Acute coronary syndromes typically result from the formation of atherosclerotic lesions in a large epicardial vessel, which restrict blood flow either partially or completely. These lesions can be identified through angiography, an invasive imaging technique that enables visualization of the coronary arteries. However, a small percentage of patients, usually ranging from 5% to 10%, experience symptoms and/or signs of myocardial ischemia, either acute or chronic, without significant obstructive coronary lesions visible on angiography. This condition is particularly prevalent in young women and is characterized by two distinct forms: myocardial infarction with no obstructive coronary arteries (MINOCA) and myocardial ischemia with no obstructive coronary arteries (INOCA). MINOCA can be caused by a variety of heterogeneous mechanisms, including coronary vascular spasm, microvascular disease, spontaneous coronary dissection, and plaque rupture or erosion. Conversely, coronary vasospasm and microvascular dysfunction account for the majority of patients with INOCA. We here present three cases of MINOCA/INOCA that were evaluated using optical coherence tomography, coronary flow reserve, index of microcirculatory resistance, and acetylcholine provocative test. These diagnostic tests allowed us to identify a specific condition and adopt a targeted treatment for each patient.