ng/L (women) and 75 ng/L (men) at the age of 90 adjusted for comorbidities . Hence, making an appropriate therapy decision can be challenging, especially in the ED setting …”

Examination of troponin testing following implementation of the IMProved Assessment of Chest pain Trial (IMPACT) Protocol, an accelerated chest pain assessment strategy

“…Serial troponin testing is critical for the evaluation of ACS; troponin elevations are seen in multiple chronic cardiac and non-cardiac conditions, but a change in serial troponin levels is indicative of an acute cardiac injury and is an important component of acute myocardial infarction diagnosis. 6,7 This underpins the importance of serial measurement of cardiac troponin. In addition, serum troponin levels are most commonly elevated six to eight hours after myocardial injury, with a peak at twelve to twenty-four hours, and remaining in circulation in the blood for seven to ten days.…”