Multivessel Balloon Occlusion to Investigate Obstructive Coronary Artery Disease and aNgina

Inclusion Criteria: * Eligibility for PCI due to angina * Anatomical evidence of significant multi-vessel coronary stenosis defined by either: 1. ≥70% stenosis in two or more coronary arteries of ≥2.5mm visual diameter stenosis, on invasive coronary angiography (ICA) 2. Severe stenosis in ≥2 coronary arteries of ≥ 2.5mm visual diameter stenosis, on CTCA * Physiological evidence of ischaemia with a positive test corresponding to the coronary arteries to be stented, on at least one of the following: * dobutamine stress echocardiogram * cardiac MRI * myocardial perfusion study * invasive metrics of coronary physiology Exclusion Criteria: * Recent acute coronary syndrome * Previous coronary artery by-pass graft surgery (CABG) * Significant left main stem disease * Chronic total occlusion in the target artery(s) * Moderate to severe valvular disease * Moderate to severe left ventricular impairment * Contraindication to PCI or a drug-eluting stents * Contraindication to antiplatelet therapy * Contraindication to adenosine * Pregnant * Inability to consent