RecruitingProcedureEvaluation of Patients With Non-obstructive Coronary ArteriesPatients with angina and non-obstructive CAD are common within clinical practice, but remain a challenge with regard to diagnosis and treatment. When these patients undergo a comprehensive evaluation at the time of invasive coronary angiography, occult coronary abnormalities are frequently found. We hope to learn the overall prevalence and presentation of these occult coronary abnormalities and its long term outcome in this patient population.