Doppler echocardiographic approach to the blood flow of the left anterior descending coronary artery

Assessment of flow in the left anterior descending coronary artery by Doppler echocardiography appeared to be possible in some patients in which the coronary artery system might be wide and/or the displacement of the coronary artery might be reduced because of cardiac enlargement or of impaired cardiac function. A study of this possibility was carried out in 78 patients, 20 cases with hypertrophic cardiomyopathy, 10 with dilated cardiomyopathy, 20 with aortic valve disease, and 28 following valve replacement for aortic valve disease. The anterior interventricular sulcus was a helpful landmark to search for the left anterior descending artery. The characteristic feature of the coronary flow pattern, that the flow ran mainly during diastole, was also helpful in finding the coronary artery. Complementary roles of ultrasonic imaging and Doppler ultrasound evaluation should be emphasized for identifying a thin echo-free space in the sulcus as the coronary artery. The left anterior descending coronary artery was imaged in 26 of the 78 patients. The peak velocity ranged 24 cm/s to 75 cm/s in different patients. Because the present study was carried out in patients with some particular diseases, these results do not indicate that current techniques can be routinely used for assessing the coronary flow. The detection rate will be increased with improvements in image resolution and the Doppler sensitivity. Although the detection rate of the coronary artery was not satisfactory in the present stage, the effect of sublingual administration of nitroglycerin on coronary circulation was noninvasively assessed in some patients, where reduction of the flow velocity by about 27% was observed in real time.