Central retinal artery occlusion caused by external carotid artery plaque dispersal during carotid artery stenting: A case report

Background: Central retinal artery occlusion (CRAO) is a serious complication caused by carotid artery plaque dispersal into the ophthalmic artery (OA) during carotid artery stenting (CAS). The purpose of this study is to determine the cause of CRAO despite CAS with both external carotid artery (ECA) and internal carotid artery (ICA) protection. Case Description: An 85-year-old man was hospitalized two years ago for cerebral infarction and was diagnosed with left carotid artery stenosis. Carotid ultrasound showed low-intensity plaque, and peak systolic velocity had worsened to 466 cm/s, and magnetic resonance imaging (MRI) also suggested unstable plaque. Angiography showed American Symptomatic Carotid Endarterectomy Trial (NASCET) 90% stenosis. Distal ICA was protected with Filter Wire EZ, and ECA and common carotid artery were protected with Mo.Ma Ultra, and CAS was performed using PRECISE Pro RX. Immediately after treatment, patient complained of visual field loss in the left eye, caused by CRAO. Conclusion: Risk factors for CRAO after CAS include older age, severe stenosis, and the OA fed from the ECA. In this case, ECA was protected with the Mo.Ma Ultra and ICA with the Filter Wire EZ, but the patient developed CRAO. No plaque in filter, no cerebral infarction at all on MRI, likely due to crushing of unstable plaque in the ECA during induction of the Mo.Ma Ultra. It is important to develop a treatment strategy after understanding the characteristics of the plaque and effective embolic protection.