Hyperemic response of intracoronary contrast agents during two-dimensional echographic delineation of regional myocardium.
Several intracoronary echo contrast agents that provided satisfactory regional myocardial delineation with two-dimensional echocardiography were compared in 15 dogs and their effects on coronary blood flow were examined. Reproducible delineation of myocardium subserved from the intracoronary echo contrast injection site was achieved with hand-agitated agents containing greater than or equal to 30% Renografin, greater than or equal to 30% glucose, greater than or equal to 30% sucrose or 6% dextran. After a 2 cc injection of the echo contrast agent, peak hyperemic augmentation of coronary flow was 56.7 +/- 54.4% for 6% dextran, 116.0 +/- 71.1% for 30% Renografin, 119.3 +/- 47.8% for 30% sucrose, 173.8 +/- 38.3% for 30% glucose. Although, 6% dextran resulted in the lowest and shortest hyperemic response of the four agents, computer-derived echo contrast appearance-disappearance analysis indicated a prolonged myocardial contrast decay half-life (21.0 seconds). On the other hand, 30% Renografin had a more rapid myocardial echo contrast washout (T 1/2 = 15.5 seconds), but a significantly greater hyperemic effect was observed. It is concluded that development of echo contrast agents for myocardial contrast two-dimensional echocardiographic assessment of myocardial perfusion will require consideration of alterations in coronary flow due to contrast-induced hyperemia.