Dipyridamole-echocardiography in coronary artery disease

Regional wall motion impairment incurred by means of dipyridamole-induced ischemia, is regarded with higher sensitivity and specificity than the conventional findings in the ECG. Based on the latter considerations, a new test, the dipyridamole echocardiogram has been introduced in which the development of regional wall motion impairment is designated as the positive diagnostic criterion. Dipyridamole is a vasodilator of coronary arterioles. During the course of the examination, three consecutively occurring mechanisms are considered responsible for the appearance of dipyridamole-induced ischemia in the presence of coronary stenosis. The ischemia is initially attributed to a steal-effect, then to reflex-induced rise in rate-pressure product and, lastly, to a vasospastic component. In 680 patients with thoracic pain, on use of 0.84 mg/kg over ten minutes, there was a sensitivity of 74% in detection of angiographically-documented coronary artery disease, defined as greater than 70% stenosis in at least one major coronary artery, and a specificity of 95%. The onset of regional wall motion impairment after dipyridamole infusion was correlated with the severity of the disease, the localization of the wall motion impairment enabled delineation of the localization of the stenosis in the coronary vascular system. By means of the dipyridamole echocardiogram, the effectiveness of therapeutic measures such as PTCA, ACVB, medical antianginal treatment and thrombolysis can be assessed. Lastly, the dipyridamole echocardiogram provides important information with regard to prognosis.