Acute retinal arterial ischemia: an emergency often ignored

Intra-arterial Thrombolysis for Acute Retinal Ischemia: A Retrospective, Observational, Cohort Study

BACKGROUND

To determine whether intra-arterial thrombolysis (IAT) within 16 hours after the onset of symptoms is feasible and associated with better visual outcomes in patients with acute retinal ischemia (ARI).

METHODS

The retrospective cohort study was performed from January 2014 to December 2021 in the Xuanwu Hospital of Capital Medical University. Patients with ARI who initially presented visual acuity of 20/100 or worse were screened in the study. Visual end points were evaluated at one week and at final visit after treatment. Serious adverse events were recorded during operation and within 1 week after IAT treatment.

RESULTS

The amount of clinically significant visual improvement (≥0.3 logarithm of the minimum angle of resolution) in the IAT group was significantly higher than that in the conservative treatment group at one week after the treatment (47.8% vs 16.7%; P = 0.014) and at final visit (52.2% vs 20%; P = 0.014). After controlling confounding factors, ARI treatment was the only factor significantly associated with the amount of clinically significant visual improvement (OR, 4.364; 95 CI, 1.298-14.667; P = 0.017). A patient (4.3%) experienced retinal hemorrhage without symptom within 1 week after IAT treatment. No patients experienced new symptomatic cerebral infarction, intracranial hemorrhage, TIA, artery dissection, vascular perforation, and distal embolization during operation and within 1 week after IAT treatment.

CONCLUSIONS

IAT may be associated with better visual improvement within 16 hours after the onset of symptoms. Besides, IAT is feasible and associated with a low risk of periprocedural complications for ARI. This study will aid in feasibility testing and sample size calculations in advance of future, fully-powered efficacy studies for ARI.

Risk and risk factor of ischemic stroke after acute retinal arterial ischemia

PURPOSES

We aimed to confirm the risk and risk factor for ischemic stroke after acute retinal arterial ischemia (ARAI).

METHODS

A retrospective cohort study of patients with a diagnosis of acute retinal arterial ischemia (ARAI) and completing 2-year follow-up was conducted from January 2015 to December 2021 at a general hospital.

RESULTS

A total of 69 patients including 43(62.3%) patients of central retinal artery occlusion (CRAO), 11(15.9%) patients of branch retinal artery occlusion (BRAO) and 15(21.7%) patients of ophthalmic artery occlusion (OAO) were included in the study. Patients age was 58.2 ± 13.0(years), male patients accounting for 51 (73.9%) and 22 (31.9%) patients having at least 70% ipsilateral carotid artery stenosis (ICAS). During the 2-years follow-up period, 11(15.9%) patients of ARAI experienced ischemic stroke. Among them, 3(20%) patients of OAO, 6(14%) patients of CRAO and 2(18.2%) patients of BRAO had ischemic stroke. The cumulative probabilities of ischemic stroke were 13.0% at 12.9 months and 15.9% at 24 months after ARAI. In addition, patients with at least 70% ICAS were more likely than patients without it to have ischemic stroke (p = 0.002). After Cox regression analysis, ICAS (≥ 70%) or occlusion was significantly associated with a high risk of ischemic stroke after ARAI during the 2-years follow-up time (HR,6.769,95%CI [1.792-25.578], p = 0.005).

CONCLUSION

Patients have a high risk of ischemic stroke, particularly those with a diagnosis of ICAS (≥ 70%) or occlusion after the onset of ARAI. Clinical management of ARAI should focus on vascular risk factors control and secondary prevention for stroke.

CASE SERIES OF HYPERBARIC OXYGEN THERAPY FOR CENTRAL RETINAL ARTERY OCCLUSION

PURPOSE

To retrospectively report the outcomes of patients presenting to our facility with central retinal artery occlusion and receiving therapy with hyperbaric oxygen (HBO).

