Performance of a New REsting Pressure Index During Invasive Angiography Compared To Adenosine Hyperemic FFR

Inclusion Criteria: 1. Patients undergoing FFR assessment for standard clinical indications, according to individual operator decision. 2. Age ≥ 18 years. 3. Provided signed written informed consent for data collection the collection. 4. De novo coronary artery disease in target vessel. 5. Single or multiple vessel disease. 6. Patient eligible for elective or ad hoc PCI (or CABG), if revascularization is deemed indicated, in the setting of stable coronary artery disease or non-culprit lesions of non-ST elevation acute coronary syndromes (only in deferred procedures). 7. Stenosis deemed amenable for both evaluation with a pressure wire and for potential revascularization. Exclusion Criteria: 1. Subjects with restenosis in the target vessel. 2. Known severe renal insufficiency (examples being but not limited to eGFR \<30 ml/kg/min, serum creatinine ≥ 2.5 mg/dL or on dialysis). 3. Aorto-ostial lesion location within 3 mm of the aorta junction (both right and left). 4. Vessel(s) and lesion(s) not amenable for evaluation with a PressureWire™ and/or revascularization. 5. Tandem lesions 6. Moderate lesions in patients with multivessel disease in whom at least one lesion in another major epicardic vessel is severe (to minimize lesion interaction), unless the severe lesion is treated first (see above). 7. Left ventricular ejection fraction \<50% 8. Known severe left ventricular hypertrophy 9. Atrial fibrillation or any other significant arrhythmia (including an heart rate \<50/min on sinus rhythm) 10. Systolic blood pressure \<90 mmHg. 11. Any other medical condition that in the opinion of the investigator will interfere with patient safety or study results 12. Currently participating in another clinical study that interferes with study results. 13. Pregnant or nursing females 14. Planned or prior heart transplantation or listed for heart transplant. 15. Any condition that precludes the subject from undergoing PCI or any of the protocol mandated procedures, for example subjects with a prior history heparin induced thrombocytopenia, known intolerance to adenosine or with a contra-indication for dual anti-platelet therapy. 16. Patients with severe valvular disease 17. Patients with severe pulmonary disease 18. Culprit lesions in ACS patients are not to be included nor non-culprit lesions in patients with a recent STEMI undergoing staged procedures. 19. Patients with a CTO, regardless of the presence and the extent of angiographic collaterals from the target vessel.