938-56 Myocardial Contrast Echocardiography: What is the Meaning of Regional Perfusion Abnormalities After Release of Temporary Coronary Occlusions?

Abstract

Myocardial contrast echocardiography (MCE) has been used to demonstrate regional perfusion abnormalities (RPA) in the presence of coronary occlusions, severe coronary stenosis, and myocardial infarctions (MI). We have observed such abnormalities following the release of a temporary occlusion in the absence of MI. To further define this, we studied 54 open-chest dogs. Temporary coronary occlusions were performed (Group A = 15 minutes; Group B = 30 to 360 minutes), followed by release of the occlusions and by the administration of dobutamine IV (10 μg/kg/min). Myocardial contrast echocardiography was performed with aortic root injections of sonicated albumin (Albunex ® ) during occlusion and following reperfusion with and without dobutamine. Postmortem TTC staining (+ stain = viable myocardiuml was used to determine the presence/absence of MI All Group A dogs (n = 14) showed no evidence of MI. In Group B (n = 40), 14 dogs showed no evidence of MI, whereas the other 26 did (12 papillary muscle, 7 subendocardial, and 7 transmural). The presence of RPA in all groups is shown below: Occlusion Reperfusion Reperfusion+ Dobutamine Group A 13/14 2/14 2/14 Group B 35/40 17/39 20/39 • No MI 11/14 7/13 8/13 • Papillary MI 10/12 3/12 5/12 • Subendocardial MI 7/7 3/7 3/7 • Transmural MI 7/7 4/7 4/7 In conclusion, the presence of a RPA following the release of coronary occlusions most likely indicates abnormal coronary reserve rather than the presence of myocardial necrosis.