Left atrial axial area index, epicardial fat volume, and thoracic aortic calcification from non-contrast enhanced cardiac computed tomography (CT) assessments improved prediction of cardiovascular events over coronary artery calcium (CAC) scores and established risk factors.
Amir A. Mahabadi, MD, of the West-German Heart Center at the University of Duisburg-Essen in Germany, and colleagues evaluated non-coronary measures from cardiac CT in 3060 individuals (average age: 59 ± 8 years; 46% male) to evaluate the prognostic value of the imaging technique. Their findings were published in JACC: Cardiovascular Imaging.
Individuals from the Heinz Nixdorf Recall study without known cardiovascular disease underwent non-contrast cardiac CT for CAC-score quantification. From the CT, researchers assessed left ventricular and left atrial axial area index, epicardial fat volume, ascending and descending aortic diameters, and aortic valve, mitral ring, and thoracic aortic calcification.
The study end points were considered incident coronary events, stroke, or cardiovascular death.
A total of 241 participants (6.6%) experienced a cardiovascular event during a follow-up period of 9.9 ± 2.6 years. When researchers conducted a multivariable Cox regression analysis that included the Framingham Risk score, CAC score, and CT-parameters, left atrial index (hazard ratio [HR]: 1.18; 95% confidence interval [CI]: 1.02-1.37; P=.023) and epicardial fat volume (HR: 1.18; 95% CI: 1.02-1.34; P=.023) were significantly associated with incident events.
Presence of thoracic aortic calcification revealed an elevated event rate (HR: 1.14; 95% CI: 0.83-1.57; P=.41), but all other CT-dervived parameters showed no significant association with incident cardiovascular events.
Together, left atrial index, epicardial fat volume, and presence of thoracic aortic calcification improved the prediction of cardiovascular events over Framingham Risk Score and CAC in receive operating characteristics analysis (area under the curve: 0.749-0.764; P=.011). The combination also led to a significant net reclassification improvement of 38% (95% CI: 25.1%–50.8%).
“Once cardiac CT-imaging is performed for quantification of coronary plaque burden, information on other cardiac and thoracic structures is readily available without additional radiation exposure and contrast media application,” the authors wrote.
“Our results encourage the assessment of non-coronary measures as they improve prediction of hard cardiovascular events and allow for risk stratification in the general population when combined and therefore increase the prognostic value that may be drawn from this imaging modality.”
Mahabadi AA, Lehmann N, Mohlenkamp S, et al. Non-coronary measures enhance the predictive value of cardiac computed tomography above traditional risk factors and coronary artery calcification in the general population. JACC Cardiovasc Imag. 2016. doi: 10.1016/j.jcmg.2015.12.024.