Critical review and meta-analysis on the combination of heart-type fatty acid binding protein (H-FABP) and troponin for early diagnosis of acute myocardial infarction.

An early diagnosis is crucial for effective triage and management of patients with suspected acute myocardial infarction (AMI). Although troponin testing is the cornerstone of diagnosis, the sensitivity of this biomarker is still suboptimal at patient admission. The heart-type fatty acid binding protein (H-FABP) is an early and sensitive biomarker of myocardial ischemia, whose appropriate setting is in combination with troponin testing. We performed a systematic review and meta-analysis of articles that have assessed the combination of troponin and H-FABP in the early diagnosis of AMI. Eight studies, totaling 2735 patients, met the inclusion criteria but none of them used a high-sensitivity troponin immunoassay. The between-study variation was high (98.5%), and attributable to heterogeneity. When considered alone, troponin exhibited a significantly greater pooled area under the curve (AUC) than H-FABP alone (0.820 versus 0.784; p<0.001). The pooled specificity was also higher for troponin alone than for H-FABP alone (0.94 versus 0.83; p<0.001), whereas the cumulative sensitivity was lower for troponin than for H-FABP (0.73 versus 0.80; p=0.02). The combination of both biomarkers exhibited a greater AUC than troponin alone (0.881; p<0.001), as well as a higher pooled sensitivity (0.91; p<0.001), which was however counterbalanced by a lower specificity (0.82; p<0.001). These results attest that the combination of H-FABP with a conventional troponin immunoassay seems advantageous for increasing the sensitivity of the former biomarker, at the expense of a lower specificity. The introduction of H-FABP testing would hence require careful assessment of laboratory data or clinical signs and symptoms for excluding sources of elevation different from AMI. Further studies are needed to assess the diagnostic effectiveness of combining H-FABP with a high-sensitivity troponin immunoassay.