METHODS

This was a retrospective, chart review at a single hospital center. Patients with diagnosed central retinal artery occlusion were treated with HBO twice daily for 5 days during their inpatient stay for a total of 10 HBO treatments. Main outcome was change from the documented presenting best-corrected visual acuity to discharge best-corrected visual acuity. Thirty-nine patients with central retinal artery occlusion were included in the analysis during a 30-month period.

RESULTS

Twenty-eight of 39 patients (72%) had some improvement in acuity. There was a mean of 5.05 lines of improvement using a modified Snellen chart after completing their HBO treatment course. Patients treated within 12 hours of symptom onset showed the greatest improvement in their visual acuity (6.11 mean lines of improvement). Complications of therapy included middle ear barotrauma (10/39) and confinement anxiety (1/39) and did not interfere with the therapy regimen or hospital course.

CONCLUSION

This retrospective case series supports the use of emergent HBO therapy as a viable treatment option for patients with central retinal artery occlusion. Hyperbaric oxygen therapy was safely administered and well tolerated.

Thrombolysis for Central Retinal Artery Occlusion in 2020: Time Is Vision!

BACKGROUND

Acute nonarteritic central retinal artery occlusion (CRAO) is an eye stroke with poor visual prognosis and no proven effective therapies. Given advances in acute stroke care, thrombolysis in CRAO merits critical re-examination. We review the evidence for intravenous (IV) and intra-arterial (IA) tissue plasminogen activator (tPA) in CRAO management.

EVIDENCE ACQUISITION

MEDLINE, Scopus, and Cochrane online databases were systematically searched from 1960 to present, for reports of acute IV or IA therapy with alteplase or tenecteplase in nonarteritic CRAO patients. English language case reports, case series, interventional studies, or randomized controlled trials were included. The study type, age and number of subjects, the regimen administered, the time since symptoms' onset, visual outcome, and safety reports were noted.

RESULTS

Use of IV thrombolysis with alteplase was reported in 7 articles encompassing 111 patients, with 54% of them receiving IV tPA within 4.5 hours of symptom onset, and none developing symptomatic intracranial or ocular hemorrhage. Six studies described IA alteplase administration, with only 18 of a total of 134 patients (13.4%) treated within the first 6 hours after visual loss. The reported adverse events were minimal. Visual outcomes post-IV and IA thrombolysis were heterogeneously reported; however, most studies demonstrated benefit of the respective reperfusion therapies when administered very early. We found no reports of tenecteplase administration in CRAO.

CONCLUSIONS

In 2020, nonarteritic CRAO patients should theoretically receive the same thrombolytic therapies, in the same time window, as patients with acute cerebral ischemia. Eye stroke and teleeye stroke code encounters must include an expert ophthalmologic evaluation to confirm the correct diagnosis and to evaluate for ocular signs that may help guide IV tPA administration or IA management. Future research should focus on developing feasible retinal penumbra imaging studies that, similar to cerebral tissue viability or perfusion imaging, can be incorporated into the thrombolysis decision-making algorithm.

Study to elucidate the pharmacological activity of retinalamin in a rat model of ischemic retinopathy

Introduction: Over the past few years, the incidence of retinal ischemic disorders has been increasing, due to a rising prevalence of such socially burdensome diseases as diabetes and hypertension, which ultimately lead to ocular vascular pathology. The identification of new treatment options that would prevent retinal neuron death is a crucial task of modern pharmacology.

Materials and methods: The research was carried out on male Wistar rats. Retinopathy was modeled by inducing a 30-min ischemic episode, with a 72-hour period of reperfusion and subsequent administration of Retinalamin and Emoxypine for 10 days. The effectiveness of the drugs was evaluated by electroretinographic, ophthalmoscopic and morphological assessments.

