Direct comparison of the diagnostic value of point-of-care tests detecting heart-type fatty acid binding protein or glycogen phosphorylase isoenzyme BB in patients with acute coronary syndromes with persistent ST-segment elevation.

BACKGROUND Myocardial infarction (MI) with its complications is one of the most serious challenges in contemporary cardiology. Among biochemical markers of myocardial necrosis, heart-type specific fatty acid binding protein (h-FABP) showed excellent sensitivity and specificity for the early diagnosis of an acute MI. The h-FABP is released rapidly (after 30 min) from the cardiomiocyte to the circulation in response to myocardial injury and may be useful for rapid confirmation or exclusion of MI. In recent years, glycogen phosphorylase BB (GP-BB) also emerged as a promising early specific marker of myocardial necrosis. Rapid, qualitative "point of care" tests (POCT) detecting h-FABP (Cardio Detect med) and GP-BB (Diacordon) have recently become available. AIM To evaluate and compare qualitative POCTs detecting h-FABP and GP-BB in patients with an acute coronary syndrome (ACS). METHODS We studied 52 patients with a strong suspicion of ACS with persistent ST-segment elevation and chest pain lasting less than 6 hours. The ultimate diagnosis of ST-segment elevation MI (STEMI) was confirmed in case of a second (6 h after admission) positive quantitative result of a cardiac troponin T (cTnT) test. On admission, POCTs to detect both h-FABP and GP-BB were performed. The study population was divided into two groups, with chest pain lasting 〈 3 h (n = 20) or 4-6 h (n = 32). All patients underwent coronary angiography and angioplasty if indicated. The sensitivity of the analysed biomarkers of myocardial necrosis was calculated. RESULTS The sensitivity of h-FABP (84%) was superior in comparison to the other biomarkers, GP-BB and cTnT, which had sensitivity of 64% and 50%, respectively. Comparison of typical parameters of the diagnostic value of a test (sensitivity, predictive values and accuracy) in both time periods demonstrated that h-FABP was superior to GP-BB. In particular, sensitivity and accuracy of h-FABP was excellent in the group of patients with chest pain lasting 〈 3 h, with sensitivity of 79% for h-FABP and only 47% for GP-BB. Sensitivity and accuracy of cTnT were significantly lower (32% and 35%, respectively). CONCLUSIONS The h-FABP seems to be an excellent early biomarker of cardiac necrosis in the group of patients with chest pain lasting 〈 3 h. The GP-BB can be also used as a biomarker of myocardic necrosis, but its sensitivity in the early phase of MI is limited.