CORRELATION BETWEEN QUANTITATIVE ANGIOGRAPHIC LESION SEVERITY AND MYOCARDIAL CONTRAST INTENSITY DURING A CONTINUOUS-INFUSION OF PERFLUOROCARBON-CONTAINING MICROBUBBLES

The purpose of this study was to determine whether quantitative measur ements of myocardial video-intensity (MVI) during continuous intraveno us infusions of microbubbles could detect differences in coronary arte ry stenosis severity during dobutamine stress echocardiography. Corona ry artery stenoses were created in seven dogs by progressively tighten ing a snare around the coronary artery. Intravenous infusions of perfl uorocarbon microbubbles were given during dobutamine stress. The initi al rate of myocardial contrast enhancement (slope), peak myocardial co ntrast (peak MVI) at the longest pulsing interval, and the product (sl ope peak MVI) were compared as ratios in the stenosed versus adjacen t normal perfusion beds. Twenty-two coronary stenoses were compared (r ange 16% to 80% in diameter). There was a strong correlation between b oth slope ratios and slope peak MVI ratios and percent stenosis (r = -0.89 for both, p < 0.001). The rate of contrast replenishment during a continuous infusion of microbubbles can be used to determine both t he presence and severity of coronary stenoses during stress echocardio graphy.