Results and discussion: On Day 14 of the experiment, a dose-dependent preservation of the electroretinogram b-wave/a-wave amplitude ratio was observed in the animals treated with Retinalamin depending on a dose (1.39±0.06, 1.46±0.03 and 1.49±0.04 in low (0.214 mg/kg), medium (0.428 mg/kg) and high (0.857 mg/kg) Retinalamin dose groups, respectively). The ophthalmoscopic picture of the fundus oculi also improved following the treatment with Retinalamin (1.42, 1.69 and 1.90 times lower ophthalmoscopic scores compared to placebo-treated animals in low, medium and high dose groups, respectively). The morphologic “coefficient of change” applied to ganglion cell layer was 2.2, 1.7 and 1.6 points in low, medium and high dose Retinalamin groups, respectively. These results are significantly different from both intact and placebo group (p<0.05). Based on the aforementioned experimental findings, we conclude that Retinalamin has a retinoprotective effect and is superior to the drug of comparison (Emoxypine).

Conclusion: The greatest neuroprotective effects were shown in the groups receiving Retinalamin. In these groups, the ERG b-wave/a-wave amplitude ratio was preserved, the ophthalmoscopic picture was less pathologic and retinal morphology features were close to those of the intact retina.

Retinal vascular occlusions

Acute retinal vascular occlusions are common causes of visual impairment. Although both retinal artery occlusions and retinal vein occlusions are associated with increased age and cardiovascular risk factors, their pathophysiology, systemic implications, and management differ substantially. Acute management of retinal artery occlusions involves a multidisciplinary approach including neurologists with stroke expertise, whereas treatment of retinal vein occlusions is provided by ophthalmologists. Optimisation of systemic risk factors by patients' primary care providers is an important component of the management of these two disorders.

Conservative treatments for acute nonarteritic central retinal artery occlusion: Do they work?

Acute central retinal arterial occlusion has a very poor visual prognosis. Unfortunately, there is a dearth of evidence to support the use of any of the so-called “conservative” treatment options for CRAO, and the use of thrombolytics remains controversial. In this review, we address a variety of these “conservative” pharmacologic treatments (pentoxifylline, isosorbide dinitrate, and acetazolamide) and nonpharmacologic approaches (carbogen, hyperbaric oxygen, ocular massage, anterior chamber paracentesis, laser embolectomy, and hemodilution) that have been proposed as potential treatments of this condition. We conclude that the available evidence for all treatments is insufficient to conclude that any treatment will influence the natural history of this disorder. Management of CRAO patients should instead focus on reducing the risk of subsequent ischemic events, including cerebral stroke. Certain patients may be considered for acute treatment with thrombolytics, although further research must clarify the efficacy, safety, and optimal use of these therapies.

Standard Diffusion-weighted MRI for the Diagnosis of Central Retinal Artery Occlusion

Purpose

To evaluate diffusion abnormalities of the retina and optic nerve in patients with central retinal artery occlusion (CRAO) using standard stroke diffusion-weighted magnetic resonance imaging (DWI).

Methods

In this case-control study, DWI scans of patients with nonarteritic CRAO were retrospectively assessed for acute ischemia of the retina and optic nerve. Two neuroradiologists, blinded for patient diagnosis, randomly evaluated DWI of CRAO patients and controls (a collective of stroke and transient ischemic attack [TIA] patients) for restrictions of the retina and optic nerve. We calculated statistical quality criteria and analyzed inter-rater reliability using unweighted Kappa statistics.

Results

20 CRAO patients (60,6 ± 17 years) and 20 controls (60,7 ± 17 years) were included in the study. Sensitivity, specificity, positive and negative predictive values for retinal DWI restrictions were 75%/80%/79%/76% (reader 1) and 75%/100%/100%/80% (reader 2), respectively. Unweighted Kappa was κ = 0,70 (95% CI 0,48‑0,92), indicating “substantial” interrater reliability. In comparison, sensitivity, specificity, PPV and NPV (positive and negative predictive values) for restrictions of the optic nerve in CRAO were 55%/70%/65%/61% (reader 1) and 25%/100%/100%/57% (reader 2). Inter-rater reliability was “fair” with unweighted Kappa κ = 0,32 (95% CI 0,09‑0,56).

