SPARC, Including Its Pilot CT Angiographic Study, is a Prospective, Open-label, Multicenter, Sequentially Sampled, Observational Registry to Define the Clinical Value of Stress Perfusion (Stress SPECT, Stress PET), Noninvasive Angiography (CTA) and Combined Perfusion-anatomy (PET/CT) Studies in Patients With Known or Suspected CAD With Respect to Post-test Resource Utilization and Prediction of Cardiac Death and Non-fatal Myocardial Infarction

Three main clinical outcomes will be assessed:

1. Post-test resource utilization as assessed by referral rate to catheterization within 90-days of the index study;
2. Incremental prognostic value and risk stratification for predicting cardiac death and myocardial infarction;
3. Cost-effectiveness

To this end, SPARC is organized with two distinct specific objectives with important differences in patient population and endpoints.

Specific Aim 1: To evaluate the impact of stress perfusion imaging with SPECT or PET, CT Angiography, and hybrid PET-CT on post-test resource utilization.

The primary endpoint of specific aim 1 is to compare the impact of combined myocardial perfusion-coronary anatomy data to that of perfusion only [stress SPECT, stress cardiac PET (without CTA)] and anatomy only (CTA alone) on post-test resource utilization, as measured by referral to cardiac catheterization within 90 days of index noninvasive testing, in patients without CAD.

Secondary endpoints:

1. to compare the diagnostic accuracy for detection of epicardial CAD of stress PET and hybrid PET-CT, stress SPECT, and CTA, as defined by coronary angiography;
2. to compare the referral rate to revascularization within 90 days of cardiac catheterization.

Specific Aim 2: To compare the incremental prognostic value and risk stratification of stress perfusion imaging with SPECT or PET, CT coronary angiography, and combined perfusion-anatomy imaging approaches.

The primary endpoint of specific aim 2 is to compare the incremental value of stress perfusion only (stress PET and stress SPECT), coronary anatomy only (CTA data), and combined perfusion-anatomy studies (PET+CTA and SPECT+CTA) over clinical, historical and stress test data for the prediction of cardiac death and nonfatal myocardial infarction.

Secondary endpoints:

1. to compare the incremental value of these noninvasive imaging approaches over clinical, historical and stress test data for the prediction of a composite endpoint including cardiac death, nonfatal myocardial infarction, late (>6 month from index study) referral to revascularization, or late (>6 month from index study) hospitalization for chest pain or heart failure;
2. to compare the incremental value of these noninvasive imaging approaches over clinical, historical and stress test data for the prediction of all cause mortality. In addition, the ability of these modalities -together and separately- to risk stratify patients is a primary goal of specific aim 2.