Evaluation of the diagnostic performance of heart-type fatty acid binding protein in the BWH-TIMI ED chest pain study

Chest pain is one of the most common reasons for presentation to the Emergency Department and the ability to rapidly and correctly diagnose the minority of patients who have a myocardial infarction is of critical importance. We assessed the diagnostic performance of a multimarker strategy using heart-type fatty acid binding protein (H-FABP) in combination with a contemporary sensitive troponin (cTn) assay. We measured H-FABP (Randox) and a sensitive cTn (TnI-Ultra, Siemens) at baseline in 343 patients with chest pain enrolled in the prospective BWH-TIMI ED chest pain study. Final presenting diagnosis was adjudicated using all diagnostic data, including the local cTnI results, but reviewers were blinded to H-FABP and the sensitive cTn assays. The diagnostic accuracy of H-FABP and local cTn together (AUC 0.962) was superior to local cTn alone (AUC 0.910, p = 0.0009) with an especially marked improvement in early presenters (AUC 0.983 vs. 0.840, p = 0.0098). In contrast, when combined with the sensitive cTn assay, there was no significant difference in the AUC with H-FABP as compared with the sensitive cTn alone, either in the overall cohort (AUC 0.963 vs. 0.956, p = 0.23) or in early presenters (AUC 0.999 for both). In early presenters, the addition of H-FABP resulted in a NPV of 100 % when combined with either the local or sensitive cTn assay. In our study, the addition of H-FABP significantly enhanced the sensitivity and accuracy of diagnosis as compared to a prior-generation troponin assay alone, especially in patients who presented early. H-FABP but did improve overall diagnostic accuracy when added to a current-generation sensitive troponin assay; however, their combination offered the best NPV in early presenters. Further studies are needed to determine the utility a very rapid “rule out” of MI with a single blood draw of troponin and H-FABP at presentation.