Prevalence of Coronary Artery Disease in Symptomatic Patients with Zero CAC Score by Age Group

This cross-sectional study examined 5,514 symptomatic patients referred for CCTA who were found to have a CAC score of zero, characterizing the prevalence of non-calcified plaque and obstructive coronary artery disease by age group.

Among 5,514 patients with CACS=0, 25.3% had identifiable coronary plaque (non-calcified, invisible to calcium scoring), and 9.3% had obstructive CAD (≥50% stenosis) by CCTA. Prevalence of both non-calcified plaque and obstructive CAD increased significantly with age: obstructive CAD with CACS=0 was uncommon below age 50 but reached clinically significant prevalence in older patients.

This study directly addresses the critical question about the CAC=0 “warranty period.” In asymptomatic individuals, CACS=0 is associated with very low event rates over follow-up (Valenti et al., 2015). But this study examines symptomatic patients — those referred for evaluation specifically because of chest pain, dyspnea, or other cardiac symptoms — in whom CACS=0 does not exclude significant non-calcified plaque or even obstructive CAD.

The distinction between symptomatic and asymptomatic contexts is fundamental. In asymptomatic primary prevention patients, CACS=0 appropriately supports deferral of further testing and therapy. In symptomatic patients where CAD is clinically suspected, CACS=0 does not exclude CAD requiring CCTA for definitive assessment.

We rate the evidence moderate. A large cross-sectional study demonstrating that 9.3% of symptomatic patients with zero CAC have obstructive CAD — important evidence clarifying that CACS=0 does not exclude significant CAD in symptomatic patients, who require CCTA rather than calcium scoring alone.