Vasospastic Angina Masquerading as Plaque Erosion on Optical Coherence Tomography

BACKGROUND: Myocardial infarction with nonobstructive coronary arteries has diverse mechanisms, and reliance on intracoronary imaging alone may lead to misdiagnosis. CASE SUMMARY: A 70-year-old man presented with non-ST-segment elevation myocardial infarction. Coronary angiography showed no significant stenosis, whereas optical coherence tomography (OCT) demonstrated an intraluminal thrombus over a lipid-rich plaque with an intact fibrous cap, suggesting plaque erosion. After treatment including a β-blocker, he developed recurrent chest pain 2 months later. Repeat angiography was unchanged, but acetylcholine provocation induced multivessel coronary spasm. Follow-up OCT showed thrombus resolution with persistent layered plaque and intimal irregularities, supporting vasospasm-induced thrombosis. Symptoms resolved after switching from β-blocker therapy to vasodilators. DISCUSSION: This case highlights that coronary vasospasm can mimic plaque erosion on OCT. Functional testing and assessment of pharmacologic response are essential for accurate diagnosis and appropriate management of myocardial infarction with nonobstructive coronary arteries.