Liquid Biopsy System Intracoronary Blood Sampling and Analysis to Characterise Disease Biomarkers in Patients With Coronary Disease

Inclusion Criteria: Stage 1 screening inclusion: 1. ≥18 years of age, have capacity and be willing to provide informed consent to participate 2. Clinical evidence of obstructive coronary artery disease and be scheduled for either: 1. Elective coronary angiography +/- proceed for stable angina OR 2. Elective PCI for stable angina with known bystander disease OR 3. Angiography +/- proceed for Troponin negative unstable angina Stage 2 screening inclusion: Suitable lesion identified meeting angiographic criteria for LBS deployment and Cardiologist comfortable to deploy OCT and LBS on study lesion before carrying out PCI on any lesion Exclusion Criteria: Stage 1 screening exclusion: 1. Myocardial Infarction within 30 days of procedure. 2. Chronic renal failure (eGFR\<30ml/min/1.73m2). 3. Contrast allergy. 4. Hypotension, shock or haemodynamic instability. 5. Ventricular arrhythmia. 6. Chronic Heart Failure (NYHA ≥ 3) or LVEF ≤ 30%. 7. Immunocompromised or receiving immunosuppressant therapy. 8. Any active disease that in the opinion of the investigator makes the subject unsuitable for the research procedure or subject life expectancy less than 1 year. 9. Active infection or sepsis (significant CRP elevation and/or requiring antibiotics). 10. Active systemic inflammatory condition. 11. Inability to receive anticoagulants or antiplatelets or uncorrected bleeding disorder or deranged platelet count. 12. Is pregnant. 13. Deemed high clinical risk or unsuitable for the procedure for any reason by the treating clinician. Stage 2 screening exclusion: 1. Target lesion is in the left main coronary artery. 2. Unsuitable coronary anatomy (vessel tortuosity \[\>45 degree bend\], moderate/ severe calcification angiographically, ostial disease). 3. Presence of thrombus in the target vessel. 4. Prior PCI or stent or graft in vessel identified for LBS sampling. 5. No clinical indication for either a PCI or a pressure wire assessment on any lesion.