Frequency and extent of coronary atherosclerotic plaques in patients with a coronary artery calcium score of zero: assessment with CT angiography.

PURPOSE We aimed to evaluate the frequency and extent of coronary atherosclerotic plaques in patients with a coronary artery calcium (CAC) score of zero and establish the demographic characteristics and the cardiovascular risk factors that affect the formation of atheromatous plaques. MATERIALS AND METHODS Coronary computed tomography (CT) angiography was performed in 288 cases with a CAC score of zero. The plaques that were detected using coronary CT angiography were categorized into two groups: nonsignificant (<50%) and significant (≥50%). Based on the coronary CT angiography results, the patients who had plaque and those who did not have plaque were compared in terms of the demographic characteristics and the presence of cardiovascular risk factors. RESULTS Noncalcified plaques were detected in 50 cases (17.4%) on CT angiography, of which six cases (2.1%) had significant stenosis. The plaques were localized most frequently (38.2%) in the proximal left anterior descending artery. When all the plaques considered 50% of the plaques were localized in the proximal segments, 42.7% were in the mid-segments, and 7.3% were in the distal segments. Hypertension was a significant risk factor for coronary artery disease in both genders, and smoking was a significant risk factor in females. Additionally, diabetes mellitus was a borderline significant risk factor in both genders. CONCLUSION In patients with a CAC score of zero, the frequency of noncalcified plaques is too high to be ignored. The distribution of these plaques in the coronary artery is similar to calcified plaque localizations. Patients who have a CAC score of zero and cardiovascular risk factors need to be evaluated with additional tests for the detection of noncalcified plaques.