Cardiac markers for assessing the acute coronary syndromes. A focus on cardiac troponins.

Markers of myocardial injury will continue to play an essential role in the assessment and management of patients presenting within the spectrum of acute coronary syndromes, a term representing the continuum of acute myocardial ischemia ranging from angina through Q-wave myocardial infarction. Coronary artery lesion instability can be detected by markers of plaque inflammation and disruption, platelets reactivity, and thrombosis. When myocardial injury occurs with severe impairment of coronary blood flow, several markers are released from the damaged myocyte. For many years, creatine kinase-MB isoenzyme has been the conventional marker for myocardial infarction. Despite its inadequate sensitivity and specificity for myocardial injury, creatine kinase-MB remains an essential component in assessing re-infarction or infarct extension, as well as in monitoring reperfusion after thrombolytic therapy when combined with myoglobin. Among the many cardiac markers for myocardial necrosis, cardiac troponins possess superior sensitivity and specificity for the detection of myocardial injury. In addition to their superior performance in detecting minor myocardial damage, cardiac troponins can be useful in detecting perioperative myocardial infarction, infarct size, improving risk stratification, and facilitating therapeutic decision making in patients with acute coronary syndromes.