ANOCA updated: From pathophysiology to modern clinical practice

Lately, a large number of stable ischemic patients, with no obstructed coronary arteries are being diagnosed. Despite this condition, which is being described as angina with no obstructive coronary arteries (ANOCA), was thought to be benign, recent evidence report that it is associated with increased risk for adverse cardiovascular outcomes. ANOCA is more frequent in women and, pathophysiologically, it is predominantly related with microvascular dysfunction, while other factors, such as endothelial dysfunction, inflammation and autonomic nervous system seem to also play a major role to its development, while other studies implicate ANOCA and microvascular dysfunction in the pathogenesis of heart failure with preserved ejection fraction. For establishing an ANOCA diagnosis, measurement including coronary flow reserve (CFR), microvascular resistance (IMR) and hyperemic microvascular resistance (HMR) are mostly used in clinical practice. In addition, new modalities, such as optical coherence tomography (OCT) are being tested and show promising results for future diagnostic use. Regarding management, pharmacotherapy consists of a wide selection of drugs, according to the respected pathophysiology of the disease (vasospastic angina or microvascular dysfunction), while research for new treatment options including interventional techniques, is currently ongoing. This review, therefore, aims to provide a comprehensive analysis of all aspects related to ANOCA, from pathophysiology to clinical managements, as well as clinical implications and suggestions for future research efforts, which will help advance our understanding of the syndrome and establish more, evidence-based, therapies.