Comparison of Contemporary Troponin Assays With the Novel Biomarkers, Heart Fatty Acid Binding Protein and Copeptin, for the Early Confirmation or Exclusion of Myocardial Infarction in Patients Presenting to the Emergency Department With Chest Pain

Study Questions:

What is the diagnostic accuracy of novel biomarkers of myocardial injury and troponin assays for diagnosis of myocardial infarction?

Methods:

A total of 850 patients randomized to the point-of-care testing arm of the RATPAC (Randomized Assessment of Panel Assay of Cardiac markers) study in six emergency departments of low-risk patients presenting with chest pain were studied. Blood samples were obtained on admission and 90 minutes from admission. Myocardial infarction was defined by the universal definition of myocardial infarction. The following diagnostic strategies were compared by receiver operator characteristic curve analysis and comparison of area under the curve: individual marker values and the combination of presentation heart fatty acid binding protein (HFABP) and copeptin with troponin.

Results:

A total of 68 patients had a final diagnosis of myocardial infarction. Admission samples were available from 838/1,132 patients enrolled in the study. Areas under the curve were as follows (confidence intervals in parentheses): cardiac troponin I (cTnI) Stratus CS 0.94 (0.90-0.98), cTnI Beckmann 0.92 (0.88-0.96), cTnI Siemens ultra 0.90 (0.85-0.95), cTn T high-sensitivity 0.92 (0.88-0.96), HFABP 1 0.84 (0.77-0.90), copeptin 0.62 (0.57-0.68). HFABP and copeptin were diagnostically inferior to troponin. The combination of HFABP (at the 95th percentile) and troponin (at the 99th percentile) increased diagnostic sensitivity.

Conclusions:

The authors concluded that high-sensitivity cTn is the best single marker.

Perspective:

The current study is the first to directly compare sensitive troponin assays directly with each other, with HFABP and copeptin in the low-risk emergency department chest pain population. Overall, the measurement of cTn I was the single best test. Even sensitive troponin measurements are unable on their own to diagnose acute myocardial infarction very early with 100% sensitivity, but come close, suggesting that very rapid rule out is possible. Further studies combining sensitive troponin with clinical assessment or HFABP are indicated to assess diagnostic sensitivity.

Clinical Topics: Dyslipidemia, Lipid Metabolism

Keywords: Fatty Acid-Binding Proteins, Myocardial Infarction, Diterpenes, Biological Markers, Chest Pain, Troponin I, Cardiovascular Diseases, Emergency Service, Hospital, Troponin


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