Rapid Plaque Progression in a Patient with Non-ST-Segment Elevation Acute Coronary Syndrome: A Case Report

Acute coronary syndrome (ACS), diagnosed by optical coherence tomography (OCT), is caused primarily by plaque rupture, plaque erosion, and calcified nodules. Plaque erosion is more common in patients with non-ST-segment elevation myocardial infarction than ST-segment elevation myocardial infarction. This study reports the details of a case of ACS caused by massive thrombus formation due to plaque erosion. The factors associated with plaque erosion and thrombosis could not be confirmed on the basis of clinical examination findings and the physicians’ experience; therefore, the initial diagnosis of an ischemic event was replaced by a diagnosis of rapid plaque progression, as microscopically confirmed by OCT. Therefore, OCT examination must be performed for blurred or “rapidly progressing” lesions identified through angiography.