Doppler and two-dimensional echocardiographic assessment of left ventricular function before and after intravenous dipyridamole stress testing for detection of coronary artery

Abstract

Thallium perfusion imaging following the intravenous infusion of dipyridamole, a potent coronary vasodilator, has been demonstrated to be useful in the evaluation of the functional significance of coronary artery disease (CAD). While recent studies have demonstrated that 2-dimensional echocardiographic monitoring of left ventricular (LV) function after intravenous dipyridamole has a sensitivity somewhat less than that of thallium perfusion imaging, none has examined the usefulness of Doppler evaluation of aortic blood flow in this setting. One hundred patients undergoing dipyridamolethallium imaging for clinical indications were studied. Technically adequate Doppler echocardiographic studies were obtained in 97 patients. LV ejection fraction, peak aortic velocity and acceleration, as well as segmental LV wall motion, were analyzed before and at peak dipyridamole effect. Thallium perfusion images were normal in 41 and abnormal in 53 patients studied. A statistically significant difference in percent change from baseline to peak dipyridamole effect in velocity, acceleration and ejection fraction was seen between the 2 groups (26 vs −2%, 51 vs −2% and 16 vs 4%, respectively, all p < 0.05). Comparison of 2-dimensional wall motion analysis to thallium yielded a sensitivity and specificity of 74 and 80%, respectively. In the group of patients who underwent cardiac catheterization, 2-dimensional wall motion analysis yielded a sensitivity of 64% in the detection of CAD. The combination of 2-dimensional and Doppler echocardiographic parameters increased the sensitivity in the detection of CAD to 85%. The combination of the 2 techniques was particularly sensitive in the detection of multivessel CAD with significant differences in percent change from baseline to peak dipyridamole effect in velocity, acceleration and ejection fraction observed between those with and without multivessel CAD. Thus, the addition of Doppler evaluation of aortic blood flow velocities to standard 2-dimensional echocardiographic imaging appears to add significantly to the sensitivity of this technique and is furthermore applicable in most patients studied. These data indicate that cardiac ultrasound examination before and after intravenous administration of dipyridamole may be a reasonable alternative to thallium perfusion imaging in clinical settings for detection and functional assessment of patients with CAD.