Clinical Research Directory

Inclusion Criteria: * Clinical presentation of chronic ischemic heart dis- ease (IHD), requiring coronary angiography for the diagnosis; * Absence of obstructive coronary artery disease (CAD) at coronary angiography; * Age \> 18 years. * Ability to provide a valid informed consent to the study procedure at the time of baseline evaluation; Exclusion Criteria: Clinical presentation of acute coronary syndrome (ACS) or cardiogenic shock; * Presence of obstructive CAD with at least 1 significant coronary artery stenosis, defined as diameterstenosis \>50% and FFR ≤0.80 (or iFR/RFR ≤0.89); * Previous coronary artery bypass grafting (CABG); * Left ventricular systolic dysfunction, defined as ejection fraction (EF) \<40%; * Severe valvular heart disease; * Pregnant or breastfeeding women * Known hypersensitivity or contraindication to any of the drugs used for coronary physiology testing (adenosine, nitrates, acetylcholine) * Inability or unwillingness to provide a valid in- formed consent to the study procedure at the time of baseline evaluation.