Heart type fatty acid binding protein (H-FABP) – a marker of myocardial ischemia?

Heart type fatty acid binding protein (H-FABP) is a cytoplasmic protein involved in the uptake and buffering of free fatty acids in the myocardium. This novel marker has been shown to predict long term mortality in acute coronary syndromes independent of clinical risk factors, troponin and high sensitivity C-reactive protein. While troponin is a marker of myocardial necrosis, H-FABP seems to be a marker for myocardial ischemia, even without necrosis.
A recent study published in J Am Coll Cardiol, 2010; 55:2590-2598, by Karthik Viswanathan et al found that H-FABP predicts long term mortality and re-infarction in patients with suspected acute coronary syndrome, but are troponin negative. Thus estimation of H-FABP is useful in low and intermediate risk suspected acute coronary syndrome patients. H-FABP is useful as a marker of myocardial ischemia even in the absence of frank myocardial necrosis. In those who were troponin negative, a cut off value above 6.48 microgram/litre identified patients at very high risk for death or readmission with myocardial infarction within a follow up period of one year. This predictive value was independent of age and serum creatinine values. Authors recommend further investigations like coronary angiography in this subgroup of patients. The current study had evaluated a large unselected cohort of about thousand patients. Those ST elevation myocardial infarction and new onset left bundle branch block were excluded from the study. Other studies have noted that H-FABP has a prognostic value independent of N-terminal pro–B-type natriuretic peptide and troponin.