Prevalence of non-calcified coronary plaque on 64-slice computed tomography in asymptomatic patients with zero and low coronary artery calcium.

Objectives: To study the prevalence of noncalcified plaque in asymptomatic low-risk patients with no or mild coronary artery calcium (CAC).

Methods: From 502 patients with coronary risk factors who underwent 64-slice computed tomography, 224 asymptomatic patients were identified with no CAC (n=117) or mild CAC (n=107; defined as patients with Agatston scores from 1 to 100).

Results: Patients with no CAC were younger and had diabetes less often. Medications and laboratory data were not significantly different between the two groups. The prevalence of noncalcified plaque was 11.1% in patients with no CAC and 23.4% in the mild CAC group (P=0.0142). Multiple plaques were detected in 2.6% of the group with no CAC and 3.7% of the group with mild CAC (P=0.5934). Significant coronary artery stenosis was found in one patient in the group with no CAC (0.9%) and three patients in the group with mild CAC (2.8%, P=0.3506).

Conclusions: Significant percentages of noncalcified plaque were found in asymptomatic low-risk patients with no or mild coronary calcium.