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 echoc ardiography (MCE) may be used to study regional myocardial blood flow distribution during dipyriamole-induced hyperemia. MCE was performed b efore and after dipyridamole infusion in 11 patients with a proximal, significant left anterior descending (LAD) coronary artery stenosis. T he relation between contrast-derived parameters and the degree of coro nary narrowing and the occurrence of transient regional wall motion ab normalities was also investigated. In the territory supplied by left c ircumflex coronary artery, mean peak contrast intensity increased afte r dipyridamole from 50 +/- 18 to 76 +/- 27 IU (p < 0.001). In contrast , a significant reduction in mean peak intensity was observed after di pyridamole 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 e qual to 10 IU after dipyridamole administration separated normal regio ns from those supplied by a significant coronary artery lesion with a sensitivity of 91% and a specificity of 91%. Perfusion abnormalities w ere always detected by contrast echocardiography when septal motion ab normalities 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 c ross-sectional area. In conclusion, dipyridamole MCE can be used durin g routine coronary angiography to assess myocardial blood flow distrib ution in patients with coronary artery disease. The intracoronary inje ction of contrast agents during dipyridamole stress echocardiography, may provide additional information on the functional significance of c oronary lesions, thus helping in prognostic stratification and therape utic decision making.