Microvascular angina (MVA) is caused by structural and functional abnormalities in microvascular coronary arteries smaller than 100 μm ; it is also known as coronary microvascular dysfunction (CMD). These abnormalities are difficult to visualize using coronary angiography, making the diagnosis of MVA challenging. We report a case of MVA that was diagnosed after the occurrence of chest pains during dental treatment under intravenous sedation. The patient was a 58-year-old man (height : 165 cm, weight : 60 kg, BMI : 22.0) with a history of a hyperactive gag reflex requiring intravenous sedation for dental treatment. Three years earlier, he had experienced chest pain during dental treatment, but a coronary spasm provocation test was negative and CMD was not evaluated. On the day of the presently reported treatment, the patient had stable vital signs. Propofol sedation and local anesthesia were administered. Shortly thereafter, he experienced nausea, convulsions, dizziness, and chest pain. The sedation was stopped, and the administration of sublingual nitroglycerin resolved his symptoms. He was transferred to the emergency room. A coronary angiography revealed no significant stenosis, and a coronary spasm was ruled out. An evaluation of coronary microvascular function showed a coronary flow reserve (CFR) of 2.3, an index of microvascular resistance (IMR) of 28, and a fractional flow reserve (FFR) of 0.91/0.91, leading to a diagnosis of MVA. This case highlights the need to consider MVA in patients with unexplained chest pain. Assessing coronary microvascular function is crucial for avoiding missed diagnoses and ensuring appropriate management.
