Acute Coronary Syndrome: Guidelines and Definitions

Coronary artery disease (CAD) is a major cause of death worldwide. Clinical presentations of CAD include silent ischemia, stable angina pectoris, unstable angina (UA), myocardial infarction (MI), heart failure, and sudden death. It is well established that acute coronary syndromes (ACS) in their various settings share a widely common pathophysiological substrate. ACS represent a life-threatening manifestation of atherosclerosis. In rare cases, ACS may have a nonatherosclerotic etiology such as arteritis, trauma, dissection, thromboembolism, congenital anomalies, cocaine abuse, or complications of cardiac catheterization. The most urgent priority of early evaluation is to identify patients with ST-segment elevation myocardial infarction (STEMI) who should be considered for immediate reperfusion therapy and to recognize other potentially catastrophic causes of patient symptoms, such as aortic dissection. Many randomized controlled trials (RCTs) and meta-analyses have assessed the effects of a routine invasive versus conservative or selective invasive approach in the short and long term.