Prevalence of noncalcified coronary plaques by 64-slice computed tomography in patients with an intermediate risk for significant coronary artery disease.

OBJECTIVES

In this prospective study, we investigated the prevalence and characteristics of clearly discernible noncalcified coronary plaques in a patient population with suspected significant coronary artery disease (CAD) by using 64-slice computed tomography (CT).

BACKGROUND

The assessment of noncalcified coronary plaques by noninvasive strategies may be important to improve cardiovascular risk stratification.

METHODS

To rule out significant stenosis, high-resolution 64-slice coronary CT (0.6-mm collimation, 330-ms gantry rotation time) was performed in 161 consecutive patients with an intermediate risk for having CAD. Computed tomography data sets were evaluated for presence of coronary calcifications, noncalcified plaques, and/or lumen narrowing.

RESULTS

Noncalcified coronary plaques were detected in 48 (29.8%) of 161 enrolled patients. Although noncalcified plaques together with coronary calcifications were present in 38 of 161 (23.6%) patients, the prevalence of noncalcified plaques as the only manifestation of CAD was 6.2% (10 of 161 patients). Patients with noncalcified plaques were characterized by significantly higher total cholesterol, low-density lipoprotein, and C-reactive protein levels as well as a trend for more diabetes mellitus. The majority of noncalcified plaques resulted in lumen narrowing of <50%. Of the remaining 113 patients, CAD and coronary calcifications were ruled out in 53 of 161 (32.9%) patients, whereas 60 of 161 (37.3%) patients presented with calcifications in the absence of noncalcified plaque.

CONCLUSIONS

With the use of 64-slice CT, clearly discernible noncalcified atherosclerotic coronary plaques can be detected in a large group of patients with an intermediate risk for having CAD. The assessment of these plaques by CT angiography may allow for improved cardiovascular risk stratification.