DIPYRIDAMOLE MYOCARDIAL CONTRAST ECHOCARDIOGRAPHY IN PATIENTS WITH SINGLE-VESSEL CORONARY-ARTERY DISEASE - PERFUSION, ANATOMIC, AND FUNCTIONAL CORRELATES

The aim of this study was to examine whether myocardial contrast echocardiography (MCE) may be used to study regional myocardial blood flow distribution during dipyriamole-induced hyperemia. MCE was performed before and after dipyridamole infusion in 11 patients with a proximal, significant left anterior descending (LAD) coronary artery stenosis. The relation between contrast-derived parameters and the degree of coronary narrowing and the occurrence of transient regional wall motion abnormalities was also investigated. In the territory supplied by left circumflex coronary artery, mean peak contrast intensity increased after dipyridamole from 50 +/- 18 to 76 +/- 27 IU (p < 0.001). In contrast, a significant reduction in mean peak intensity was observed after dipyridamole in the LAD territory (from 41 +/- 27 to 13 +/- 13 IU, p < 0.01). Similar results were obtained with the use of the area under the time-intensity curve. An increase in peak intensity greater than or equal to 10 IU after dipyridamole administration separated normal regions from those supplied by a significant coronary artery lesion with a sensitivity of 91% and a specificity of 91%. Perfusion abnormalities were always detected by contrast echocardiography when septal motion abnormalities developed and, in five patients they were detected in the absence of clinical, electrocardiographic, and echocardiographic signs of ischemia. A weak correlation was found between both peak intensity and area under the curve and percent coronary diameter stenosis and cross-sectional area. In conclusion, dipyridamole MCE can be used during routine coronary angiography to assess myocardial blood flow distribution in patients with coronary artery disease. The intracoronary injection of contrast agents during dipyridamole stress echocardiography, may provide additional information on the functional significance of coronary lesions, thus helping in prognostic stratification and therapeutic decision making.