Retinal Ischemia and Embolism

Abstract

Objectives: To identify the most likely mechanisms of retinal ischemia and embolism in a hospital-referred population, and to determine the frequency of recurrent vascular events during the 3-month period following initial presentation. Methods: Consecutive patients presenting to 2 tertiary medical centers and their outpatient clinics were prospectively enrolled over a 22-month period. Eligible patients presented with histories of transient or permanent monocular visual loss, or had evidence of asymptomatic retinal embolism on routine ophthalmological examination. They underwent a rapid and standardized evaluation that included imaging studies as well as blood tests, and follow-up was obtained at 1 and 3 months. Results: Seventy-seven patients were enrolled. Enrollment diagnoses consisted of amaurosis fugax (n = 32), asymptomatic retinal embolism (n = 34), and central or branch retinal artery occlusion (n = 11). Eight different presumed etiologies of retinal artery distribution embolism or hypoperfusion were identified. Extracranial internal carotid artery occlusion or more than 50% stenosis was observed in 17/77 (22.1%) cases, making it the largest etiologic subgroup. Uncommon but treatable conditions were identified in 8/77 (10.4%) patients, and an etiologic diagnosis could not be made in 35/77 (45.5%) patients. Recurrent events occurred in, respectively, 14/77 (18.2%) and 6/73 (8.2%) patients at the 1- and 3-month follow-ups. They included 2 infarcts and 2 deaths; ischemic events of the retina were more common than those involving the brain. Conclusion: Severe stenosis of the extracranial internal carotid artery is the most common identified condition associated with retinal ischemia and embolism, but a variety of other, potentially treatable, conditions can be diagnosed if appropriate and specific evaluations are conducted. The frequency of recurrent vascular ischemic events is highest during the 1st month of follow-up and decreases during the 2nd and 3rd months. Recurrences range from relatively innocuous episodes of amaurosis fugax to vascular death.

Retinal artery occlusion and associated recurrent vascular risk with underlying etiologies

“…Previous studies have reported that the incidence of experiencing a subsequent stroke was highest in the first month after retinal ischemia. [7, 11, 12, 16] Considering these findings, early treatment and appropriate interventions, such as carotid endarterectomy or carotid stenting, may be carefully considered for the prevention of a second vascular event.…”

“…Babikian et al reported that the most common identifiable etiology (22.1%) of RAO in American subjects was stenosis of the extracranial carotid artery and OA stenosis was reported in only 2.6%. [11] However, Asians have a higher incidence of intracranial atherosclerosis than Caucasians. Anatomically, the retinal artery arises from the OA, the first intracranial branch of the internal carotid artery.…”

“…In previous studies, the vascular risk factors that predispose patients to atherosclerotic disease were present in a larger proportion of patients with RAO than that seen in the general population. [8, 11, 19] Cardioembolism as an etiology, such as atrial fibrillation and valvular heart disease, was present in 6% of RAO patients. Leisser et al reported about 4.3% of patients with vegetations on the cardiac valves and 10.3% of patients with other reasons for possible cardioembolism diagnosed with TEE.…”

From amaurosis fugax to asymptomatic bithalamic infarct

“…However, cardiac lesions appear to be the second cause of importance [5]. When cardio-embolic origin of stroke is suspected, achieving the appropriate screening is crucial.…”

Selective Over-Expression of Endothelin-1 in Endothelial Cells Exacerbates Inner Retinal Edema and Neuronal Death in Ischemic Retina

“…As indicated by Kaja et al, this model is able to recapitulate the cellular and molecular changes in the retina after stroke. This is particularly clinically relevant since acute thrombotic/embolic stroke and transient ischemic attack in humans are often associated with temporary diminishment (ie, amaurosis fugax) or even permanent loss of vision [26].…”