The purpose of this study is to compare different methods of collecting the amount of radiation exposure patients receive in a clinical study. As part of the PROMISE study, the Duke Clinical Research Institute Outcomes and Follow-up Group will be contacting patients every six months to ask if they had any heart procedures or testing. This information will be used to estimate the amount of radiation that they may have received from heart testing being studied in this study, PROMISE-SAFER. Patients will be asked to collect information about each heart testing they receive during the time that they are enrolled in the PROMISE study. At the conclusion of the study, we will be able to determine which method was most accurate in collecting the amount of radiation exposure for this clinical study. Through this study we hope to develop an improved methodology to estimate cumulative radiation exposure from cardiac imaging. Comprehensive measurement of cumulative radiation exposure to patients may be critically important to minimize potential harm in future studies and in clinical practice.

Inclusion Criteria: All patients who meet inclusion criteria and enroll in the parent PROMISE study will be eligible to participate in PROMISE-SAFER.

1. New or worsening chest pain syndrome or equivalent symptoms suspicious for clinically significant coronary artery disease

2. No prior evaluation for this episode of symptoms

3. Planned non-invasive testing for evaluation of possible coronary artery disease

4. Men age > 55 and women age ≥65 years

5. If age in men 45 - 54 or women 50 - 64 years, then must have increased probability of CAD due to EITHER:

   A. Diabetes Mellitus (DM) requiring medical treatment OR Peripheral Arterial Disease (PAD) defined as documented >50% peripheral arterial stenosis treated medically or invasively OR Cerebrovascular disease (stroke, documented > 50% carotid stenosis treated medically or invasively)

   OR

   B. At least one of the following cardiovascular risk factors:

   • Ongoing tobacco use
   • Hypertension
   • Abnormal ankle-brachial index defined as less than <0.9
   • Dyslipidemia

6. Serum creatinine < 1.5 mg/dL within the past 90 days

7. Negative urine/serum pregnancy test for female subjects of child-bearing potential and not breast-feeding

Exclusion Criteria:

1. Diagnosed or suspected acute coronary syndrome requiring hospitalization or urgent or emergent testing; Elevated troponin or creatinine kinase-MB

2. Hemodynamically or clinically unstable condition (systolic blood pressure < 90 mmHg, atrial or ventricular arrhythmias, or persistent resting chest pain felt to be ischemic despite adequate therapy)

3. Known coronary artery disease with prior myocardial infarction, percutaneous coronary intervention, coronary artery bypass grafting or any angiographic evidence of coronary artery disease ≥50% lesion in a major epicardial vessel.

4. Any invasive coronary angiography or non-invasive anatomic or functional cardiovascular test for detection of coronary artery disease, including coronary computed tomographic angiography and exercise electrocardiogram, within the previous twelve (12) months.

5. Known significant congenital, valvular (> moderate) or cardiomyopathic process (hypertrophic cardiomyopathy or reduced systolic left ventricular function (left ventricular ejection fraction ≤ 40%)) which could explain cardiac symptoms.

6. Contraindication to undergoing a coronary computed tomographic angiography, including but not limited to:

   a. Pregnancy or breastfeeding

7. Life expectancy < 2 years

8. Unable to provide written informed consent or participate in long-term follow-up

PROMISE study patients