This group will have patients who have undergone clinically-indicated CT coronary angiography (CT-A) and who have no plaque and an Agatston score of "0". They will then undergo a myocardial contrast echocardiography study during vasodilator stress to subdivide risk further into "No atherosclerosis/endothelial function normal" and "No atherosclerosis/endothelial function abnormal". Blood will then be collected for metabolomics, lipidomic and whole genome sequencing.

This group will have patients who have undergone clinically-indicated CT coronary angiography (CT-A) and who have non-critical plaque (<50% diameter) and at least 1 high risk feature according to the ROMICAT indices. They will then undergo a myocardial contrast echocardiography study during vasodilator stress to subdivide risk further into "atherosclerosis/endothelial function normal" and "atherosclerosis/endothelial function abnormal". Blood will then be collected for metabolomics, lipidomic and whole genome sequencing.

Myocardial contrast echocardiography will be performed to further stratify risk as described in the cohort section.

In this study, "outcomes" are essentially pre-determined by the patient population according to imaging stratification. Omic patterns of will be assessed by advanced informatics modeling (Random Forest analysis) to determine metabolomic, genomic, and lipidomic patterns that vary according to incremental risk scaling from lowest (no plaque and normal endothelial function) to highest (+ plaque and endothelial dysfunction).