The Philips Angio-iFR medical software device is intended to provide information on the functional significance of a coronary artery lesion to provide guidance on diagnostic decisions similar to that obtained through invasive measures of iFR and FFR. The software application uses the vessel geometry obtained from a coronary angiographic image together with a lumped parameter physiological model to provide the associated iFR and FFR estimates.

This study is intended to demonstrate the diagnostic performance of the image-derived physiology model using the invasive physiological measures as the reference standard.

Specific objectives include the following:

i) Demonstrate the sensitivity and specificity of image-derived iFR and FFR results for identifying functionally significant lesions as determined by the corresponding invasive measures; ii) Demonstrate the diagnostic agreement of image-derived iFR and FFR estimates with the corresponding invasive measures; iii) Demonstrate the diagnostic performance of image derived physiology estimate (iFR/FFR) is superior to visual angiographic assessment for the identification of functionally significant stenoses as determined by the corresponding invasive physiology measures; iv) Demonstrate reproducibility of the image-derived estimate for a given operator and across multiple operators for a given lesion.

Inclusion Criteria:

1. ≥18 years old
2. At least 1 de-novo lesion in 1 or more major epicardial vessels of 40-90% angiographic stenosis with a reference vessel size ≥2.5mm in the diseased segment by visual estimate
3. Able and willing to provide informed consent

Exclusion Criteria:

1. Presenting with an acute coronary syndrome (ACS), or documented ACS within 4 weeks prior to the scheduled index procedure
2. Cardiogenic shock (sustained (>10 min) systolic blood pressure <90 mmHg in absence of inotropic support or the presence of an intra-aortic balloon pump)
3. Presence of cardiac arrhythmias (e.g., atrial fibrillation, AV-block)
4. Prior cardiac surgery or implant, including CABG, heart transplant, surgical heart valve replacement or repair, TAVI/TAVR, presence of an ICD or pacemaker
5. Target vessel supplied by a left main coronary artery demonstrating any disease present (isolated or non-isolated)
6. Target vessel supplied by right coronary artery demonstrating any ostial disease (located immediately at the origin of the coronary vessels from the aorta)
7. Target vessel with Chronic Total Occlusion (CTO) in the ipsilateral territory or target vessel with an untreated CTO in the contralateral territory. Note: if a CTO existing in the contralateral territory is successfully opened, the target vessel in the contralateral territory can be included following CTO treatment.
8. Target vessel with severe tortuosity (≥1 bends of 90° or more, or ≥3 or more bends of 45°- 90° proximal to the diseased segment)
9. Target vessel with heavy calcification (multiple persisting opacifications of the coronary wall visible in more than one projection surrounding the complete lumen of the coronary artery at the site of the lesion.)
10. Target vessel with TIMI flow grade 1 or 0
11. Target vessel with severe diffuse disease (more than 75% of the length of the segment having a vessel diameter of 2mm, irrespective of the presence or absence of a lesion)
12. Target lesion is at a bifurcation/trifurcation
13. Target arteries supplying akinetic or severely hypokinetic territories if already known based on prior imaging
14. Target vessel is supplied by major collaterals
15. Target stenosis associated with myocardial bridge
16. Any vascular abnormality precluding optimal contrast opacification (e,g, thrombus, ulceration)
17. Severe aortic or mitral valve disease
18. Known ejection fraction ≤30%
19. Known severe renal insufficiency (eGFR<30ml/min/1.72m2)
20. Any fluoroscopic interference that renders the wire position unclear
21. Contraindication for adenosine or other hyperemic agent (e.g., caffeine ingestion ≤18 hours, COPD, hypotension, AV block)
22. Known pregnancy or planning to become pregnant
23. Participating in another interventional investigational study

Patients referred for cardiac catheterization for diagnostic and/or treatment purposes will undergo a screening angiogram to assess eligibility. Eligible patients will be those with at least one major epicardial vessel having a lesion of 40-90% diameter stenosis per visual assessment of angiogram.