Contrast echocardiography can assess risk area and infarct size during coronary occlusion and reperfusion: experimental validation

Objectives We sought to validate the ability of real-time myocardial contrast echocardiography (MCE) measures of opacification defect and contrast refilling parameters to estimate risk area (RA) and infarct area (IA) during coronary occlusion and reperfusion. Background No data exist establishing the accuracy of MCE in determining RA and IA size. We hypothesized that in the setting of coronary occlusion, MCE should identify RA as a perfusion defect early after bubble destruction, collateral flow to viable myocardium as opacification late during refilling and IA as absent opacification. Methods Three hours of coronary occlusion and reperfusion were each produced in 11 dogs in which real-time MCE was performed during intravenous infusion of Sonovue (Bracco). Real-time contrast echocardiography was performed at baseline, during occlusion and reperfusion. Early (BEGIN) and end (END) images from a FLASH refilling sequence were acquired, as well as late refilling images (LATE) 1 min after FLASH. Real-time contrast echocardiography defect size and quantitative refilling parameters were compared with RA and IA determined by tissue staining. Results During occlusion, defect size varied with refilling time; defects from BEGIN images correlated best to RA and those from LATE images to IA. Refilling parameters, but not LATE peak intensity, did not predict the IA size during occlusion. During reperfusion, defects from BEGIN images were well correlated to RA and END images to IA, whereas peak plateau intensity and refilling slope parameters predicted IA size. Conclusions Real-time contrast echocardiography defect size varies throughout microbubble refilling. Appropriately selected defect sizes and refilling parameters provide estimates of RA and IA during coronary occlusion and reperfusion.