Management of Transient Monocular Vision Loss and Retinal Artery Occlusions

Risk factors for ischemic cerebral stroke in patients with acute amaurosis fugax

OBJECTIVE

The National Stroke Association and the American Heart Association consider retinal ischemia, as in the case of amaurosis fugax (AF), to be a stroke event. The purpose of this study was to evaluate the risk factors for ischemic cerebral stroke in patients hospitalized for acute AF.

METHODS

The National Inpatient Sample Database from 2002 to 2014 was used to identify patients 21 years of age and older with a primary admission diagnosis of AF with the ICD-9 code 362.34. Comorbidity measures and in-hospital events were extracted using relevant ICD-9 codes. Statistical analyses were performed using IBM SPSS 25 and R package.

RESULTS

A weighted total of 12,142 patients was identified. The most common comorbidities in this cohort with AF included hypertension, dyslipidemia, tobacco use, coronary artery disease (CAD), and diabetes mellitus. Multivariable regression analysis showed comorbidities of hypercoagulable state, systemic vasculitis, CAD, and atherosclerosis to be independent risk factors for ischemic stroke in patients with AF. In contrast, dyslipidemia was associated with a decreased risk. Asian/Pacific Islander race conferred a 5-fold increased risk compared with Whites.

CONCLUSION

Ischemic stroke and myocardial infarction were diagnosed in 0.3%-0.9% of hospitalized acute AF cases. Presence of hypercoagulable state, systemic vasculitis, CAD, and atherosclerosis each individually increased the risk of ischemic stroke by more than 3-fold; patients with these risk factors and acute AF should be closely monitored for developing acute systemic thrombotic events.

Risk Factors and Treatment Strategy for Retinal Vascular Occlusive Diseases

Retinal occlusive diseases are common diseases that can lead to visual impairment. Retinal artery occlusion and retinal vein occlusion are included in the clinical entity, but they have quite different pathophysiologies. Retinal artery occlusion is an emergent eye disorder. Retinal artery occlusion is mainly caused by thromboembolism, which frequently occurs in conjunction with life-threatening stroke and cardiovascular diseases. Therefore, prompt examinations and interventions for systemic vascular diseases are often necessary for these patients. Retinal vein occlusion is characterized by retinal hemorrhage and ischemia, which may impair visual function via several complications such as macular edema, macular ischemia, vitreous hemorrhage, and neovascular glaucoma. Even though anti-vascular endothelial growth factor therapy is the current established first-line of treatment for retinal vein occlusion, several clinical studies have been performed to identify better treatment protocols and new therapeutic options. In this review, we summarize the current findings and advances in knowledge regarding retinal occlusive diseases, particularly focusing on recent studies, in order to provide an update for a better understanding of its pathogenesis.

Recurrent migraine with binocular transient vision loss associated with acute stroke: A case report

INTRODUCTION

Amaurosis fugax (AF) refers to monocular transient vision loss (TMVL) or binocular transient vision loss (TBVL). TBVL is less common than TMVL and may be due to cortical lesions. TVL can be associated with stroke and thus merits urgent evaluation. Here, we report a case of recurrent migraine associated with TBVL in an adult patient.

CASE PRESENTATION

A 45-year-old male presented at the eye clinic complaining of an acute episodic of TBVL lasting three consecutive days with complete spontaneous recovery. He had a history of hypertension with blood pressure 143/94 mmHg. While in the clinic, he experienced a TVL attack that persisted for 5 min. We immediately referred him to the hospital for a magnetic resonance angiogram (MRA) scan and laboratory workup. While waiting for the examination results the next day, the patient had a seizure and became unconscious. He was admitted to the emergency room and then to the intensive care unit (ICU). The MRA showed post-hemorrhagic encephalomalacia in the internal capsule's right basal ganglia/right anterior limb. Fundoscopy showed an empty vessel and cotton-wool spots, which were consistent with hypertensive retinopathy. The patient was diagnosed with bilateral AF due to hemorrhagic stroke and hypertensive retinopathy. He was treated by a neurologist, and 3 days after being discharged he presented at the eye clinic with a visual acuity of 20/25 in both eyes.

CONCLUSION

Recurrent migraine with TBVL can be associated with acute stroke. It thus merits urgent evaluation and referral to the relevant department for a better outcome.

Central retinal artery occlusion as a neuro-ophthalmological emergency: the need to raise public awareness

BACKGROUND AND PURPOSE

Central retinal artery occlusion (CRAO) is a neuro-ophthalmological emergency necessitating adequate and comprehensive diagnosis. Its optimal management and treatment, however, are still under debate. This study aimed at identifying respective areas for improvement.

METHODS

We retrospectively analysed the medical records of patients with CRAO treated in our stroke unit between January 2016 and August 2020.

