Heart-type fatty acid-binding protein predicts long-term mortality after acute coronary syndrome and identifies high-risk patients across the range of troponin values

Objectives Our aim was to determine if a high-performance assay for heart-type fatty acid-binding protein (H-FABP) has a role in predicting all-cause mortality after acute coronary syndrome (ACS). Background Heart-type fatty acid-binding protein is released into the circulation following myocardial ischemia and necrosis and therefore may be of value to physicians when caring for patients admitted to hospital with a clinical diagnosis of ACS. Methods This was a prospective observational study with a follow-up of 12 months. The H-FABP was measured 12 to 24 h after onset of symptoms in 1,448 patients admitted to hospital with ACS, The main outcome measure was all-cause mortality 1 year after index hospital admission. Multivariable analyses were conducted using the well validated GRACE (Global Registry of Acute Coronary Events) variables together with troponin I and highly sensitive C-reactive protein (hs-CRP). Results After 12 months of follow-up, 296 patients had died. Multivariable analysis demonstrated that H-FABP quartiles were strongly predictive of outcome: Q1 hazard ratio (HR) 1.0; Q2 HR 2.32 (95% confidence interval [Cl] 1.25 to 4.30; p = 0.007); Q3 HR 3.17 (95% Cl 1.73 to 5.82; p < 0.001); Q4 HR 4.88 (95% Cl 2.67 to 8.93; p < 0.001). The crude all-cause 1-year mortality for unstable angina patients with H-FABP <5.8 mu g/l was 2.1% compared with 22.9% for patients above this cutoff. The adjusted all-cause mortality HR in this group was 11.35 (95% Cl 2.00 to 64.34; p = 0.006). Conclusions Heart-type fatty acid-binding protein predicts long-term mortality after ACS and identifies high-risk patients in a manner that is additive to the GRACE clinical risk factors, troponin, and hs-CRP, possibly as a result of identifying the occurrence of myocardial ischemia with or without necrosis.