Local intraarterial fibrinolysis administered in aliquots for the treatment of central retinal artery occlusion: the Johns Hopkins Hospital experience

A Remote Consult Retinal Artery Occlusion Diagnostic Protocol

PURPOSE

To report a novel protocol for diagnosis of retinal artery occlusions at the point of care using OCT and a remote consult model.

DESIGN

Retrospective case series and evaluation of a diagnostic test or technology.

PARTICIPANTS

Adult patients who presented with painless monocular vision loss and were diagnosed with a nonarteritic retinal artery occlusion.

METHODS

OCT machines were placed in the stroke center or emergency department at 3 hospitals within our health system. Patients who presented with painless monocular vision loss were evaluated by the stroke neurology service and an OCT was acquired. The images were interpreted remotely by the retina service. An in-house ophthalmology consult was not required to make the final treatment decision. Eligible patients were treated with intra-arterial tissue plasminogen activator (IA-tPA). Patients were followed by ophthalmology during their admission when an in-house consultation service was available or otherwise evaluated immediately after discharge.

MAIN OUTCOME MEASURES

Visual acuity (VA) before and after treatment with IA-tPA; time from last known well (LKW) to treatment; and time from presentation to treatment.

RESULTS

In the first 18 months since the protocol went live, 59 patients were evaluated. Twenty-five patients (42%) had a confirmed retinal artery occlusion based on OCT and follow-up examination. Ten patients were eligible for treatment, and 9 patients received treatment with IA-tPA. There was a statistically significant improvement in mean VA from logarithm of the minimum angle of resolution (logMAR) 2.14 to logMAR 0.7 within 24 hours after treatment (P = 0.0001) and logMAR 1.04 after 4 weeks (P = 0.01). Clinically significant improvement was noted in 66% of patients within 24 hours and maintained through 1 month in 56% of all treated patients. The mean time to treatment from LKW was 543 minutes and from presentation at the stroke center was 146 minutes.

CONCLUSIONS

We report the successful implementation of a remote consult protocol using point-of-care automated OCT. This novel paradigm demonstrates the potential utility of remote consult services for the diagnosis of time-sensitive ophthalmic emergencies.

FINANCIAL DISCLOSURE(S)

Proprietary or commercial disclosure may be found after the references.

Retinal arterial and vein occlusion: is surgery ever indicated?

PURPOSE OF REVIEW

To highlight the recent progression in surgical treatments for central retinal vein occlusion (CRVO) and central retinal artery occlusion (CRAO).

RECENT FINDINGS

Anti-VEGF treatment, accepted as a primary treatment for CRVO, is unable to effectively treat all types of the diseases. Regarding CRAO, there are not any accepted therapies available. There have however been recent innovations in surgery, such as utilizing robotics-assisted tools in cannulation procedures for central retinal artery occlusion, or micro-cystotomy for refractory macular edema resulting from ischemic CRVO.

SUMMARY

Refractory macular edema due to CRVO can be treated with aspiration of the fluid found inside the large cysts often seen in edema. The success rate of micro-cystotomy has been reported at 78% in eyes with refractory macular edema. Recent studies have shown that cannulation with tissue plasminogen activator (tPA) is effective for eyes with CRAO due to thrombus.Recent cannulation or micro-cystotomy procedures can be enhanced with the use of robotic tools which allow us to perform this difficult procedure more easily. Newly developed technology, and consequent developments in surgical procedures, will allow us to deal with unmet needs for retinal vessel occlusive diseases.

Improved visual outcomes of central retinal artery occlusion with local intra-arterial fibrinolysis beyond the conventional time window

