Detecting and excluding significant left main coronary artery narrowing by echocardiography.

Two-dimensional echocardiography (2-D echo) of the left main coronary artery (LMCA) was attempted in 50 patients undergoing arteriography to evaluate 2-D echo for recognition of significant stenosis of the LMCA. Although the echocardiographer was experienced and used rigorous technique, visualization of the LMCA adequate for making a judgment regarding lumen reduction was possible in only 37 patients (74%). Of the 10 studies with suspected positive findings for LMCA stenosis by 2-D echo, 4 yielded true-positive and 6 false-positive results. A study from 1 other patient with LMCA stenosis by angiography was erroneously interpreted as negative by 2-D echo. Analysis of arteriograms in the 6 patients with false positive 2-D echo readings failed to implicate significant proximal left anterior descending artery narrowing as the cause of the errors. Although 2-D echo was correct in indicating the presence or absence of LMCA stenosis in 30 of 37 patients, and the predictive value of a negative 2-D echo response was 96%, the noninvasive method appears to be inadequate as a screening test. Widespread use of the procedure is limited by the 26% failure rate for adequate studies in experienced hands, and the implications of the occasional false-negative finding. If LMCA stenosis is suspected by 2-D echo in a patient who needs arteriography, the special care given to this possibility by the arteriographer should not harm the patient.