Evaluation of left main coronary artery stenosis by transthoracic echocardiography.

OBJECTIVE

We sought to demonstrate left main coronary artery (LM) stenosis by transthoracic echocardiography.

BACKGROUND

Evaluation of LM stenosis was done mostly by transesophageal echocardiography in patients with coronary artery disease.

METHODS

A total of 1456 patients with coronary artery disease were studied, of which 801 patients (55%) had adequate coronary flow assessment. The LM and the adjacent segments of left anterior descending coronary artery and left circumflex coronary artery were evaluated by color flow and Doppler. Mosaic flow and/or peak diastolic velocity of greater than or equal to 1.5 m/s was considered abnormal. These findings were correlated with stenoses at coronary angiography. A total of 40 patients who had abnormal diastolic flow in LM by transthoracic echocardiography constituted group 1 and 56 patients with normal LM flow constituted the control group (group 2).

RESULTS

The peak diastolic velocities in LM in group 1 ranged between 1.5 and 4.4 m/s (mean 2.11 +/- 0.78 m/s). Of the 40 patients in group 1, 34 had significant LM stenosis by coronary angiography (sensitivity of 85%, positive predictive value 82.5%). The velocities in LM in group 2 ranged between 0.4 and 1.2 m/s (mean 0.66 +/- 0.25 m/s). In all, 49 of 56 patients in this group had normal LM on coronary angiography (88% specificity, negative predictive value 90.7%). The remaining 7 had distal LM stenosis. Mosaic flow in LM indicated significant LM stenosis in 85% of patients, whereas normal flow in LM did not rule out distal LM stenosis in 12% of patients.

CONCLUSIONS

LM stenosis could be assessed by transthoracic echocardiography with an acceptable degree of sensitivity and specificity.