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
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 [CI] 1.25 to 4.30; p = 0.007); Q3 HR 3.17 (95% CI 1.73 to 5.82; p < 0.001); Q4 HR 4.88 (95% CI 2.67 to 8.93; p < 0.001). The crude all-cause 1-year mortality for unstable angina patients with H-FABP <5.8 μg/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% CI 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.
Abbreviations and Acronyms
ACS
acute coronary syndrome
CV
coefficient of variation
ECG
electrocardiogram
H-FABP
heart-type fatty acid-binding protein
hs-CRP
highly sensitive C-reactive protein
MI
myocardial infarction
TnI
troponin I
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The structure of the EMMACE-2 Study Group is provided as an Online Appendix.
Prof. Hall and Dr. Barth have received support in the form of free reagents from Beckman Coulter and Dainippon Pharmaceutical and research grants from AstraZeneca and Sanofi-Aventis in support of the EMMACE-2 study.