DETECTION OF MYOCARDIAL PERFUSION DEFECTS BY CONTRAST ECHOCARDIOGRAPHY IN THE SETTING OF ACUTE MYOCARDIAL-ISCHEMIA WITH RESIDUAL ANTEGRADE FLOW

Although myocardial contrast echocardiography accurately demarcates ar ea at risk during total coronary occlusion, the ability of MCE to deli neate area at risk in the presence of residual antegrade flow is unkno wn. We hypothesized that perfusion defects in myocardial segments supp lied by severe coronary stenoses with residual antegrade flow could be detected by MCE using intravenous FS069. We studied 13 open-chest dog s using an intravenous injection of FS069 during intermittent harmonic imaging. Images were collected at baseline, during acute ischemia wit h residual antegrade flow, physiologic hyperemia (release of stenosis) , and total coronary occlusion. Regional myocardial blood from was ass essed using colored microspheres. MCE risk area during acute ischemia with residual antegrade flow and total occlusion was planimetered and compared with pathologic risk area (area unstained by monastral blue). Background-subtracted peak video-intensity in the risk area was asses sed for all flow states. Regional myocardial blood flow confirmed expe cted flow states, being significantly greater during physiologic hyper emia (4.16 +/- 1.22 ml/min/g) than at baseline (0.71 +/- 0.19 ml/min/g ) and significantly diminished during coronary stenosis with residual antegrade flow (0.20 +/- 0.16 ml/min/g) and total occlusion (0.09 +/- 0.06 ml/min/g; P < 0.0001). Myocardial risk area by MCE during coronar y stenosis with residual antegrade flow correlated well with pathologi c risk area determined by monastral blue staining (r = 0.86). Peak vid eointensity during coronary stenosis (111 +/- 27) was significantly le ss than at baseline (157 +/- 50) but greater than during total occlusi on (81 +/- 34; P < 0.0001). In conclusion, intravenous FS069 in conjun ction with intermittent harmonic imaging delineates area at risk in is chemic myocardium supplied by a coronary stenoses with residual antegr ade flow. The presence of a perfusion defect on MCE does not necessari ly imply that the coronary artery is totally occluded.