教育演講4:急性冠心症治療的新趨勢
Current Management of Acute Coronary Syndrome

E4-1
Acute Coronary Syndrome: Overview
Juey-Jen Hwang, MD, PhD
Professor of Medicine, National Taiwan University College of Medicine; Director of Medical & Coronary Intensive Care Units, National Taiwan University Hospital, Taipei, Taiwan

  Acute coronary syndrome (ACS) is a major cause of morbidity and mortality worldwide. More than 3 million people each year are estimated to have an acute ST-elevation myocardial infarction, with more than 4 million having a non-ST-elevation myocardial infarction. From being an illness seen predominantly in developed countries, ACS is now becoming increasingly more common in developing countries.

  Disruption of plaques is now considered to underline most cases of ACS. When plaque disruption occurs, a sufficient quantity of thrombogenic substances is exposed, and the coronary artery lumen may become obstructed by a combination of platelet aggregates, fibrin and red blood cells that may produce an extensive thrombus filling a large segment of the infarct-related artery. This thrombotic process diminishes microcirculatory perfusion by reduced coronary artery flow through epicardial stenoses, as well as by distal embolization of thrombus. This pathophysiology provides the rationale for fibrinolytic and anti-thrombotic therapies, whereas residual epicardial stenoses are targets for percutaneous and surgical revascularization approaches.

  Vulnerable plaques likely to rupture or erode have evidence of inflammation with monocytes, macrophages, and T-cell infiltrates, together with thin fibrous caps and large lipid cores. Platelet hyper-reactivity and procoagulant states also contribute to this thrombotic disease. Additionally, coronary spasm, emboli, or dissection of the coronary artery are causes of infarction in the absence of occlusive atherosclerosis, and are reported in 5–10% of patients with ST-elevation myocardial infarction and 10–15% of patients with non-ST-elevation myocardial infarction.

  The contribution of lifestyle factors in the development of ACS was also emphasized in recent studies. Ninety percent of myocardial infarction were attributable to modifiable risk factors such as smoking, dyslipidemia, hypertension, abdominal obesity, and diabetes in men (94% in women). Rapid diagnosis and management will be discussed in this symposium.