Conclusions

Retinal diffusion restrictions were present in a majority of CRAO patients and detectable with reasonable sensitivity, high specificity and substantial inter-rater reliability. Further studies are necessary to study time dependency of retinal diffusion restrictions, improve image quality and investigate the reliability of retinal DWI to discern CRAO from other causes of acute loss of vision.

Electronic supplementary material

The online version of this article (10.1007/s00062-020-00955-6) contains supplementary material, which is available to authorized users.

Do Patients With Retinal Artery Occlusion Need Urgent Neurologic Evaluation?

PURPOSE

To describe a framework for logical, immediate action to manage patients with retinal artery occlusion.

DESIGN

Literature review and perspective.

METHODS

Review of the literature and the author's experience.

RESULTS

Since embolism is the most common factor causing retinal artery occlusion, to manage these patients, immediate evaluation and management of the source of embolism is critical to prevent further episodes.

CONCLUSIONS

The logical, immediate action to manage patients with retinal artery occlusion is evaluation of the carotid artery and heart for embolism, fasting lipid levels and a complete blood count, rather than neurological evaluation, unless, of course, there are neurological symptoms.

Acute retinal arterial ischemia

Acute retinal arterial ischemia, which includes transient monocular vision loss (TMVL), branch retinal artery occlusion (BRAO), central retinal artery occlusion (CRAO) and ophthalmic artery occlusion (OAO), is most commonly the consequence of an embolic phenomenon from the ipsilateral carotid artery, heart or aortic arch, leading to partial or complete occlusion of the central retinal artery (CRA) or its branches. Acute retinal arterial ischemia is the ocular equivalent of acute cerebral ischemia and is an ophthalmic and medical emergency. Patients with acute retinal arterial ischemia are at a high risk of having further vascular events, such as subsequent strokes and myocardial infarctions (MIs). Therefore, prompt diagnosis and urgent referral to appropriate specialists and centers is necessary for further work-up (such as brain magnetic resonance imaging with diffusion weighted imaging, vascular imaging, and cardiac monitoring and imaging) and potential treatment of an urgent etiology (e.g., carotid dissection or critical carotid artery stenosis). Since there are no proven, effective treatments to improve visual outcome following permanent retinal arterial ischemia (central or branch retinal artery occlusion), treatment must focus on secondary prevention measures to decrease the likelihood of subsequent ischemic events.

Management of Acute Retinal Ischemia: Follow the Guidelines!

Acute retinal arterial ischemia, including vascular transient monocular vision loss (TMVL) and branch (BRAO) and central retinal arterial occlusions (CRAO), are ocular and systemic emergencies requiring immediate diagnosis and treatment. Guidelines recommend the combination of urgent brain magnetic resonance imaging with diffusion-weighted imaging, vascular imaging, and clinical assessment to identify TMVL, BRAO, and CRAO patients at highest risk for recurrent stroke, facilitating early preventive treatments to reduce the risk of subsequent stroke and cardiovascular events. Because the risk of stroke is maximum within the first few days after the onset of visual loss, prompt diagnosis and triage are mandatory. Eye care professionals must make a rapid and accurate diagnosis and recognize the need for timely expert intervention by immediately referring patients with acute retinal arterial ischemia to specialized stroke centers without attempting to perform any further testing themselves. The development of local networks prompting collaboration among optometrists, ophthalmologists, and stroke neurologists should facilitate such evaluations, whether in a rapid-access transient ischemic attack clinic, in an emergency department-observation unit, or with hospitalization, depending on local resources.

