IMAGING OF THE DISTAL LEFT ANTERIOR DESCENDING CORONARY-ARTERY BY TRANSTHORACIC COLOR-DOPPLER ECHOCARDIOGRAPHY

Two-dimensional echocardiography evaluates the effect of myocardial is chemia on left ventricular wall motion, but a direct measure of corona ry flow by this method is still lacking. The aim of the present study is to evaluate the efficacy of new, high-resolution ultra-sound equipm ent designed to image by color Doppler transthoracic echocardiography the epicardial and intramural coronary vessels. We have studied 33 con secutive patients in apical projections, to detect by color Doppler gr eater than or equal to 1 segments of the middle-distal tract of the le ft anterior descending coronary artery. In 25 of 33 patients (76%), th e middle-distal tract of the left anterior descending coronary artery was imaged by color Doppler. In 15 of 33 patients (46%), the periapica l tract of the left anterior descending was imaged along with its perf orating branches. In 2 of 4 patients who had coronary artery bypass gr afting, the anastomosis between the left internal mammary artery and t he left anterior descending coronary artery was imaged. Once the coron ary artery was imaged, pulsed Doppler was used to measure coronary blo od flow velocity at rest. Peak and mean flow velocity, as well as the deceleration time (msec) and deceleration rate (cm/sec(2)), were measu red on the diastolic phase of the Doppler tracing. In all 25 patients, it was possible to measure by pulsed Doppler the coronary flow veloci ty pattern characterized by a typical prevalent diastolic component. P eak diastolic Flow velocity was 50 +/- 17 cm/sec and mean diastolic Fl ow velocity was 37 +/- 12 cm/sec. The deceleration time was 916.2 +/- 429.1 msec and the deceleration rate was 86.3 +/- 69.3 cm/sec2. The Do ppler pattern of the grafted mammary artery was different from the nat ive mammary flow. This new noninvasive imaging technique of the corona ry arteries promises to expand the field of diagnostic and experimenta l echocardiography and brings new insight into the pathophysiology of ischemic heart disease. (C) 1998 by Excerpta Medica, Inc.