Finding the Invasive Haemodynamic Threshold for Symptom Relief in Stable Angina

Inclusion Criteria: * Eligibility for percutaneous coronary intervention (PCI) due to angina or angina-equivalent symptoms on exertion * Anatomical evidence of significant single-vessel coronary stenosis defined by either: * ≥70% stenosis on invasive coronary angiography (ICA) * Severe stenosis on CT coronary angiography (CTCA) * Physiological evidence of ischaemia with a positive test on at least one of the following: * Stress echocardiography * Cardiac magnetic resonance perfusion * Myocardial perfusion scintigraphy * Invasive metrics of coronary physiology Exclusion Criteria: * Age \<18 years * Recent acute coronary syndrome * Previous coronary artery by-pass graft * Significant left main stem disease * Multivessel disease (defined as \>50% angiographic stenosis in other vessels) * Chronic total occlusion in the target artery * Moderate to severe valvular disease * Moderate to severe left ventricular impairment * Chronotropic incompetence with a pacemaker * Contraindication to PCI or a drug-eluting stents * Contraindication to antiplatelet therapy * Contraindication to adenosine * Moderate to severe respiratory disease * Physical inability to exercise * Pregnant * Inability to consent