Quantitative assessment of myocardial perfusion during graded coronary artery stenoses by intravenous myocardial contrast echocardiography.
OBJECTIVE
The purpose of this study was to examine whether coronary stenoses of variable severity could be quantitatively assessed by analysis of myocardial perfusion as determined by intravenous (IV) myocardial contrast echocardiography.


BACKGROUND
Recently, new contrast agents and imaging technology have been developed that may enable improved assessment of myocardial perfusion by IV contrast injection.


METHODS
Variable obstruction of the left anterior descending (LAD) coronary artery in dogs was produced by a screw occluder. Coronary artery flow was measured with a transit time flowmeter during baseline, pharmacological vasodilation, a non-flow-limiting stenosis at rest in conjunction with vasodilation, a flow-limiting stenosis, and total occlusion. Myocardial contrast echocardiography was performed after IV injection of the contrast agent NC 100100. Time-intensity curves were obtained off-line for the LAD risk area and the adjacent left circumflex (LCx) territory, and peak background-subtracted video intensity was determined. Fluorescent microspheres were injected at each intervention for determination of regional myocardial blood flow.


RESULTS
During non-flow-limiting stenosis, flow limiting stenosis and total occlusion, LAD/LCx ratios of peak myocardial videointensity and blood flow decreased proportionately. Both LAD/LCx ratios of video intensity and blood flow identified the non-flow-limiting and the flow-limiting stenoses as well as total occlusion of the LAD artery. A significant correlation between LAD/LCx video intensity and blood flow ratios was observed (r = 0.83, p < 0.0001).


CONCLUSIONS
The degree of blood flow mismatch between ischemic and normal myocardial regions during graded coronary stenoses can be estimated in the dog by quantitative assessment of myocardial perfusion produced by IV myocardial contrast echocardiography.
Leistad
E
E
Cardiovascular Division, University of California at San Diego, 92103-8411, USA.
Ohmori
K
K
Peterson
T A
TA
Christensen
G
G
DeMaria
A N
AN
D000818:Animals; D003287:Contrast Media; D003326:Coronary Circulation / Q000502:physiology*; D003327:Coronary Disease / Q000000981:diagnostic imaging* / Q000503:physiopathology; D004285:Dogs; D004452:Echocardiography; D005290:Ferric Compounds; D007501:Iron; D009203:Myocardial Infarction / Q000000981:diagnostic imaging* / Q000503:physiopathology; D010087:Oxides; D012039:Regional Blood Flow / Q000502:physiology; D012680:Sensitivity and Specificity
D003287:Contrast Media; D005290:Ferric Compounds; D010087:Oxides; C069727:Sonazoid; D007501:Iron