Diagnostic and prognostic performance of heart-type fatty acid-binding protein in functionally relevant coronary artery disease.

BACKGROUND: This study aimed to evaluate the diagnostic and prognostic utility of heart-type fatty acid-binding protein (H-FABP) in patients with suspected functionally relevant coronary artery disease (fCAD). METHODS: The presence of fCAD was centrally adjudicated using myocardial perfusion imaging and coronary angiography. H-FABP high-sensitivity cardiac troponin T (hs-cTnT), and high-sensitivity cardiac troponin I (hs-cTnI) concentrations were measured at rest, peak stress, and 2 h after stress in a blinded fashion.Centrally adjudicated outcomes included all-cause death and cardiovascular death during 8-years. RESULTS: Among 2690 patients included in the diagnostic analysis (median age 68 years, 32% women), fCAD was present in 924 individuals (34%). Baseline H-FABP concentrations were higher in patients with fCAD than in those without (29 [23-38] vs 27 [22-35] ng/mL, p < 0.001), but diagnostic discrimination was low (AUC 0.561, 95%CI: 0.538-0.584). H-FABP measured at peak stress (AUC 0.566) and 2 h post-stress (AUC 0.569) also showed only low discrimination. Addition of H-FABP to clinical assessment resulted in only a marginal but statistically significant improvement (AUC 0.634 [95%CI 0.612-0.656] versus 0.626 [95% CI 0.604-0.648], p = 0.018). Among 2645 patients available for the prognostic analysis, H-FABP showed a strong graded association with all-cause death and cardiovascular death. Eight-year all-cause mortality increased from 7.7% in the lowest quartile to 44% in the highest quartile (p < 0.001). Prognostic discrimination was moderate-to-high (c-index 0.71), comparable to hs-cTnT and hs-cTnI, and provided incremental prognostic information beyond a comprehensive clinical model. CONCLUSIONS: H-FABP demonstrated limited diagnostic accuracy for detecting fCAD but is strongly and independently associated with long-term mortality.