Hydrogen peroxide contrast--enhanced two-dimensional echocardiography: real-time in vivo delineation of regional myocardial perfusion.

Abstract

I.v. injection of hydrogen peroxide (HP) produces O2 microbubbles suitable for echocardiographic contrast enhancement. This study evaluates HP contrast-enhanced 2 dimensional echocardiography (2DE) during acute coronary occlusion in a canine model by comparison with perfusion indicated by antemortem monastral blue (MB) staining, postmortem triphenyltetrazolium chloride (TTC) infarct sizing and abnormal wall motion (AWM). Injections of a fresh mixture of 1 to 2 ml 0.3% HP and 1 ml blood were made in 10 closed-chest dogs 6 h after coronary ligation and short-axis 2DE images were made at 4 anatomic levels. Optimal preinjection 2DE settings were determined by interaction with an on-line, color-coded, videodensitometer system. The circumferential extent of 2DE contrast defect (ECD) was strongly predictive of the pathologic extent of malperfusion (MB = 0.94 ECD + 4.7%, SEE = 7.7%, r = 0.93) and of infarction (TTC = 0.84 ECD + 5%, SEE [standard error of the estimate] = 9.4%, r = 0.89). Moreover, ECD was superior to wall motion abnormality in predicting the extent of both malperfusion and infarction (MB = 0.85 AWM + 0.5%, SEE = 13.1%, r = 0.78; TTC = 0.77 AWM - 0.2%, SEE = 13.5%, r = 0.75). No adverse hemodynamic effects were seen after HP injection. This study validates the use of HP contrast-enhanced 2DE as a readily repeatable, accurate, in vivo real-time method of quantifying the extent of abnormal regional myocardial perfusion during acute myocardial infarction. Apparently, further study is warranted to determine if myocardial contrast adequate to define regional perfusion can be obtained safely by this method in man.