Cholesterol Crystal in Thrombus Removed by Mechanical Thrombectomy Should be a Strong Marker for Aortogenic Embolic Stroke

Abstract Aortogenic embolic stroke (AES) is an important stroke mechanism. However, as many stroke patients have aortic atheromatous lesions, it is unclear whether these lesions are the cause of these strokes. Cholesterol crystals are the solid, crystalline form of cholesterol that is found in atherosclerosis, but not in cardiac diseases such as atrial fibrillation, valvular diseases, and cardiomyopathy. Therefore, if a cholesterol crystal is found in a thrombus removed by mechanical thrombectomy (MT), this makes it possible to diagnose a patient as having an atheromatous lesion. Here, we report an AES case with a cholesterol crystal found in a thrombus removed by MT. A 67-year-old man was admitted due to consciousness disturbance, aphasia, and right hemiplegia. Diffusion-weighted imaging (DWI) showed a hyperintense area in the left frontal lobe, and magnetic resonance angiography demonstrated a branch occlusion of the left middle cerebral artery (MCA). MT was performed 1.5 h after stroke onset, with the thrombus removed and a left occluded MCA completely recanalized. Carotid duplex ultrasonography did not reveal any plaque in the carotid artery. Echocardiography did not show any abnormal function or findings, including thrombus. Transesophageal echocardiography showed a 4.9 mm atheromatous lesion at the aortic arch. Therefore, we suspected this patient as having an AES due to the embolic source of atheromatous lesion at the aortic arch. Pathological examination of the embolus revealed a cholesterol crystal cleft in the thrombus. Therefore, we diagnosed this patient as having AES caused by an atheromatous lesion at the aortic arch.