Serial measurement of heart-type fatty acid binding protein for the rapid diagnosis of acute coronary syndromes in the emergency department

Introduction: We aimed to investigate the diagnostic accuracy of heart-type fatty acid binding protein (H-FABP) at admission and the third and sixth hour after admission in patients presenting to the emergency department (ED) with chest pain or equivalent symptoms. Methods: This prospective study was performed over two months in the ED. Patients presenting with ischaemic-type chest pain or other symptoms suggestive of myocardial ischaemia were included in the study. A bedside, point-of-care, quantitative H-FABP level was measured. If the initial electrocardiography (ECG) was non-diagnostic, the patients were observed for six hours. During the observation period, serial H-FABP measurements were obtained at admission, the third hour and the sixth hour; serial measurements of total creatine kinase (CK), CK-MB, troponin I and myoglobin were recorded at admission and the sixth hour. Results: A total of 183 patients were included in the study. Initial H-FABP was measured in a joint group of ST segment elevation myocardial infarction (STEMI) and non ST segment elevation myocardial infarction (NSTEMI) patients, with a sensitivity of 80.9%, specificity of 19.2%, positive predictive value (PPV) of 23% and negative predictive value (NPV) of 77.1%. The third-hour H-FABP was measured in the NSTEMI group, with a sensitivity of 46.7%, specificity of 80.2%, PPV of 42.4% and NPV of 82.6%. The sixth-hour H-FABP had a sensitivity of 33.3%, specificity of 73.9%, PPV of 24.2% and NPV of 81.5%. Conclusion: H-FABP is superior to myoglobin for diagnosing myocardial infarction in a joint group of STEMI and NSTEMI patients. The third-hour NPV value for H-FABP indicates that, for safety considerations, the cardiac observation time should not be shortened.