Contrast perfusion echocardiography: Distribution and reproducibility of myocardial contrast enhancement in coronary artery disease

Abstract

A qualitative assessment was undertaken of the echocardiographic distribution of myocardial contrast enhancement after selective intracoronary injections of 2 ml of hand-agitated Urografin ® solution. The reproducibility and duration of contrast enhancement has also been examined. Forty-five contrast injections were given, 36 into the left and 6 into the right coronary arteries and 3 into bypass grafts of 28 patients undergoing diagnostic arteriography. Myocardial contrast enhancement occurred in 91% of cases. Although contrast enhancement appeared within the expected area of distribution of the artery infused, in no case was enhancement homogeneous. In 4 patients (1 of whom had undergone coronary bypass surgery), contrast enhancement also appeared in areas remote from the expected perfusion territory, in each case due to well established collateral supply seen angiographically. The contrast effect persisted for 71 ± 26 seconds. Repeat injection in 5 patients (using identical echocardiographic windows) confirmed the reproducibility of the technique. No patient had symptoms related to the injections, although transient left ventricular wall motion abnormalities were observed in 3 cases. High-grade coronary stenoses did not affect distribution of myocardial contrast enhancement, although coronary occlusions produced well defined deficits. Thus, selective intracoronary injections of hand-agitated echocardiographic contrast medium produce regional myocardial enhancement, which probably reflects the perfusion territory of the artery. The technique is safe and reproducible in human subjects. Nevertheless, because regional enhancement after selective coronary injections is not homogeneous, analysis of enhancement deficits is unlikely to provide a clinically useful means of evaluating the functional significance of coronary stenoses.