Biomarker Release After Percutaneous Coronary Intervention

Abstract

Cardiac biomarkers of necrosis provide clinicians with important “messages” from the heart. They are released into the interstitium of the myocardium after loss of the integrity of cardiac myocyte membranes. The pattern of the rise and fall of an individual biomarker (ie, its release kinetics) depends on its intracellular location in the myocyte, molecular weight, and clearance from the interstitium of the myocardium and ultimately the circulation.1 Cardiac biomarkers play an integral role in the clinical diagnosis of myocardial infarction (MI). Referring to the spontaneous occurrence of MI in patients, the World Health Organization required that at least 2 of the following be present to fulfill the criteria for MI: a history of ischemia-type chest discomfort, evolutionary changes on serially obtained ECG tracings, and a rise and fall in serum cardiac markers.2 Article see p 10 See Editorial Circulation . 2008;118:609–611 See Article Circulation . 2008;118:632–638 Several dramatic advances have occurred in the biomarker component of the diagnosis of MI. Analytes with greater specificity for the myocardium were introduced into clinical medicine, with creatine kinase-MB replacing total creatine kinase and subsequently cardiac-specific troponins replacing creatine kinase-MB as the biomarker of choice for diagnosing MI.3 Assay technology improved as clinical chemists moved from enzymatic activity assays for CK to highly specific immunoassays that can detect progressively smaller concentrations of cardiac troponins in the peripheral circulation.4 Although ST-elevation MI (STEMI) is easily identified on the 12-lead ECG, we now recognize that many patients previously diagnosed with unstable angina are more properly diagnosed as having non–ST-elevation MI (NSTEMI) on the basis of the detection of elevated levels of cardiac troponins in their blood.5 Cardiac biomarkers are used as a rough guide to the extent of myocardial necrosis. The higher the peak biomarker level after STEMI, the larger the …