Correlation of myocardial echo contrast disappearance rate (“Washout”) and severity of experimental coronary stenosis (original) (raw)
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American Heart Journal, 1994
Assessment of regional myocardial perfusion with myocardial contrast echocardiography in a canine model of varying degrees of coronary stenosis Previous studies showed that myocardial contrast echocardiography can be used to detect relative regional underperfusion in a canine model of critical coronary stenoses. The aim of this study was to determine if myocardial contrast echocardiography performed with a sterile sonicated human serum albumin preparation (Albunex, Molecular Biosystems, San Diego, Calif.) could detect the presence of coronary stenoses of variable degrees of severity. The results were compared with myocardial blood flow as assessed by radiolabeled microspheres in 16 open-chest dogs during baseline, following the creation of a coronary stenosis of variable severity and at the peak of dipyridamole-induced hyperemia. When flow ratios (that is, flow in the control arealischemic area) were examined, a good correlation was observed between the area under the time-intensity curve and radioactive microsphere blood flow (r = 0.94, p < O.OOOl), which allowed distinction of mild from severe stenosis. However, a consistent underestimation of the dipyridamole-induced hyperemia by myocardial contrast echo was seen in the control zone. This could be partially explained by a simultaneous increase in coronary blood flow and blood volume with dipyridamole and by attentuation of the ultrasound signal because of the high concentration of microbubbles at high flows. Myocardial contrast echocardiography can quantitate the amount of jeopardized myocardium during various degrees of coronary stenoses.
Circulation, 1984
A computer algorithm was developed and applied to measure brightness decay rates of myocardial contrast opacification observed with two-dimensional echocardiography (2DE). An agitated mixture of diatrizoate meglumine and saline (Renografin-saline) was injected into the left main coronary artery of 17 closed-chest dogs during the control state as well as after placement of an intracoronary plug to induce 85% stenosis in the left anterior descending coronary artery (LAD) in five dogs. In 12 dogs, injections were also performed distally to complete intracoronary balloon occlusion of the LAD. For each injection, up to 35 electrocardiographic-gated, end-diastolic 2DE frames were digitized into an image-processing computer that determined mean pixel brightness of each of 12 myocardial segments per 2DE short-axis cross-section. Time-activity curves for each segment were generated, and contrast decay half-life (t 1/2) was calculated. Mean t 1/2 for control-state injections was found to be 2...
Journal of the American Society of Echocardiography, 1995
A new intravenously administered ultrasound contrast agent was studied in eight dogs during intermittent coronary artery occlusion. The area of the myocardial contrast defect was compared with that of the acute wall motion abnormality induced by coronary occlusion. A close correlation was found between these two independent measures of acute myocardial ischemia. The peak change in myocardial intensity during coronary occlusion was significantly less than for the same segment before ischemia and for a remote nonischemic segment. This new, intravenously administered ultrasound contrast agent can be used to evaluate the spatial distribution of hypoperfused myocardium and should therefore prove valuable in the dinical evaluation of ischemic syndromes.
2016
Background. Myocardial opacification during echocardiography has been demonstrated after left (LA) and right (RA) atrial injections of contrast, and microvascular damage with reduced blood flow and impaired flow reserve has been documented in necrotic myocardial tissue. Therefore, we hypothesized that because of its ability to depict capillary perfusion, myocardial contrast echocardiography (MCE) can be used to define risk area during coronary occlusion and infarct size after reperfusion with LA and RA injections of contrast in the presence of pharmacologically induced coronary hyperemia. Methods and Results. Eighteen open-chest anesthetized dogs with 3 to 6 hours of left anterior descending artery occlusion and 15 minutes of reflow were studied in the presence of either dipyridamole (0.56 mg/kg over a period of 4 minutes) or dobutamine (15 tg. kg. * min'). Technetium autoradiography was performed for risk area assessment; infarct size was measured with triphenyl tetrazolium ch...
Reproducibility of quantitative myocardial contrast echocardiography
Journal of the American College of Cardiology, 1990
To determine whether myocardial contrast echocardiog raphy is quantitatively reproducible, repeated intracoronary injections of sonicated albumin (5%) were performed in eight open chest dogs. Paired injections were performed at baseline, during ischemia produced by ligation of a coronary artery, and during hyperemia induced by intravenous infusion of 0.75 mg/kg body weight of dipyridamole. Contrast washout curves were generated for the left anterior descending coronary artery territory (ischemic area) and left circumflex coronary artery territory (nonischemic area) by beat per beat analysis of frozen end-diastolic frames of left ventricular short-axis views. Peak contrast intensity, contrast washout half-time and area under the curve were derived from these curves. A total of 75 contrast washout curves were analyzed for the study of interhtjection, intraobserver and interobserver reproducibility.
American Heart Journal, 1996
The use ofintracoronary or intraaortic root injections of echo-contrast agents, myocardial contrast echocardiography (MCE), has proved useful in delineating individual coronary artery perfusion territories i and myocardial areas at risk 2"3 and in assessing coronary reserve, 4-i° results of percutaneous transluminal coronary angioplasty 6, 11-i2 and coronary artery bypass grafting, i3 presence and degree of coronary collaterals, i4~i5 and more recently the presence of myocardial viability in asynergic myocardium.15-i6 However, investigators have experienced variable degrees of success in obtaining sufficient transpulmonary passage ofechocardiographic contrast agents to achieve reproducible myocardial opacification.i7-25 This unpredictable transpulmonary passage has limited the use of MCE to the catheterization laboratory and has prevented the widespread application of the technique. Preliminary investigations by us and others would suggest that newer echocardiographic contrast agents might be able to achieve myocardial opacification after their intravenous injection. 26-3i On the basis of our preliminary observations 26-27 we hypothesized that FSO69, a new echocardiographic contrast agent that consists of a suspension of perfluoropropane-filled albumin mi-From the aSection
Detection of Coronary Stenoses at Rest With Myocardial Contrast Echocardiography
2010
Background-We hypothesized that autoregulatory changes in arteriolar blood volume (aBV) that develop distal to a stenosis can be measured with myocardial contrast echocardiography, allowing coronary stenosis detection at rest without recourse to stress. Methods and Results-Patients with varying degrees of coronary artery stenosis on quantitative angiography underwent high-mechanical-index myocardial contrast echocardiography at 15 Hz to allow measurement of phasic changes in aBV in large intramyocardial vessels using either Definity (group 1; nϭ22) or Imagent (group 2; nϭ22). Progressive increases in the background-subtracted systolic/diastolic aBV signal ratio were noted between each level none, mild [Ͻ50%], moderate [50% to 75%], and severe [Ͼ75%]) of stenosis severity for both group 1 (0.09Ϯ0.13, 0.13Ϯ0.08, 0.58Ϯ0.22, and 0.77Ϯ0.40; PϽ0.001) and group 2 (0.10Ϯ0.05, 0.27Ϯ0.18, 0.39Ϯ0.28, and 0.74Ϯ0.37; PϽ0.0001) patients. A systolic/diastolic aBV signal ratio of Ͼ0.34 provided a sensitivity and specificity of 80% and 71%, respectively, for the detection of Ͼ75% coronary stenosis in group 1 patients, whereas a ratio of Ͼ0.43 provided a sensitivity and specificity of 89% and 74%, respectively, for the detection of Ͼ75% stenosis in group 2 patients. Conclusions-Both the presence and severity of a physiologically significant coronary stenosis can be detected at rest by measuring the increase in aBV on myocardial contrast echocardiography that occurs distally to the stenosis without recourse to any form of stress. (Circulation. 2005;112:1154-1160.)