Introduction We have previously shown that heart-type fatty acid binding protein (H-FABP) has a role in predicting all-cause mortality after acute coronary syndromes (ACS) and after multivariable analysis, provides additional information to that gained from the GRACE clinical risk factor score, troponin and highly sensitive CRP. H-FABP is released into the circulation during myocardial ischaemia and after myocardial necrosis, in contrast to troponin which is released after myocardial necrosis only. We have also shown that there is a group of ACS patients who are at high risk of cardiac events and death despite normal troponin levels on admission. This group may benefit from an early invasive strategy.
Hypothesis Plasma H-FABP level, taken between 12 and 24 h after admission, can identify troponin negative ACS patients who are at a high long term risk of death.
Methods Six-year mortality data is now available for patients enrolled in the FAB 1 study, for which 1-year mortality data was published in 2007. In this study, 1448 unselected patients admitted to hospital with ACS had serum H-FABP level measured in addition to usual care. Mortality was tracked by the UK Office of National Statistics.
Results At 6 years overall all-cause mortality, available for 1421 patients (98.1%), was 43.5%. If troponin −ve/H-FABP −ve mortality was 20.9%; troponin −ve/H-FABP +ve 56.4%; troponin +ve/H-FABP −ve 20.2%; troponin +ve/H-FABP +ve 49.1%. Mortality rate was independent of troponin status but strongly related to H-FABP status.
Conclusion The current system of stratification of ACS patients for early invasive management if troponin positive will miss a cohort of patients who are at high risk of death despite being troponin negative, and who may benefit from invasive investigation. Conversely, it is likely that some ACS patients undergo angiography based on a false positive troponin level. The addition of H-FABP measurement to the management of ACS could avoid this.