Fundus autofluorescence in retinal artery occlusion: A more precise diagnosis

IMPORTANCE

Retinal artery occlusion (RAO) is a medical emergency associated with a high risk of cerebral vascular accident and other cardiovascular events. Among patients with non-arteritic RAO, a retinal embolus is observed in approximately 40% of cases. Fundus examination and retinography are not reliable to predict the nature of the emboli.

OBSERVATIONS

We report three consecutive cases of central and branch RAO that were investigated with fundus autofluorescence, fluorescein angiography and color retinal photographs. All patients underwent complete neurological and cardiovascular workups, with brain imaging, cardiac Doppler ultrasound, carotid Dopplers and Holter ECG's, to determine the underlying mechanism of retinal embolism. In the three cases, aged 77.7±4 years (2 women and 1 man), fundus autofluorescence demonstrated hyperautofluorescent emboli. In two cases, it allowed visualization of emboli that were not detected with fundus examination or retinography. The cardiovascular work-up demonstrated atheromatous carotid or aortic plaques in all patients. In one case, it permitted the diagnosis of RAO. Two of the three cases were considered to be of atherosclerotic origin and one of undefined origin.

CONCLUSION AND RELEVANCE

Fundus autofluorescence may help to detect and characterize retinal emboli. Since lipofuscin, which is present in large quantity in atherosclerotic plaques, is the main fluorophore detected with fundus autofluorescence, this non-invasive and simple examination may give information about the underlying mechanism of retinal embolism, and thus impact the etiologic assessment of RAO. Additional studies are necessary to confirm this potential role of autofluorescence.

Update on the Management of Central Retinal Artery Occlusion

Central retinal artery occlusion (CRAO) is caused by partial or complete occlusion of the central retinal artery, most commonly by an embolus from the ipsilateral carotid artery, aortic arch, or heart, and is the ocular equivalent of an acute cerebral ischemic event. The risk factors for a CRAO and acute cerebral ischemia are very similar, if not identical. Because no current therapeutic intervention has been shown to improve visual outcomes compared with the natural history of CRAO, management of CRAO should be focused on secondary prevention of vascular events, such as cerebral ischemia, myocardial infarction, and cardiovascular death.

Practice Patterns After Acute Embolic Retinal Artery Occlusion

PURPOSE

To compare stroke evaluations recommended by retina special-ists and neurologists for retinal artery occlusion (RAO).

DESIGN

A cross-sectional survey.

METHODS

An anonymous survey was emailed to members of the American Academy of Neurology Stroke Section listserv and vitreoretinal specialists registered with the American Academy of Ophthalmology. The survey was divided based on duration of symptoms before encounter: less than 12 hours, 24-48 hours, and more than 1 week. Institutional review board approval was obtained before data collection.

RESULTS

Four hundred forty-eight surveys were completed (281 retinologists and 167 neurologists). Within 12 hours of RAO, most neurologists (75%) pursue a hospital-based evaluation, whereas the majority of retinologists (82%) pursue outpatient workup (P < 0.0001). Most neurologists (92%) and retinologists (98%) pursue outpatient stroke workup if symptoms have been present for more than 7 days.

CONCLUSIONS

Neurologists pursue higher acuity care after RAO, whereas most retinologists order outpatient evaluations. Retina specialists should consider urgent stroke evaluation to mitigate stroke risk factors.

Retinal Vascular Changes are a Marker for Cerebral Vascular Diseases

The retinal circulation is a potential marker of cerebral vascular disease because it shares origin and drainage with the intracranial circulation and because it can be directly visualized using ophthalmoscopy. Cross-sectional and cohort studies have demonstrated associations between chronic retinal and cerebral vascular disease, acute retinal and cerebral vascular disease, and chronic retinal vascular disease and acute cerebral vascular disease. In particular, certain qualitative features of retinopathy, retinal artery occlusion, and increased retinal vein caliber are associated with concurrent and future cerebrovascular events. These associations persist after accounting for confounding variables known to be disease-causing in both circulations, which supports the potential use of retinal vasculature findings to stratify individuals with regards to cerebral vascular disease risk.

