Preliminary Observations on Discordance Between Coronary Artery Calcium Score of Zero and Coronary Computed Tomography Angiography Findings in Asymptomatic Adults

Abstract

Background: Coronary artery calcium (CAC) scoring is widely used to screen for coronary artery disease (CAD) in asymptomatic individuals. However, it detects calcified plaques and may miss non-calcified or soft plaques. This study compared the diagnostic accuracy of CAC scoring with coronary computed tomography angiography (CCTA) for detecting CAD in asymptomatic individuals with risk factors.

Methods: Eighteen asymptomatic adults with a CAC score of 0 underwent CCTA to evaluate for subclinical CAD. Clinical, biochemical, and lifestyle risk factors were assessed. Diagnostic agreement between CAC and CCTA was analyzed using the Wilcoxon signed rank test.

Results: The cohort had a mean age of 51.4 ± 10.6 years, 88.8% were male, and mean body mass index (BMI) was 27.7 ± 3.6 kg/m². Smoking (70.5%) and family history of CAD (56.25%) were prevalent. Biochemical analyses showed preserved renal function and non-diabetic glycemic profiles. Despite the absence of calcification on CAC, CCTA revealed CAD in 72.2% (13/18) of participants, detecting non-calcified plaques missed by CAC scoring. Elevated cardiac and inflammatory markers, including high-sensitivity cardiac troponin T, apolipoprotein B (apoB), and lipoprotein(a) (Lp(a)), were observed in those with positive CCTA findings. The Wilcoxon signed rank test indicated a significant difference between the modalities (Z = -3.606, P < 0.001).

Conclusions: CCTA detected non-calcified atherosclerosis missed by CAC and demonstrated superior sensitivity for early CAD detection in asymptomatic individuals.