Myocardial contrast echocardiography in acute myocardial infarction

Abstract

During acute myocardial infarction (AMI), the immediate therapeutic goal is to establish patency of the infarct-related artery. The restoration of epicardial coronary artery patency, however, is not equivalent to restoration of nutritive tissue flow. Functional and structural microvascular disruption (no-reflow phenomenon), despite infarct artery patency, is an important pathophysiologic phenomenon in the setting of reperfused AMI. Because the extent of no-reflow parallels the extent of necrosis, its identification is valuable in predicting the degree of myocardial salvage after treatment for AMI. Myocardial contrast echocardiography (MCE) principally interrogates the intramyocardial microvasculature and is thus ideally suited for assessing microvascular reflow after acute infarct reperfusion. MCE reperfusion patterns are predictive of the extent of recovery of ventricular function, complications after AMI, ventricular remodeling, and coronary flow reserve impairments. Furthermore, MCE during acute coronary occlusion delineates the area at risk for necrosis and extent of collateral blood flow. MCE thus has multiple clinically useful applications in the setting of AMI.