Contrast echocardiography accurately predicts myocardial perfusion before angiography during acute myocardial infarction

Abstract

O ptimal therapy during acute myocardial infarction (AMI) includes prompt re-establishment of flow in the infarct-related artery (IRA) and effective reperfusion (1-3). Early, spontaneous reperfusion occurs in a small but significant proportion of IRAs (4,5), and the majority are reperfused with thrombolytic therapy. It is difficult to determine whether patency has been achieved at a given time in most patients without cardiac catheterization. The availability of a noninvasive method to rapidly assess myocardial perfusion has important implications in the emergency management of patients presenting with a known or suspected AMI, or after administration of a thrombolytic agent. However, no technique has yet been demonstrated to quickly and reliably predict the effectiveness of reperfusion or status of the IRA.Myocardial contrast echocardiography (MCE) uses an injection of microbubbles to assess myocardial perfusion. MCE can be used to reliably assess myocardial reperfusion following primary percutaneous coronary intervention (PCI) for AMI and to predict improvement in left ventricular (LV) function, as well as to assess the degree of collateral support to the infarcted territory (6-17). However, due to time constraints and the technical demands of OBJECTIVES: To determine whether myocardial contrast echocardiography (MCE) can quickly and accurately assess myocardial perfusion and infarct-related artery (IRA) patency before emergency angiography during acute myocardial infarction (AMI). BACKGROUND: Despite encouraging experimental and clinical studies, the reliability and practicality of MCE in predicting IRA patency during AMI before angiography has not been proven. METHODS: Two-dimensional echocardiography and MCE were performed in 51 patients with AMI just before emergency angiography. With knowledge of the electrocardiogram findings and regional wall motion, myocardial perfusion was assessed to predict IRA patency. RESULTS: Myocardial perfusion studies were adequate for interpretation in 40 patients. An occluded IRA was predicted in 28 patients; the artery was occluded in 22 patients, and six patients had Thrombolysis In Myocardial Infarction (TIMI) grade 2 flow or less. A patent IRA was predicted in 12 patients; eight patients had TIMI grade 3 flow, one patient had TIMI grade 2 flow and the IRA was occluded in three patients. In one of the three patients, the appropriate view was not obtained. In another patient, collateral flow was adequate for nearnormal regional wall motion, and in the last, the findings suggested reperfusion of the proximal artery with distal embolic occlusion. Taken together, MCE accurately predicted either TIMI grade 2 flow or less, or TIMI grade 3 flow in 36 of 40 patients. Sensitivity was 87.5%, specificity and positive predictive value were 100% and negative predictive power was 66.7% (P<0.001). CONCLUSIONS: MCE, together with the electrocardiogram and regional wall motion, can be used to quickly and reliably predict IRA patency early during AMI and may be useful to facilitate a manag...

A canine acute coronary occlusion model using thrombus implantation by percutaneous coronary intervention

“…For each parameter in each region, the mean value of three measurements was then calculated. Plots of contrast intensity versus time were constructed and fitted to an exponential function, y = A (1 − e − βt) [20]. The plateau of signal intensity (A) and the slope of maximum signal intensity rise (β) were measured, and the product of A × β was computed.…”

Advanced Echocardiography Techniques: The Future Stethoscope of Systemic Diseases

“…The degree of IRA's patency influences the decision-making process when planning for percutaneous intervention (PCI) as a life-saving procedure in acute myocardial infarction. 136 MCE showed superiority over thrombolysis in myocardial infarction (TIMI) score, providing accurate prognostic information regarding the risk of short- and long-term cardiac events. 137 Furthermore, intriguing preclinical conclusions that high-mechanical-index flashes during UEA infusion can restore defective microvasculature have motivated the clinical trial of MCE as a supportive therapeutic measure (so-called sonothrombolysis) in ST-elevated myocardial infarction.…”

Accuracy of Resolution of ST-Segment Elevation in Electrocardiogram to Determine the Patency of Infarct-Related Artery

“…Angiography is a gold standard technique to measure the patency of infarct-related artery (IRA) [ 6 ]. Non-invasive techniques such as an ECG can also be used to predict the reperfusion status [ 7 ]. Ahmed et al indicated in their pilot study that a 50% reduction in the sum of ST-segment elevations at four hours after intravenous streptokinase was a useful indicator of the outcome of reperfusion [ 8 ].…”