Heartflow (AFFECTS)

Inclusion Criteria: * Age ≥ 18 years * Providing written informed consent * Subjects with abnormal SPECT myocardial perfusion imaging results who have been referred for clinically indicated ICA within 90-days of SPECT. * Ability to undergo cCTA Exclusion Criteria: * Acute coronary syndrome (ACS). * Prior, clinically documented, myocardial infarction (MI). * Prior coronary artery bypass grafting (CABG) * Prior coronary stenting * Evidence of ongoing or active clinical instability including unstable angina, intractable arrhythmia, cardiogenic shock, unstable BP, and severe CHF (NYHA class III or IV) or acute pulmonary edema * Contraindications for cCTA such as: 1. Presence of pacemaker or internal defibrillator leads such that coronary visualization is impaired 2. Chronic atrial fibrillation with uncontrolled ventricular response 3. Known anaphylactic allergy to iodinated contrast that cannot be pre-medicated 4. Pregnancy or unknown pregnancy status in women of childbearing age 5. Contraindication to acute beta blockade 6. Contraindication to acute sublingual nitrate administration 7. Prosthetic heart valve such that coronary visualization is impaired * Contraindications for FFRct such as: 1. Complex congenital heart disease other than anomalous coronary origins alone 2. Ventricular septal defect with known Qp/Qs \> 1.4 * Requiring an emergent procedure within 48 hours of presentation * Any active, serious, life-threatening disease with life expectancy less than 2 months * Inability to comply with study procedures * Current participation in any other clinical trial involving an investigational device, drug, or dictating care pathways at the time of enrollment