Contrast echocardiographic estimation of regional myocardial blood flow after acute coronary occlusion

Abstract

Contrast echocardiography can predict pathologic area at risk during acute coronary occlusion. In this study we evaluated whether the intensity and timing of contrast appearance in ischemic regions can provide a quantitative measure of residual myocardial perfusion, and whether changes in these parameters observed after serial injections reflect changes in blood flow to acutely ischemic tissue. Supra-aortic hydrogen peroxide contrast echocardiography was performed in 12 consecutive dogs at 1, 20, and 120 min after acute circumflex coronary occlusion. Contrast enhancement was determined qualitatively with a segmental four-point scoring system based on the appearance time and peak perceived intensity of contrast enhancement and quantitatively with a computer algorithm designed to reflect these parameters. Comparison was made in each segment to concomitant radioactive microsphere blood flow. Qualitative scoring related systematically to normalized segmental blood flow (3+ = 93%; 2+ = 61%; 1+ = 32.%; 0 = 18%; p< .01 for each adjacent value), as did quantitative analysis including all segments (r = .78; p< .01) and isolated to the ischemic region (flow = 1.13 intensity change + 6.8%; r = .83, p< .001). Changes in microsphere flow in ischemic regions between sequential observations were correlated with changes in qualitative score (r = .88, p < .001) and results of quantitative analysis (r = 0.70, p< .01). The amount of contrast enhancement can provide quantitative information about residual myocardial blood flow in ischemic regions and can also be used to track changing patterns of flow in vivo after acute coronary occlusion.