Abstract
Ischemia and no obstructive coronary artery disease (INOCA) is an increasingly recognized cause of angina, and it is more commonly diagnosed in women. Coronary microvascular dysfunction (CMD), or the abnormal dilation and constriction of the small vessels of the heart, is the underlying cause of INOCA in one-half of cases. This review discusses coronary microvascular pathophysiology, considerations for invasive coronary function testing and noninvasive diagnostic modalities, implications for management, and remaining knowledge gaps.