This study is a non-randomized prospective cohort study that will define the rate of index atherosclerotic plaque development in adults with a prior CAC score of 0 given prior CAC zero > 5 years previous. Study personnel will abstract CAC and coronary computed tomography angiography (CCTA) results on or prior to 31 December 2010 in a single, high-volume military medical center. All patients with CAC scores of zero, irrespective of whether or not this zero CAC was calculated in the presence of a CCTA with non-calcified plaque, will be offered inclusion in the study cohort. Patients will be contacted via telephone and offered study participation. Patients who sign written informed consent will be interviewed to abstract current medical history, medications, exercise practices, and social history. Cardiovascular risk factors of interest will be hypertension, hyperlipidemia, diabetes mellitus, and family history. Patients will then undergo blood draw (complete metabolic panel, complete blood count, lipid panel, serum insulin, high-sensitivity C-reactive protein (CRP), hemoglobin A1c, and thyroid function testing) to screen for undergoing cardiovascular risk factors and to be used as potential risk markers. Additionally, whole blood and serum will be obtained for future investigation to determine new markers of coronary artery disease (CAD) progression and genetic polymorphisms that may predict CAD progression. Patients will also undergo EndoPat testing utilizing an EndoPAT 2000® (digital pulse amplitude tonometry) to assess for endothelial dysfunction. Finally, patients will undergo repeat coronary artery calcium scoring based on standard laboratory protocols based on heart rate and body mass index.
This study is a non-randomized prospective cohort study that will define the rate of index atherosclerotic plaque development in adults with a prior coronary artery calcium (CAC) score of 0 given prior CAC zero > 5 years previous. Ancillary testing of serum, whole blood, and endothelial dysfunction will be performed to investigate any detectable systemic processes that predict CAC development.