Invasive Assessment of Coronary Microvascular Function.

The critical role of the coronary microvascular compartment and its invasive functional assessment has become apparent in light of the significant proportion of patients presenting signs and symptoms of myocardial ischemia, despite the absence of epicardial disease, or after the adequate treatment of it. However, coronary microvascular dysfunction (CMD) represents a diagnostic challenge because of the small dimensions of the coronary microvasculature, which prevents direct angiographic visualization. Several diagnostic tools are now available for the invasive assessment of the coronary microvascular function, which, in association with the physiological indices used to investigate the epicardial department, may provide a comprehensive evaluation of the coronary circulation as a whole. Recent evidence suggests that the physiology-guided management of CMD, although apparently costly and time-consuming, may offer a net clinical benefit in terms of symptom improvement among patients with angina and ischemic heart disease. However, despite the results of several observational studies, the prognostic effect of the physiology-driven management of CMD within this population is currently a matter of debate, and therefore represents an unmet clinical need that urgently deserves further investigation.