Personalized Risk Evaluation and Diagnosis (Using Corus CAD or ASGES) in the Coronary Tree

The purpose of the PREDICT study is to develop and validate a diagnostic blood ASGES (age, sex, gene expression score) or Corus CAD for atherosclerotic coronary artery disease (CAD). The Corus CAD (Age/Sex/Gene Expression score - ASGES) will use quantitative real-time PCR (RT-PCR) to quantify the expression of multiple genes from circulating peripheral blood cells to assess the presence of clinically significant CAD in a patient. This is a prospective, multi-center, observational study. Participation in the study does not alter clinical care. The only procedure required by the protocol is collection of a research blood sample. All other data collected will be in accordance with each participating institution's standard patient care. The study is divided into four sequential segments with unique subjects and goals: ASGES (Corus CAD) discovery (segment 1), ASGES (Corus CAD) development (segment 2), ASGES (Corus CAD) validation (segment 3), and additional ASGES (Corus CAD) testing (segment 4). The primary analysis will be performed during the third segment of the study using a subset of the enrolled subjects ("primary subjects"). Primary subjects will be defined by additional eligibility criteria beyond the general eligibility criteria required for enrollment in the overall study. The additional, post-enrollment eligibility criteria will be based on clinical and demographic factors that are found during the course of the study to affect the expression of genes used in the ASGES (Corus CAD). Such factors will be identified during gene discovery and algorithm development. The post-enrollment eligibility criteria will be defined prior to the beginning of the ASGES (Corus CAD) validation segment of the study. In addition, three substudies are planned and will enroll up to 1500 subjects. * The first substudy will include subjects undergoing cardiac CT angiography (CTA) and aims to determine how gene expression correlates with total coronary atheroma burden, as measured by CTA. * The second substudy examines sample handling and shipping conditions and does not affect the treatment of the subjects. * The third substudy will focus on additional algorithm development and validation in a non-diabetic female patient population.