TRANSTHORACIC
ULTRASOUND WITH HARMONIC IMAGING- CAN CORONARY ATHEROSCLEROSIS BE IDENTIFIED? U.V Premawardhana* and D.S.
Celermajer. Cardiology Department, Royal
Prince Alfred Hospital, Sydney, NSW. Non-invasive detection of
obstructive coronary disease would represent a major advance in cardiovascular
diagnostics. Recent developments in transthoracic echocardiography, including
harmonic imaging and rapid frame rates, have allowed routine identification of
coronary artery anatomy in neonates. We assessed whether such images might
provide diagnostic coronary information in adults with chest pain syndromes and
possible atherosclerosis. Fifty consecutive subjects
presenting for elective coronary angiography were studied on the day of their
procedure using a 256-channel digital high-resolution ultrasound system
(Vingmed System V) and 1.7MHz harmonic imaging to optimise 2D picture quality.
The ultrasonographer was blinded to the angiographic results. A standard
protocol using modified parasternal short and long axis, as well as apical
4-chamber views was used, to image left main (LMCA) and right coronary (RCA)
origins as well as the proximal left anterior descending, left circumflex and
right coronary vessels. Image quality was scored as 0 for not obtained, 1 for
poor images, 2 for fair and 3 for good quality images for each of the
prespecified coronary segments. 39 males and 11 females aged
61+ 12 years were studied. On angiography, 18 had no obstructive lesions, 10
had single vessel, 11 had double vessel and 11 had triple vessel disease. Scans
took 18.5 +5 minutes to acquire. Image quality was best for proximal RCA
(score 1.8 + 0.7) and LMCA (score 1.9+ 0.8) but were not
routinely obtainable. More distal views all had average scores <1.2. Body
size, co-existing lung disease, aortic calcification, cardiac motion and
overlapping structures were the major limitations encountered. Obstructive
coronary disease could not be reliably identified. Ten subjects with known left
main disease were then scanned by echocardiography, and obstructive stenoses
were confidently identifiable in only 3 of these 10 cases. These
data suggest that, even with advanced imaging capability, transthoracic
ultrasound cannot currently provide accurate diagnostic information concerning
coronary atherosclerosis.
