Heart-type fatty acid binding protein and the diagnosis of acute coronary syndrome in the ED

Abstract

BackgroundIn combination with cardiac troponin, heart-type fatty acid binding protein (h-FABP)—a biomarker of myocardial necrosis—offers the possibility of rapidly eliminating the diagnosis of acute myocardial infarction (AMI). ObjectiveThe main objective of this study was to assess the incremental value of h-FABP to cardiac troponin for a rapid elimination of AMI, according to the pretest probability (PTP) of AMI. MethodsIn consecutive patients presenting to emergency departments (ED) with chest pain less than 6 hours suggestive of AMI, h-FABP levels were measured, blinded to the ED physicians, who were asked to quote the PTP of AMI. The discharge diagnosis was adjudicated by 2 independent experts, blind to the h-FABP level. ResultsThree hundred seventeen patients (mean age of 57 years) were included in whom 149 had (47%) low, 117 (37%) moderate, and 51 (16%) high PTP. The final diagnosis was AMI in 45 patients (14%), including 16 STEMIs (5%). The negative predictive value for diagnostic elimination of AMI of an h-FABP less than 3 μg/L, combined with a negative cTnI was not higher than that of cardiac troponin I (cTnI) alone (96% [95% confidence interval, 93%-98%] vs 95% [93%-98%]), regardless of the PTP). Even in the low-PTP group, we did not demonstrate a significant improvement in negative predictive value with the addition of h-FABP, compare with that of cTnI alone (100% [97%-100%] vs 99% [96%-100%]). ConclusionIn triage of patients with chest pain, use of h-FABP does not provide useful additional information to cTnI for excluding the diagnosis of ST-elevation myocardial infarction and non–ST-elevation myocardial infarction diagnosis, whatever the PTP.