Retinal Artery Occlusion and the Risk of Stroke Development: Twelve-Year Nationwide Cohort Study

BACKGROUND AND PURPOSE

Our aim was to evaluate the risk of subsequent stroke development after retinal artery occlusion (RAO).

METHODS

National registry data were collected from the Korean National Health Insurance Service, comprised 1 025 340 random subjects. Patients diagnosed with RAO in 2002 and 2003 were excluded. The RAO group was composed of patients with an initial diagnosis of either central or other RAO between January 2004 and December 2013 (n=401). The comparison group was composed of randomly selected patients (5 per RAO patient; n=2003) who were matched to the RAO group according to sociodemographic factors and year of RAO diagnosis. Each sampled patient was tracked until 2013. Cox proportional hazard regression was used.

RESULTS

Stroke occurred in 15.0% of the RAO group and in 8.0% of the comparison group (P < 0.001). RAO was associated with an increased risk of stroke occurrence (hazard ratio, 1.78; 95% confidence interval, 1.32-2.41). The magnitude of the RAO effect for stroke was larger among younger adults aged <65 years (hazard ratio, 3.11) than older adults aged ≥65 years (hazard ratio, 1.26). However, the risk of subsequent stroke was significantly increased in older adults aged ≥65 years at the 4-year follow-up (hazard ratio, 1.58; 95% confidence interval, 1.01-2.48).

CONCLUSIONS

RAO was significantly associated with subsequent stroke after adjusting for comorbidities and sociodemographic factors. These findings are limited by uncontrolled confounding factors and need to be replicated by other observational studies.

Retrobulbar Spot Sign Predicts Thrombolytic Treatment Effects and Etiology in Central Retinal Artery Occlusion

BACKGROUND AND PURPOSE

Transorbital sonography may help establish diagnosis of central retinal artery occlusion (CRAO). Next to Doppler sonographic proof of CRAO, an intra-arterial spot sign can be detected in some cases. We hypothesized that it reflects calcified components. It may be associated with embolization from atherosclerotic plaques and may negatively influence thrombolysis.

METHODS

Prospective monocenter study of 46 patients with ophthalmologically confirmed CRAO. Systemic tissue-type plasminogen activator thrombolysis was performed when appropriate. All patients received etiologic workup.

RESULTS

CRAO was confirmed by Doppler in all patients. Fifty-nine percent of patients with arterio-arterial embolization were spot sign-positive compared with 20% from cardiac source (P<0.05) and none with vasculitis. Eleven patients underwent thrombolysis. Clinically relevant visual improvement was only found in absence of a spot sign (P<0.05).

CONCLUSIONS

Transbulbar ultrasound is valuable for initial diagnosis and diagnostic workup of CRAO. In the light of inconsistent results of previous thrombolysis trials, ultrasound may identify patients more likely to benefit from thrombolytic treatment.

Retinal and optic nerve ischemia

PURPOSE OF REVIEW

This review focuses on aspects of retinal and optic nerve ischemia that may be encountered by neurologists.

RECENT FINDINGS

Recent guidelines have emphasized the similarities between cerebral and retinal ischemia in terms of etiologic workup, acute management, and subsequent stroke risk. However, although ischemic optic neuropathies reflect optic nerve ischemia, they result from local small vessel disease and are not associated with a higher risk of cerebral infarction. Their management is therefore very different from acute cerebral ischemia. It is essential to rule out giant cell arteritis in all patients with acute retinal or optic nerve ischemia.

SUMMARY

Because the eye is vascularized by branches of the internal carotid artery, retinal ischemic symptoms are common in patients with anterior circulation ischemic strokes. Patients with central retinal artery occlusion, whether permanent or transient (responsible for transient visual loss), need to be evaluated and managed emergently similar to patients with cerebral ischemia, while anterior and posterior ischemic optic neuropathy are more concerning for giant cell arteritis.