Influence of Age on the Diagnostic Value of Coronary Artery Calcium Score for Ruling Out Obstructive Coronary Disease in Symptomatic Patients.

Concerns have been raised about the added diagnostic value of coronary artery calcium score (CACS) of 0 for reducing the likelihood of obstructive coronary artery disease (CAD) in younger patients. Our study aimed to assess the influence of age on the value of CAC = 0 in symptomatic patients who underwent coronary computed tomography angiography (CCTA). We conducted a 2-center retrospective study assessing symptomatic patients with suspected CAD who underwent CACS and CCTA. Pretest probability was calculated according to the Juarez-Orozco method and obstructive CAD was defined as ≥50% luminal stenosis. The diagnostic likelihood ratios and negative predictive values were used to assess the diagnostic value of a CACS of 0 to rule out obstructive CAD. A total of 2,043 patients (mean age 60 ± 11 years, 60% women, 48.5% CACS of 0) were analyzed. The pretest probability of obstructive CAD increased with age, whereas the proportion of patients with a CACS of 0 decreased with age. The added diagnostic value of a CACS of 0 was lower in younger patients (negative likelihood ratios ranging from 0.36 for <50 years to 0.10 for ≥70 years). However, the prevalence of obstructive CAD in patients with a CACS of 0 was low in all age groups. In a cohort of symptomatic patients who underwent CCTA for suspected CAD, the added diagnostic value of a CACS of 0 decreases significantly at younger ages. However, it is offset by their lower pretest probabilities, yielding high negative predictive values independently of age.