Local intra-arterial fibrinolysis (LIF) is a promising therapeutic option for CRAO. However, the narrow time window of 6 h has greatly limited the application of LIF. In this study, we explored the efficacy of LIF beyond the conventional time windows and compared the result with conservative therapy. This prospective study included 179 CRAO patients with baseline visual acuity (VA) ≤ 20/400 treated at Renmin Hospital of Wuhan University. The mean time from vision loss to presentation was 5.5 days. 58 patients received conventional standard therapy (CST) alone.121 patients underwent LIF. Main outcome was VA improvement ≥ 0.3 logMAR. Secondary outcome was a favorable VA outcome of 20/200 or better. Logistic regressions were performed to identify predictors of visual improvement. 43% patients in the LIF group experienced VA improvement versus 19% with CST (P = 0.002). LIF was associated with 4.0-fold higher likelihood of visual improvement compared to CST (P = 0.001). Poor baseline VA (light perception or no light perception) and shortened prothrombin time (PT) were associated with greater chance of visual improvement with LIF. However, LIF showed no significant advantage over CST for favorable VA outcomes. No major complications occurred. LIF beyond the therapeutic time window improved vision in functionally blind CRAO patients and showed better efficacy when compared with CST. PT may be a potential predictor of visual outcome after LIF. Our findings could complement existing time-based treatment guidelines and potentially allow for personalized decisions on the use of LIF beyond time windows.

Network Meta-Analysis of Different Thrombolytic Strategies for the Treatment of Central Retinal Artery Occlusion

PURPOSE

Intravenous and intra-arterial thrombolytic strategies have been used to treat central retinal artery occlusion (CRAO); however, previous meta-analyses evaluated the efficacy of these two thrombolytic strategies separately but did not compare them. This network meta-analysis aimed to evaluate the comparative efficacy and safety of different thrombolytic methods for treating CRAO.

METHODS

We searched PubMed, Embase, the Cochrane Library, China National Knowledge Infrastructure (CNKI), and Wanfangdata to identify relevant studies published before 1 January 2023. We used the "network" command in STATA 14.0 software to perform network meta-analysis. In addition, we calculated the surface under the cumulative ranking (SUCRA) to rank all currently available thrombolytic strategies.

RESULTS

We included 12 studies in the final data analysis. Results suggested that, compared with standard treatment (ST), intravenous tissue plasminogen activator (IVtPA) (OR, 5.78; 95% CI, 2.07 to 16.11) and intra-arterial urokinase (IAUK) (OR, 2.78; 95% CI, 1.10 to 7.02) and intra-arterial tPA (IAtPA) (OR, 2.45; 95% CI, 1.04 to 5.77) achieved better visual improvement. The differences in visual improvement among IVtPA, IAUK, and IAtPA are insignificant. Furthermore, compared with ST, administration of IVtPA within 4.5 hours of CRAO onset (OR, 8.87; 95% CI, 3.35 to 23.48) rather than administration after 4.5 hours of onset (OR, 3.09; 95% CI, 0.81 to 11.70) achieved better visual improvement. In addition, compared to ST, all available thrombolytic strategies we evaluated were associated with a higher risk of adverse events, but these strategies did not differ. Based on the results of SUCRA, IVtPA had the highest ranking probability in visual improvement (91.9%) but had a relatively lower ranking probability of adverse events (60.1%).

CONCLUSION

Both intravenous and intra-arterial thrombolytic strategies are effective for treating CRAO, but SUCRA results show that IVtPA may be the optimal strategy for treating CRAO. Furthermore, based on the results of subgroup analysis, we further speculate that IVtPA injection within 4.5 hours of the onset of CRAO should be the optimal thrombolytic option for treating CRAO. However, due to the limitations of all eligible studies, more studies are still required in the future to validate our findings.

Thrombolysis for central retinal artery occlusion: An individual participant-level meta-analysis

BACKGROUND

Whether thrombolysis improves outcomes in non-arteritic central retinal artery occlusion (naCRAO) is uncertain. We aimed to evaluate the rate of visual recovery after intra-venous thrombolysis (IVT) or intra-arterial thrombolysis (IAT) administration of tissue plasminogen activator (tPA) or urokinase among patients with naCRAO and explore the parameters affecting the final visual acuity (VA).

AIM

We systematically searched six databases. Logarithm of the minimum angle of resolution (logMAR) and VA of ⩾20/100 were used to quantify visual recovery. To explore the role of other factors on visual recovery, we defined two models for studies with aggregated data (designs 1 and 2) and 16 models for individual participant data (IPD, models 1-16).

