Unstable angina: Comparison of prognostic values of cardiac fatty acid binding protein and troponin I.

Cardiac fatty acid binding protein (FABP) was proposed as an early marker o f myocardial damage. The aim of this study was to compare prognostic value of FABP with that of such established predictor as cardiac troponin I (Tnl) in patients with acute coronary syndrome without ST segment elevation. Ser um FABP and Tnl levels were measured (HyTest, Finland) in 59 patients (50 w ith unstable angina, 9 with non-Q-myocardial infarction) admitted within 24 hours (median 5,3) after onset of pain at admission and in 24 h tin all) a nd in 6, 12 h (in some patients) from index attack of angina. Ischemic even ts (Q wave infarction or chest pain at rest lasting more than 10 min) were registered during period of hospitalization (17,4+/-7,1 days). Ischemic eve nts occurred in 20 patients (myocardial infarction in 2 and attacks of angi na at rest in 18). Median FABP levels were 26,4 and 7,2 (p<0,001) at admiss ion, 5,8 and 31,4 ng/ml (p=0,007) in 6 h after onset of pain in patients wi th and without events, respectively. There were no significant differences between patients with and without ischemic events in Tnl I levels. Overall elevated FABP (>6 ng/ml) was found in 42 (71%) while elevated Tnl level (>0 ,4 ng/ml) - in 16 patients (27%). At admission FABP level exceeded 6 ng/ml in 19 (95%) and 23 (59%) (p=0,009), in 6 hours after onset of pain - in 12 (100%) and 11 (50%) (p=0,009) patients with and without ischemic events res pectively. Proportions of patients with elevated Tnl level was similar amon g patients with and without ischemic events. At multivariate logistic regre ssion analysis age (p=0,003), history of myocardial infarction (p=0,04) and FABP level at admission (p=0,02) were independently associated with ischem ic events during hospitalization. Sensitivity, specificity, positive and ne gative predictive power for FABP at admission were 95%, 41%, 45% and 94%, r espectively. Thus in a group of patients with unstable coronary artery dise ase with relatively short interval from index angina attack to blood sampli ng level of FABP was often elevated and this level turned out to be better related to in-hospital ischemic events than the level of troponin I.