OCTOCAB is a prospective, randomized (1:1), single-center trial. The purpose of this study is to determine whether intravascular optical coherence tomography (OCT) guided saphenous vein grafting in coronary artery bypass surgery will reduce the rate of early vein graft failure (VGF).

Within the first year of coronary artery bypass grafting (CABG) surgery, the saphenous vein grafts have a failure rate of 10 to 25%. Visual inspection of the vein graft conduit is the current standard in determining the quality of the vein segment. However, there may be intraluminal abnormalities that are undetectable via a visual inspection. OCT examination, using the ILUMIEN OPTIS NEXT OCT Imaging system, of endoscopically harvested saphenous vein conduits will indicate such pathology and enable the surgeon to assess the quality of the harvested vein at the intravascular level.

This study is designed to demonstrate the superiority of OCT-guided saphenous vein CABG in improving the rates of early VGF and the overall outcome of CABG.

The study will follow two randomization arms: OCT-guided saphenous vein CABG (interventional arm) vs. visual inspection-guided saphenous vein CABG (standard of care arm). The analysis of subjects will be with respect to their analyzed group.

Following enrollment, participants will be followed for up to 10 years. The primary endpoint is per graft incidence of vein graft failure. The assessment of the vein graft will be conducted via coronary CT angiogram (CCTA) at 12 months. In the case where the participant has unplanned angiogram due to clinical reasons, prior to the 12 months, the condition of the graft will be determined via the angiogram. Unless all target grafts have reached the endpoint prior to the 12 month time point, a CCTA will be required.

To achieve the power level of 85% at the significance level of 0.025, 760 patients is the anticipated sample size. Analysis will be conducted at the graft level with a Linear Mixed model to account for any potential patient effects.

Inclusion Criteria:

1. Subject must be at least 18 years of age.
2. Subject must have evidence of myocardial ischemia (e.g., stable angina, silent ischemia (ischemia in the absence of chest pain or other anginal equivalents), unstable angina, or acute myocardial infarction) suitable for elective CABG.
3. Subject must have undergone coronary angiography identifying at least one lesion that is clinically appropriate and suitable for saphenous vein bypass grafting.
4. Subject must provide written Informed Consent prior to any study related procedure.

Exclusion Criteria:

1. STEMI ≤24 hours from the onset of ischemic symptoms
2. Creatinine clearance ≤30 ml/min/1.73 m2 (as calculated by MDRD formula for estimated GFR) and not on dialysis.
3. Hypotension, shock or need for mechanical support or intravenous vasopressors at the time that the patient would be undergoing the index procedure.
4. CHF (Killip class >2 or NYHA class >3)
5. LVEF <30% by the most recent imaging test within 6 months prior to procedure. If no LVEF test result within 6 months is available, it must be assessed by echocardiography, multiple gated acquisition (MUGA), magnetic resonance imaging (MRI), ventriculography (LV gram) or other method.
6. Unstable ventricular arrhythmias
7. Concomitant multi-valve surgery or major aortic root surgery.
8. Planned non-cardiac surgery within 24 months after the index procedure
9. Prior CABG
10. Any planned PCI within any target vessel(s) within 24 months.
11. Subject has known hypersensitivity or contraindication to any of the study drugs (including aspirin, all P2Y12 inhibitors).
12. Subject has received a heart transplant.
13. Subject is receiving immunosuppressant therapy or has known immunosuppressive or severe autoimmune disease that requires chronic immunosuppressive therapy (e.g., human immunodeficiency virus, systemic lupus erythematosus, etc.).
14. Subject has previously received or is scheduled to receive radiotherapy to a coronary artery (vascular brachytherapy), or the chest/mediastinum.
15. Subject has a platelet count <100,000 cells/mm3 or >700,000 cells/mm3.
16. Subject has a documented or suspected hepatic disorder as defined as cirrhosis or Child-Pugh ≥ Class B.
17. Subject has a history of bleeding diathesis or coagulopathy.
18. Subject has life expectancy <2 years for any non-cardiac cause.
19. Pregnant or nursing subjects and those who plan pregnancy in the period up to 2 years following index procedure. Female subjects of child-bearing potential must have a negative pregnancy test done within 7 days prior to the index procedure per site standard test.
20. Presence of other anatomic or comorbid conditions, or other medical, social, or psychological conditions that, in the investigator's opinion, could limit the subject's ability to participate in the clinical investigation or to comply with follow-up requirements, or impact the scientific soundness of the clinical investigation results.

Conduit exclusion criteria

1. Severe conduit tortuosity of venous conduit (e.g., with varicosities) such that it is unlikely that the OCT catheter can be delivered without vascular damage.

For follow-up visits, in person and via phone, the provider will be blinded. Physicians analyzing Coronary CT Angiograms (CCTA) will be blinded to the randomization arm.