Agatston score of the descending aorta is independently associated with coronary events in a low-risk population

Objectives: A standard coronary artery calcium scan includes part of the aorta. This additional information is often not included in routine analyses. We aimed to determine the feasibility of assessing the Agatston score of the descending aorta calcification (DAC) on standard coronary calcium scans and the association of this score with coronary events in a low-risk study population.

Methods: Between January 2008 and March 2011, 390 consecutive patients who were referred for cardiac CT as part of work-up for pulmonary vein isolation (n=115) or assessment of presence of coronary artery disease (n=275) were included. At baseline, all patients were free of a history of cardiovascular disease. Two independent observers determined the Agatston score of the ascending aorta and descending aorta.

Results: A total of 16 patients (4.1%) developed coronary events (acute coronary syndrome (n=6) and symptomatic significant coronary artery disease requiring treatment (n=10)) during a follow-up of 67±12 months, with more events in patients with calcifications in the descending aorta than in those without (8.4% vs 3.7 %; p=0.08). Multivariable Cox regression, corrected for Framingham Risk Score (FRS) and coronary Agatston score (CAC), revealed that DAC was independently associated with coronary events (per 100 units; HR: 1.06, 95% CI 1.02 to 1.09; p=0.001). DAC furthermore increased the identification of patients that will experience a coronary event (area under the curve: 0.68 for FRS only, 0.75 for FRS+CAC and 0.78 for FRS+CAC+DAC).

Conclusions: The Agatston score of the descending aorta could be included in the standard analysis of cardiac CT scans of low-risk patients since it holds valuable information for the prediction of coronary events.