Objectives: This study investigated the diagnostic accuracy of carotid ultrasonography in screening for significant coronary artery disease (% diameter stenosis > or = 75%).
Methods: Five hundred sixty patients (342 males, 218 females, mean age 66.4 years) underwent both coronary angiography and carotid ultrasonography. Gensini's coronary score was calculated as a quantitative parameter of coronary atherosclerosis. The most hypertrophic intimal-medial complex thickness (IMT) of the bilateral common carotid arteries (distal and proximal to the echo probe in each artery) was measured within 2 or 3 cm from the carotid bifurcation. The mean IMT (mean of these 4 sites), the maximum IMT (maximum of these 4 sites), and number of plaques (localized hypertrophy of IMT > or = 1.1 mm) were calculated as a quantitative parameter of carotid atherosclerosis.
Results: The screening parameters were determined as 0.85 mm mean IMT, 1.1 mm maximum IMT, and at least 2 sites of plaque. The sensitivity, specificity and accuracy rate for the detection of coronary artery disease were 57.3%, 61.6% and 59.6% for mean IMT, 43.5%, 71.1% and 58.6% for maximum IMT, and 60.8%, 70.5% and 66.1% for number of plaques. Furthermore, the overall results (except maximum IMT) were 73.3%, 49.2% and 60.2%.
Conclusions: These results suggest that carotid ultrasonography is useful as a non-invasive and easy screening method for coronary artery disease. Furthermore, carotid ultrasonography will allow routine observations to follow the progression of coronary atherosclerosis.