Pathophysiology and Definition of the Acute Coronary Syndromes

Abstract

Patients presenting with acute coronary syndromes (ACS) include a wide spectrum of conditions, and it is worthwhile to appreciate the range of this disease process. ACS in general comprise a range of acute myocardial ischemia and include a continuum of acute myocardial ischemia manifested by STEMI, NSETMI, and UA.

Awareness of the pathophysiology and definitions of ACS is especially important since diagnosis of myocardial injury has become more prevalent with the recent advent of high-sensitivity troponins. Appreciation of the pathophysiology of ACS has offered an approach for recent therapy corresponding to these conditions. This understanding has also led to several investigational methods. The clinical classification of ACS which is traditionally based on electrocardiographic and cardiac injury marker information is important in the acute diagnosis and treatment of ACS. The main issue is rupture of a vulnerable coronary atherosclerotic plaque which is contributed by inflammatory and other detrimental developments. This can lead to plaque rupture contributing to thrombotic coronary occlusion. Essentially this can conclude in an acute coronary syndrome. Equally important is the appreciation of the condition of myocardial infarction with nonobstructive coronary syndrome (MINOCA) which is a condition that is defined as evidence of MI with near normal coronary arteries. It is important to further understand that specifics of ACS are factored by anatomic, hemodynamic, and degree of coronary obstruction as ACS is viewed as a continuum of increasing severity and acuity.

Update of original chapter by Ezra Amsterdam and Doug Kirk.