Prevalence of thoracic aortic aneurysm in patients referred for no/low-charge coronary artery calcium scoring: Insights from the CLARIFY registry

Objective: Low-dose cardiac-gated chest CTs allow for simultaneous evaluation of coronary artery calcification and aortic size. We sought to evaluate the prevalence of thoracic aortic dilation (TAD) and thoracic aortic aneurysm (TAA) in a large cohort of patients undergoing coronary artery calcium (CAC) screening. Methods: We reviewed all patients from a large, prospective no-charge CAC screening program (CLARIFY, Clinicaltrials.gov NCT04075162) for whom measurements of the ascending aorta were available. TAD was defined as an ascending aortic diameter ≥4.0cm, while TAA was defined as ascending aortic diameter ≥ 4.5cm. We explored associations between patient characteristics, CAC, and the prevalence of TAD/TAA. Results: A total of 36,356 patients enrolled in the CLARIFY program underwent analysis for TAD/TAA. 3,130 patients (8.6%) had TAD and 237 (0.7%) had TAA. Patients with TAA were older (63±8 vs 59±10 years, p < 0.001), more likely to be male (87% vs 49%, p < 0.001), have higher BMI (32 vs 30 kg/m², p < 0.001), and 10-year atherosclerotic cardiovascular disease estimated risk (18% vs 12%, p < 0.001). Similar differences were observed for individuals with TAD compared to individuals without TAD with respect to age (63 vs 59 years, p < 0.001), percent male (76% vs 46%, p < 0.001), BMI (32 vs 30 kg/m², p < 0.001), and 10-year predicted risk (17% vs 11%, p < 0.001). CAC score was associated with prevalence of TAD (4.9% in those with CAC 0 to 16.5% in those with CAC≥400) and TAA (0.3% in those with CAC of 0 to 1.5% in those with CAC ≥400). Conclusion: In this large, prospective study of patients undergoing no-charge CAC screening, 8.6% had TAD (≥4.0cm) and 0.7% had TAA (≥4.5cm). Our results highlight a high yield of TAD/TAA diagnosis in this targeted cohort with cardiovascular risk factors and supports the role of no-charge CAC as a population-level strategy.