[Biochemical markers in the diagnosis of acute coronary syndrome]

Acute coronary syndrome is a set of symptoms interpreted as being the result of cardiac ischemia. The subtypes of acute coronary syndrome, depending on the degree of cardiac ischemia, include unstable angina and two forms of myocardial infarction. Determination of serum cardiac markers plays a key role in the diagnosis of acute myocardial infarction. Serum markers such as aspartate transaminase, lactate dehydrogenase, and creatine kinase are no longer used because they lack cardiac specificity and sensitivity. According to the NACB (National Academy of Clinical Biochemistry) recommendations, two serum cardiac markers need to be determined for routine diagnosis of acute myocardial infarction, i.e. one showing early elevation in serum (up to six hours after chest pain), and the other, late marker that is elevated six to nine hours after chest pain, has high sensitivity and specificity for detection of myocardial injury, and remains elevated for several days of the symptom onset. In current clinical practice, myoglobin, CKMB mass (improved diagnostic sensitivity in relation to CKMB activity) and cardiac troponins are commonly determined. CKMB mass is a cardiospecific marker, but can also be elevated in skeletal muscle damage. Myoglobin is not cardiospecific, but has high early sensitivity (fast and reliable exclusion of acute myocardial infarction) and the possibility of rapid assessment of the success of thrombolytic therapy. Cardiac troponins are late markers for the diagnosis of myocardial injury. They are markers with highest specificity and sensitivity for acute myocardial infarction. New markers such as ischemia modified albumin, heart fatty acid binding protein, glycogen phosphorylase isoenzyme BB, carboanhydrase 3, and new tehnologies are under investigation to advance our knowledge about heart disease.