From the Guidelines
Acute ST elevation is primarily caused by an occlusion of a major coronary artery due to physical disruption of an atherosclerotic plaque with subsequent formation of an occluding thrombus, as stated in the European Heart Journal study 1. The pathogenesis of ST-segment elevation acute myocardial infarction involves the disruption of an atherosclerotic plaque, which can be caused by various factors such as plaque composition and vulnerability, degree of stenosis, and inflammation. Some key points to consider are:
- The risk of plaque disruption depends on plaque composition and vulnerability (plaque type) and degree of stenosis (plaque size) 1.
- Inflammation plays an important role in plaque instability, and therefore in the pathogenesis of acute coronary syndromes, with circulating levels of inflammatory markers such as C-reactive protein (CRP) and interleukin-6 correlating with the clinical course and outcome of an acute coronary syndrome 1.
- The circadian variation of STEMI, with a higher incidence in the early morning hours, can be explained by the combination of β-adrenergic stimulation, hypercoagulability of the blood, and hyper-reactivity of platelets 1.
- Myocardial necrosis caused by complete coronary artery occlusion begins to develop after 15–30 min of severe ischaemia and progresses from the subendocardium to the subepicardium in a time-dependent fashion 1. The thrombotic response to plaque disruption is dynamic, involving thrombosis and clot lysis, often associated with vasospasm, which can cause intermittent flow obstruction and distal embolization 1. Therefore, the primary cause of acute ST elevation is the occlusion of a major coronary artery, which can be triggered by various factors, including plaque disruption, inflammation, and circadian variation, as supported by the study published in the European Heart Journal 1.
From the Research
Causes of Acute AST Elevation
- Acute myocardial infarction (AMI) can cause AST elevation, as AST is present in cardiac muscle 2, 3, 4.
- Liver disorders, such as ischemic hepatitis, acute viral hepatitis, and drug-induced liver injury, can also cause AST elevation 5.
- The transaminase ratio (AST/ALT) can be used to screen for liver diseases and has been found to be higher in patients with ST-segment elevation myocardial infarction (STEMI) than in non-ST-segment elevation myocardial infarction (NSTEMI) patients 4.
- Heart or circulatory system failure can lead to acute and chronic liver diseases, including ischemic hepatitis, congestive hepatopathy, cardiac cirrhosis, and Fontan liver disease 6.
- The AST/ALT ratio has been found to be associated with total coronary occlusion, and a ratio of ≥ 2.0 may be used to predict coronary occlusion 4.