Three-dimensional myocardial contrast echocardiography using Quantison Depot®, a new contrast agent: An experimental study with implications for the cardiac catheterization laboratory

The aim of this study was to determine whether a new deposit agent (Quantison Depot®, Andaris, UK) would provide accurate information regarding risk area during coronary occlusion and infarct size after reperfusion when combined with 3-dimensional echocardiography (3DE). This agent is composed of air-filled albumin shells with a mean size of 10 μm which gets lodged within the microcirculation producing intense myocardial opacification. 3DE was performed with a Tomtec rotational device. Quantison Depot® (0.4 mg·kg^-1) was injected into the left atrium of 8 dogs during coronary occlusion (when ^99mTc as also injected for autoradiography) and 2-4 hours after reperfusion. The heart was breadloafed into 0.9 mm slices for the assessment of risk area by ^99mTc autoradiography and infarct size by triphenyl tetrazolium chloride (TTC) tissue staining. Images corresponding to the heart slices were reconstructed from the 3DE data. From these images, risk and infarct volumes were calculated for all techniques. An excellent correlation was noted between 3DE and ^99mTc autoradiography for assessment of risk volume (y=l. 02x + 1.1, r=0.89, p<0.001, SEE=2.5) , and between 3DE and TTC for assessment of infarct volume (y=0.97x +0.4, r=0.87, p,0.001, SEE=1.7). Despite hemodynamic instability during coronary occlusion and reperfusion, these deposit microbubbles caused no additional hemodynamic changes in the dose used. It is concluded that Quantison Depot®, in conjunction with 3DE, can provide unique information pertaining to the entire left ventricle during coronary occlusion and reperfusion without any adverse effects. These results suggest important applications of this approach in the cardiac catheterization laboratory, particularly in patients undergoing interventions during acute myocardial infarction.