Ischaemia with Non-Obstructive Coronary Artery Disease (INOCA) – Microvascular Angina

Around half of patients with stable angina and one in ten with acute coronary syndromes have normal or non-obstructed coronary arteries. It is suspected that this is due to structural or functional microcirculatory dysfunction or myocardial factors, such as left ventricular hypertrophy, increased myocardial pressure among others. Risk factors for INOCA are age, peri -and post-menopausal status, diabetes or dyslipidaemia, hypertension and left ventricular hypertrophy, as well as endothelial dysfunction and inflammation. The diagnosis relies on documentation of ischaemia during exercise, on ECG or imaging in the presence of non-obstructed coronary arteries. Outcomes may be good or impaired in a sub-group of patients, particularly those with markedly reduced coronary flow reserve. The management is currently not evidence-based and involves lifestyle changes, as well as a variety of anti-anginal drugs with mixed effectiveness.