Hydrogen peroxide contrast echocardiography: quantification in vivo of myocardial risk area during coronary occlusion and of the necrotic area remaining after myocardial reperfusion.

Abstract

During sustained coronary occlusion in canine preparations, the extent of regions that fail to show contrast enhancement when imaged by supra-aortic hydrogen peroxide contrast echocardiography (SHPCE) has been shown to correlate well for single cross sections with the extent of malperfused myocardium "at risk" of infarction. In the present study, SHPCE was investigated as a means of determining the fraction of total left ventricular mass at risk during occlusion. Since necrotic tissue has low blood flow even when reperfused, we also investigated the potential of quantitating the extent of infarcted myocardium by measuring the extent of contrast defects seen with SHPCE performed during reperfusion. In 20 dogs the fraction of the left ventricle showing a contrast defect during coronary occlusion correlated well with the fraction of the left ventricular mass "at risk" by an autoradiographic technique (autoradiography = 0.83 echocardiography + 8.6%; r = .89, SEE = 4.5%). SHPCE was also performed after 3 hr of reperfusion following occlusions varying in duration from 60 to 150 min. The fraction of the ventricle showing a contrast defect during reperfusion predicted the infarcted portion of the left ventricle as shown by triphenyl tetrazolium chloride staining (% left ventricle infarcted = 0.81 echocardiography + 3.3%; r = .84, SEE = 5.3%). Observer variability for the fraction of the ventricle showing a contrast defect was excellent during both occlusion and reperfusion. The ratio of the left ventricular extent of contrast-negative regions during reperfusion and occlusion was used to calculate a necrosis-to-risk index in vivo that correlated relatively well with the myocardial necrosis-to-risk ratio determined morphologically (r = .77, SEE = 16%).(ABSTRACT TRUNCATED AT 250 WORDS)