Background: Previous studies have shown that carotid intima-media thickness correlates well with the presence and extent of coronary artery disease. This study was conducted to determine whether it could reliably predict the presence of left main coronary artery disease.
Methods: Common carotid intima-media thickness was measured in 50 patients with angiographically proven significant (> or =50%stenosis) left main coronary artery disease and in another 50 age- and sex-matched patients with coronary artery disease without the involvement of the left main coronary artery. Measurements of the carotid intima-media thickness were made on the far wall 1 cm from the distal end of the common carotid artery bilaterally, and the average and the greater of the two values thus obtained for each patient were used for analysis. Plaques were not included in the measurement of carotid intima-media thickness.
Results: The average and greater of the two values were significantly higher in patients with left main coronary artery disease as compared to those without it (average intima-media thickness: 0.926 +/- 0.12 vs. 0.78 9 +/- 0.16 mm; p< 0.001; greater intima-media thickness: 0.994 +/- 0.13 vs. 0.844 +/- 0.20 mm; p< 0.001). The cut-off values of 0.81 mm for the average carotid intima-media thickness and 0.87 mm for the greater carotid intima-media thickness were found to have optimum sensitivity (92% and 90%, respectively) and specificity (60% and 64%, respectively) for the detection of left main coronary artery disease. A higher cut-off value of 1.0 mm increased specificity to 92% and 84%, respectively, for the average and greater thicknesses, but sensitivity decreased markedly.
Conclusions: There is a significant association between increased carotid intima-media thickness and the presence of left main coronary artery disease. The measurement of carotid intima-media thickness can be used with reasonably good sensitivity and specificity for the detection of left main coronary artery disease in patients who are undergoing evaluation for suspectedcoronary artery disease.