Inclusion Criteria:  Written informed consent available. Age ≥ 18 years. Patient eligible for invasive physiological assessment with adenosine and / or acetylcholine.  Exclusion Criteria:  Hemodynamic instability. Anticipated technical issues for physiology wire measurements. Culprit vessel of acute coronary syndrome Contraindications for adenosine administration. Contraindications for acetylcholine test. Reduced life expectancy (less than 1 year).