Background: Coronary artery aneurysms (CAA) put patients (pts) at risk for thrombosis and myocardial infarction. Clinical guidelines recommend systemic anticoagulation for giant CAA, diameter ≥ 8mm. Pt-specific modeling and computer simulations in KD pts suggest that hemodynamic data can predict regions with increased risk of thrombus formation and may be superior to simple assessment of the geometry of the aneurysm. Specifically, regions with high Particle Residence Time gradients (PRTg) have correlated with regions of thrombus formation.
Methods: Transluminal Attenuation Gradient (TAG) is determined from the change in radiological attenuation on CT angiography (CTA) images in Hounsfield units per vessel length. TAG analysis has been used for characterizing coronary artery stenoses; however this approach has not been used for CAA. We analyzed the correlation between TAG and PRTg in KD pts with CAA and evaluated TAG for prediction of thrombotic risk.
Results: Pt-specific anatomic models for flow simulations were constructed from CTA image data from 6 KD pts with CAA and one normal control. TAG was calculated for all aneurysmal vessels and one control vessel. TAG values for the CAA were markedly lower than for the non-aneurysmal vessel (mean -23.76 vs. -2.21). In addition, TAG values were compared to PRTg and other hemodynamic data obtained for each pt.
Conclusion: TAG analysis is a new technique that can be applied to pt data obtained non-invasively through CTA. Thrombotic risk stratification for CAA and decisions about whether to start systemic anticoagulation may be improved by incorporating TAG and should be evaluated in future prospective studies.