Prognostic Value of CT dynamIc Myocardial Perfusion in Patients With Obstructive Coronary Artery Stenosis

Inclusion Criteria: 1. age ≥18 years. 2. stable chest pain with obstructive coronary stenosis (50-90%) assessed by CTA. Exclusion Criteria: * (1) Diagnosed or suspected acute coronary syndrome (ACS) requiring hospitalization or urgent or emergent testing; Elevated troponin or creatine kinase-myocardial band (CK-MB). (2) Hemodynamically or clinically unstable condition systolic blood pressure (BP) \< 90 mmHg, atrial or ventricular arrhythmias, or persistent resting chest pain felt to be ischemic despite adequate therapy. (3) Known CAD with prior Myocardial infarction (MI), percutaneous coronary intervention (PCI), coronary artery bypass graft (CABG). (4) Known significant congenital, valvular (\> moderate) or cardiomyopathic process (hypertrophic cardiomyopathy or reduced systolic left ventricular function (LVEF) ≤ 40%)) which could explain cardiac symptoms. (5) Contraindication to undergoing CTA, including but not limited to: a. Allergy to iodinated contrast agent, b. Unable to receive beta blockers, c. creatinine ≥1.7 mg/dl or GFR≤30 ml/min , d. Pregnancy. (6) Contraindication to ATP, including but not limited to: a. II or III atrioventricular block, b. bronchial asthma, c. hypotension (SBP\<90mmHg), d. bronchial stenosis or bronchospasm, e. acute myocardial infarction, f. left main stenosis, g. unstable angina, h. allergy to aminophylline. (7) Life expectancy \< 2 years. (8) Unable to provide written informed consent or participate in long-term follow-up.