Study of Lesion-Specific Invasive Haemodynamic Angina Thresholds

ORBITA-SOLAR is an invasive physiological cardiac catheterisation study that aims to determine whether different coronary stenoses have different angina thresholds. The angina threshold is defined as the amount of coronary flow reduction required to reproduce symptoms. Sixty patients with symptoms of stable angina and 2 coronary artery stenoses amenable to percutaneous coronary intervention (PCI) will be recruited. This study will use intra-coronary balloon inflation during supine exercise to measure the fractional flow reserve (FFR) and non-hyperemic pressure ratio (NHPR) that corresponds to angina onset.

Inclusion Criteria: 1. Eligibility for PCI due to angina or angina-equivalent symptoms on exertion 2. 2 severe epicardial stenoses in a major coronary artery, defined as: 1. ≥70% stenosis in a coronary artery with ≥2.5mm diameter, on invasive coronary angiography (ICA) 2. Severe stenosis in a vessel with ≥2.5mm diameter, on CTCA 3. Evidence of ischaemia on an invasive or non-invasive test, including: 1. Physiological test during invasive coronary angiography (ICA) 2. Dobutamine stress echocardiography (DSE) 3. Stress perfusion cardiac magnetic resonance (CMR) 4. Myocardial perfusion scintigraphy (MPS) 5. Fractional flow reserve computed-tomography (FFR-CT) Exclusion Criteria: 1. Age \