Diagnostic and prognostic value of heart-type fatty acid-binding protein in the early hours of acute myocardial infarction

BACKGROUND: Heart-type fatty acid-binding protein (H-FABP) is a cytosolic protein that is released into the bloodstream when the myocardium is injured. The aim was to determine the diagnostic and prognostic value of H-FABP in patients with suspected acute myocardial infarction (AMI) within the first 3-6 hours after the onset of chest pain. METHODS AND RESULTS: A consecutive series of 165 patients with chest pain lasting less than 6 hours were enrolled in a forward observational design in the emergency department.The diagnostic validity of H-FABP was evaluated according to sensitivity, specificity, and predictive values, likelihood ratios, ROC curves, and multivariate logistic regression analyses. The prognostic value of H-FABP at 6 months was checked using survival curves and the multivariate Cox proportional hazards model. The sensitivity of H-FABP was 81% (95% CI: 69.2-92.9). Its area under the ROC curve: 0.729 (95% CI: 0.63-0.83) and negative likelihood ratio (0.38; 95% CI: 0.22-0.65) were significantly better than both troponin (cTnI) and CK-MB, whereas its specificity, 53% (95% CI: 41.1-64.8), was lower than that of the other markers. Increased H-FABP added diagnostic information as it demonstrated independent association with AMI by logistic regression analysis. Increased H-FABP and cTnI were both strong and independent predictors of outcome in the 6-month follow-up (hazard ratio: 2.18; 95% CI: 1.07-4.42; and 2.34; 95% CI: 0.98-5.59, respectively). CONCLUSIONS: H-FABP is, within 6 hours and also within 3 hours, more sensitive than the other markers in the early diagnosis of AMI and it is an independent prediction factor of events within 6 months.