RESULTS

During the observational period, 101 patients with CRAO were admitted. We observed an increase in the rate of patients primarily admitted to the stroke unit from 52.2% to 97.4%. In addition, the thrombolysis rate - with thrombolysis performed on an individual basis - rose from 0% to 14.1%, coinciding with the implementation of an in-hospital management guideline. Almost 60% of all patients presented outside of the 4.5-h time window for thrombolysis; by far the most common reason not to deliver intravenous thrombolysis in our cohort was a prehospital delay to presentation (58.8%), with 44.4% of patients having consulted a private-practice ophthalmologist first. A total of 25 (32.5%) of 77 patients who underwent magnetic resonance imaging (MRI) had accompanying acute ischaemic stroke lesions on diffusion-weighted MRI of the brain. A possible aetiology of CRAO was identified in 41.4% of patients.

DISCUSSION

Public awareness of sudden unilateral visual loss as a presenting sign for stroke should be raised, increasing the chances for timely recognition in a hospital with ophthalmological expertise and a stroke centre. This is essential for ongoing and future prospective trials on this subject.

The Retrobulbar Spot Sign and Prominent Middle Limiting Membrane as Prognostic Markers in Non-Arteritic Retinal Artery Occlusion

Central retinal artery occlusion (CRAO) is characterized by the sudden, painless loss of vision. Typical sonographic and optic coherence tomography (OCT) findings are a retrobulbar spot sign and prominent middle limiting membrane (p-MLM) sign. It remains uncertain whether the retrobulbar spot sign alone or coinciding with the appearance of p-MLM sign is a prognostic marker for visual acuity and the development of secondary retinal ischemia after CRAO. In our prospective cohort study, we included patients with a non-arteritic central artery occlusion < 4 weeks. We examined the following parameters at prespecified time points: ultrasound examination of orbital cavity, Spectral Domain-OCT examination, visual acuity test, and fundoscopy and ultra-widefield angiography to diagnose retinal vascularization. The presence of p-MLM sign in SD-OCT after CRAO was accompanied by significantly better vision during the first four weeks (2.3 (IQR 0.75) vs. 2.6 (IQR 0.33); p = 0.006). Moreover, the spot sign seems to be a prognostic factor for developing secondary retinal ischemia (8 (100%) vs. 0 (0%); p = 0.036). A retrobulbar spot sign seems to be a negative prognostic factor and is associated with secondary retinal ischemia, whereas a p-MLM sign is a somewhat positive prognostic factor for visual acuity.

Transient Monocular Visual Loss: When Is It an Emergency?

BACKGROUND

Patients who experienced transient monocular vision loss (TMVL) commonly present to the emergency department for evaluation. Although multiple etiologies can cause TMVL, it is most important to identify patients with retinal ischemia and those with vasculitis (giant cell arteritis) as the cause of TMVL. Patients with transient retinal ischemia have the same risk of cardiovascular events and death as patients who experienced transient brain ischemia. Patients with giant cell arteritis are at imminent risk of visual loss.

CASE REPORT

A 65-year-old man noticed three separate episodes of sudden onset of blurry vision in one eye. Ophthalmologic examination was normal but, as his symptoms were compatible with transient retinal ischemic attack, urgent investigations were initiated. He had normal inflammatory markers but computed tomography angiogram of the brain and neck demonstrated a large plaque in the ipsilateral internal carotid artery. Double anti-platelet therapy was started and stenting of the involved carotid artery was performed. The patient was symptom-free at the last follow-up. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: Patients with retinal ischemia as the etiology of TMVL are at high risk of cardiovascular events and death. Their risk of cerebrovascular accidents is highest within 48 h from the episode of TMVL, thus they should have an urgent ophthalmologic examination and, if it is unrevealing, inflammatory markers should be checked and an urgent stroke prevention protocol should be initiated. Appropriate management with medical or surgical interventions significantly reduces morbidity and mortality in these patients.

Retinal artery occlusion does not portend an increased risk of stroke

OBJECTIVE

The aim of this study was to determine the subsequent risk of stroke after a diagnosis of retinal artery occlusion (RAO). We hypothesized that the risk would be low and comparable to that of the general population. RAO is relatively rare and often incorrectly diagnosed. We believe our institution is in a unique position to investigate this relationship with both a high-volume eye center and vascular laboratory.

METHODS

This was a retrospective, single-institution review of 221 patients diagnosed with RAO from 2004 to 2018, confirmed with fluorescein angiography. Demographics, comorbidities, imaging of the carotid arteries, and prospective events, such as stroke, myocardial infarction (MI), and death, were recorded. Time to first stroke, first MI, and death was estimated using Kaplan-Meier estimation separately and as a composite end point.

