Introduction

Ischaemic heart disease is a leading cause of death worldwide and stable angina is the commonest symptomatic manifestation affecting 112 million people (1, 2). In the UK, angina affects 3-4% of the adult population with 20,000 new cases each year (3). The majority of these patients improve symptomatically with interventions such as percutaneous coronary intervention (PCI) or coronary artery by-pass graft surgery (CABG) (4,32). However, there is a group of patients with refractory angina who are increasingly challenging to manage in clinical practice (4).