Clinical chemistry
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Cardiac troponins I (cTnI) and T (cTnT) have received international endorsement as the standard biomarkers for detection of myocardial injury, for risk stratification in patients suspected of acute coronary syndrome, and for the diagnosis of myocardial infarction. An evidence-based clinical database is growing rapidly for high-sensitivity (hs) troponin assays. Thus, clarifications of the analytical principles for the immunoassays used in clinical practice are important. ⋯ This review raises important points regarding cTnI and cTnT assays and their reference limits and specifically addresses hs assays used to measure low concentrations (nanograms per liter or picograms per milliliter). Recommendations are made to help clarify the nomenclature. The review also identifies further challenges for the evolving science of cardiac troponin measurement. It is hoped that with the introduction of these concepts, both laboratorians and clinicians can develop a more unified view of how these assays are used worldwide in clinical practice.
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Historical Article
Aspirin in the primary prevention of myocardial infarction.
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Comparative Study
Troponin T measurements by high-sensitivity vs conventional assays for risk stratification in acute dyspnea.
Cardiac troponin T measured by a high-sensitivity assay (hs-cTnT) recently proved to be of prognostic value in several populations. The hs-cTnT assay may also improve risk stratification in acute dyspnea. ⋯ hs-cTnT is associated with mortality in patients presenting with acute dyspnea. hs-cTnT concentrations provide additional prognostic information to cTnT and NT-proBNP testing in patients with cTnT concentrations below the detection limit. In particular, the hs-cTnT cutoff of 0.016 μg/L enables identification of low-risk patients.
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Comparative Study
Comparison of midregional pro-A-type natriuretic peptide and the N-terminal pro-B-type natriuretic peptide for predicting mortality and cardiovascular events.
N-terminal pro-B-type natriuretic peptide (NT-proBNP) provides prognostic information on mortality and future cardiovascular events for individuals from the general population. A novel immunoassay was recently developed that measures a midregional fragment of pro-A-type natriuretic peptide (MR-proANP). We compared the capabilities of MR-proANP and NT-proBNP for predicting mortality and cardiovascular events in a population-based study. ⋯ MR-proANP was as efficient as NT-proBNP in predicting all-cause mortality, cardiovascular mortality, and cardiovascular events; however, its association with cardiovascular mortality was not independent from other confounders.
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Most outcome studies of patients presenting early to the emergency department with potential acute coronary syndromes have focused on either the index diagnosis of myocardial infarction (MI) or a composite end point at a later time frame (30 days or 1 year). We investigated the performance of 9 biomarkers for an early serious outcome. ⋯ The optimal cutoffs for predicting serious cardiac outcomes in this low-risk population are different from the published 99th percentiles. Larger studies are required to verify these findings.