RESULTS

There were 221 patients identified with a confirmed diagnosis of RAO. The mean age in the cohort was 66.1 years; 53% of patients were male, and 29% were diabetic. Median length of follow-up was 2.2 years. Five patients (2.3%) had a documented stroke; four of the five strokes occurred at the time of RAO, with one that was contralateral occurring at 1.2 years. There were eight MIs (3.6%) in the cohort, two of which resulted in death. Twenty-two patients (10%) experienced a stroke, MI, or death. There were 141 (63.8%) patients who had carotid imaging performed, of whom 20 (14.2%) were found to have >50% stenosis.

CONCLUSIONS

The rate of stroke in patients with confirmed RAO was 2.3%; however, excluding concurrent ischemic events, the risk was <1%. The incidence of carotid artery stenosis >50% was 14.2%. The authors conclude that the risk of stroke after confirmed RAO is lower than previously reported and comparable to prior population-based studies of all at-risk adults.

Comparing the Superficial Vasculature of the Central Nervous System in Six Laboratory Animals: A Hypothesis About the Role of the "Circle of Willis"

We provide images of the entire central nervous system vasculature, and compare the anatomical findings in six different laboratory animals. A detailed understanding of the specific anatomy for each is important in the design of experimental modeling and for understanding the specific function of each target organ. Six different types of animals, the Korean wild mouse, C57BL/6J mouse, F344 rat, mongolian gerbil, Syrian hamsters, and guinea pigs, were included. To stain the blood vessels in each of the animals, Alcian blue reagent was used to perfuse each species. The bifurcation and anastomotic patterns of the anterior cerebral arteries differed in each species. The vascular supply to the olfactory nerve was visualized as a single artery supplying both olfactory nerves, and arteries supplying the lateral portion of the olfactory nerves originating from the olfactory bulb area. The posterior communicating arteries of the six animals demonstrated unique morphologies. The shape of the hypophyseal portal system varied by species. Most animals used in this study had a hexagonal Circle of Willis, except for the Korean wild mouse. Using this approach, we successfully mapped the brain vascular system in six different species of animals. This information and the images created can guide other researchers as they design research studies and create experimental models for new surgical procedures and approaches. Anat Rec, 2019. © 2019 Wiley Periodicals, Inc. Anat Rec, 302:2049-2061, 2019. © 2019 American Association for Anatomy.

Treatment of Nonarteritic Acute Central Retinal Artery Occlusion

Central retinal artery occlusion (CRAO) is an event most often caused by an embolus originating in the ipsilateral carotid artery, aortic arch, or heart. CRAO may result from partial or complete occlusion of the central retinal artery (CRA), which acts as the primary blood supply to the inner neurosensory retina, and typically results in profound vision loss and permanent visual disability. No consensus has emerged regarding the optimal treatment of CRAO. All proposed treatments are of questionable efficacy and many have uncertain risk profiles. In certain circumstances, thrombolysis may be attempted as a treatment option; however, the evidence to support broad use of thrombolytics in the treatment of acute CRAO remains elusive. It is known that the risk factors that predispose to other cardiovascular and cerebrovascular events are often present in CRAO. Accordingly, identification of patients at highest risk of stroke and secondary prevention of ischemic events remains the primary focus of management. This review offers a summary of the clinical presentation, diagnosis, and prognosis of CRAO, with an emphasis on treatment options.

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.

Clinical Analysis of 42 Cases of Ocular Ischemic Syndrome

Ocular ischemic syndrome (OIS) is a severe ocular disease caused by ocular hypoperfusion due to stenosis or occlusion of the common or internal carotid arteries. OIS is easily misdiagnosed or undiagnosed given its asymptomatic onset and complicated ocular manifestations. The present study reviewed 42 patients with OIS, including 30 males (71.43%), 29 older patients (69.05%, >61 yrs), and 35 patients (83.33%) with two or more systemic diseases. Only 6 patients had ocular symptoms as the initial signs upon visiting the Department of Ophthalmology of three hospitals (the First Affiliated Hospital, Sun Yat-sen University; Zhongshan Ophthalmic Center, Sun Yat-sen University; and the Second Affiliated Hospital, Guangzhou Medical University). The ocular symptoms varied from visual deterioration to periorbital pain. Thirty-seven patients (88.10%) complained of constitutional symptoms. Ocular manifestations were diverse and involved both anterior and posterior segments. We reported a case of corneal edema and corneal epithelium erosion in the ipsilateral eye due to internal carotid artery stenosis. As the clinical manifestations of OIS are complex, ophthalmologists must carefully examine patients to avoid a misdiagnosis or a failure to diagnose. The management of OIS requires cooperation with cardiologists and neurologists.