Common use of Infarction types and pathogenesis Clause in Contracts

Infarction types and pathogenesis. Critical myocardial ischemia may arise as a result of increased myocardial metabolic requirement and/or reduction in the delivery of oxygen and nutrients to the myocardium through the coronary circulation, or both. An interruption in the supply of myocardial oxygen and nutrients occurs when blood flow to the myocardium is interrupted by occlusion of a coronary artery. Often, this event is caused by a thrombus superimposed on an ulcerated or unstable atherosclerotic plaque that left untreated for as little as a 20-40 minutes, can lead to irreversible cell damage and cell death. A high-grade (> 75%) permanent coronary artery stenosis due to atherosclerosis or a dynamic stenosis coupled with coronary vasospasm can also reduce the supply of oxygen and nutrients and be a factor involved in AMI. Additional cardiac valvular pathologies and low cardiac output states associated with a decreased aortic diastolic pressure, which is the prime component of coronary perfusion pressure, can also precipitate AMI.