Observational Study of OCT in a Patients Undergoing FFR

Inclusion Criteria: 1. Age ≥ 18 years. 2. Patient provides signed written informed consent before any study-specific procedure. 3. De novo coronary artery disease in target vessel. 4. Single or multi vessel disease. For multi vessel disease up to two vessels and three lesions treated, with no more than two lesions per vessel. Vessel is defined as, left anterior descending, left circumflex, and right coronary arteries. Any branch within the vessel is considered part of the vessel. 5. Elective or ad hoc PCI, stable angina, acute coronary syndrome (unstable angina and NSTEMI). 6. Angiographically significant (\>50% visual estimation) stenosis present in at least one native coronary artery. 7. Mandatory use of FFR and OCT pre and post PCI. PCI strongly recommended in subjects with an FFR ≤ 0.80 in target vessel. Exclusion Criteria: 1. Subjects with STEMI, emergent PCI, or in cardiogenic shock. 2. Subjects with target left main lesion. 3. Subjects with restenosis or stent thrombosis in the target vessel. 4. Planned use of bare metal stent. 5. Known renal insufficiency (examples being but not limited to eGFR \< 60 ml/kg/m2, serum creatinine ≥ 2.5 mg/dL, or on dialysis). 6. Aorto-ostial lesion location within 3 mm of the aorta junction (both right and left). 7. Extreme angulation (\> 90°) or excessive tortuosity (\> two 45° angles) proximal to or within the target lesion. 8. Vessel(s) and lesion(s) not amenable for PCI, for example diffuse disease. 9. Any other medical condition that in the opinion of the investigator will interfere with patient safety or study results. 10. Currently participating in another clinical study that interferes with study results. 11. Pregnant or nursing subjects and those who plan pregnancy in the period up to 1 year following index procedure. 12. Life expectancy less than 1 year. 13. Potential for non-compliance to protocol requirements and follow-up. 14. Planned or prior heart transplantation or listed for heart transplant. 15. Any condition that precludes the subject from undergoing PCI, for example subjects with heparin induced thrombocytopenia, or contrast allergy.