TRANSTHORACIC ECHOCARDIOGRAPHIC DETECTION OF CORONARY ATHEROSCLEROSIS

Coronary atherosclerosis is a pathologic process that produces thicken ing of the walls of the coronary arteries to the point that flow throu gh those vessels may be impaired. This study attempts to use transthor acic echocardiography to detect coronary atherosclerosis. Eighty-nine patients undergoing coronary angiography were examined with a broad-ba nd ultrasonic transducer with a frequency between 3 and 5 MHz. A modif ied short-axis examination was utilized to identify left main and prox imal left anterior descending arteries. The examination wets recorded digitally and displayed in a 32-cell, quad screen cine loop. Fifty-six of the 89 patients (63%) had obstructive coronary artery disease (CAD ) (i.e., at least 1 vessel with 50% obstruction). There were 14 patien ts with CAD but no vessel had greater than or equal to 50% obstruction . Nineteen patients (21%) had angiographically normal arteries. The co ronary echograms were judged qualitatively for brightness, uniformity, and persistence (defined as the ability to see segments of the artery walls in more frames than other segments). The length of the coronary artery visualized, the width of the left main coronary artery, and th e width of the thickest segment of the coronary artery walls were quan titatively measured. More than 2 cm of the left coronary artery was se en in almost all patients. Segmental changes were noted in 52 of the 5 6 patients with obstructive CAD, 12 of the 14 patients with nonobstruc tive CAD, and 3 of the 19 patients with normal arteries. Persistence g reatly enhanced the ability to judge the segmental changes. Forty-six patients with obstructive disease had wall thickness greater than or e qual to 1.5 mm. Only 6 patients with nonobstructive coronary arteries had this wall thickness, and only 1 normal subject had thick walls. Th e ultrasonic findings were useful in predicting the presence or absenc e of coronary atherosclerosis to varying degrees of sensitivity and sp ecificity based on the segmental findings and wall thickness measureme nts, The results of this study indicate that a transthoracic ultrasoni c examination of the proximal left coronary artery could be a clinical ly valuable tool in the qualitative identification of coronary atheros clerosis.