SUMMARY OF REVIEW

We included data from 771 patients out of 72 publications in nine languages. Visual improvement for ⩾0.3 logMAR was reported in 74.3% of patients who received IVT-tPA within 4.5 h (CI: 60.9-86.0%; unadjusted rate: 73.2%) and 60.0% of those who received IAT-tPA within 24 h (CI: 49.1-70.5%; unadjusted rate: 59.6%). VA of ⩾20/100 was observed among 39.0% of patients after IVT-tPA within 4.5 h and 21.9% of those with IAT-tPA within 24 h. IPD models highlighted the association between improved visual outcomes and VA at presentation, at least 2 weeks follow-up before reporting the final VA, antiplatelet therapy, and shorter symptom onset to thrombolysis window.

CONCLUSION

Early thrombolytic therapy with tPA is associated with enhanced visual recovery in naCRAO. Future studies should refine the optimum time window for thrombolysis in naCRAO.

Progress in central retinal artery occlusion: a narrative review

Central retinal artery occlusion (CRAO) is a catastrophic ophthalmic emergency that severely impairs a patient's visual function, often reducing visual acuity to counting fingers or worse. Progress in CRAO research has provided new information regarding its epidemiological characteristics and led to useful assessments through various ophthalmic examinations. Additional insights about CRAO have been gained through studies of its pathophysiological mechanisms, improving intervention timing and enhancing patient prognosis. Treatment for CRAO has evolved, particularly with assistance from surgical instruments and surgical robots. Although surgical treatment is now possible, this option is not widely recognized by ophthalmologists. Conservative therapies have limited benefits compared with the natural course of disease. Recently, pars plana vitrectomy plus endovascular surgery has received considerable interest among ophthalmologists because of its potential efficacy in the treatment of CRAO. Considering the inconsistencies in rationale and efficacy of CRAO treatment modalities, it is important to distinguish between treatment effects and the natural courses of various CRAO subclasses. This narrative review explores progress in CRAO epidemiology, pathophysiology, ophthalmic examination, and treatment.

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.

Efficacy and safety of intra-arterial thrombolysis in patients with central retinal artery occlusion: a systematic review and meta-analysis

PURPOSE

To investigate the efficacy and safety of intra-arterial thrombolysis (IAT) in patients with central retinal artery occlusion (CRAO).

METHODS

PubMed and EMBASE were searched for potentially eligible studies that reported IAT in CRAO patients from inception to Nov 8, 2021. Standard mean difference (SMD) was pooled to compare visual acuity (VA) at baseline with final in IAT patients. The rates and odds ratios (OR) were meta-analyzed to compare VA improvement in IAT with non-IAT patients, stratified to different times from onset to procedure, different definitions of VA improvement, and three CRAO stages. Adverse effects were recorded.

RESULTS

Fifteen studies were included, enrolling 507 CRAO patients who received IAT and 296 CRAO patients who did not. VA was significantly improved from baseline to final VA in IAT patients (SMD [LogMAR] 0.70, 95% CI [0.51, 0.90]). VA improvement rate was higher in IAT patients than that in non-IAT (56% vs 32%, OR 3.55, 95%CI [1.74, 7.24]), with greater OR in IAT within 6 h from onset to procedure (OR 4.60, 95%CI [1.24, 16.99]) than that beyond 6 h (OR 3.36, 95%CI [1.43, 7.85]). The benefit remained consistent when VA improvement was defined as ≥ 3 lines on the Snellen chart (OR 4.68, 95%CI [2.10, 10.41]) and was even greater when CRAO was incomplete. Five patients had a symptomatic intracranial hemorrhage and 21 patients had ischemic stroke or transient ischemic attack after IAT.

CONCLUSIONS

IAT treatment has certain potential in ameliorating VA in CRAO patients, which should be balanced against cerebral complications.

A review of the management of central retinal artery occlusion

Central retinal artery occlusion (CRAO), the ocular analog of a cerebral stroke, is an ophthalmic emergency. The visual prognosis for overall spontaneous visual recovery in CRAO is low. Furthermore, the risk of future ischemic heart disease and cerebral stroke is increased due to the underlying atherosclerotic risk factors. There is currently no guideline-endorsed treatment for CRAO. This review will describe the anatomy, pathophysiology, epidemiology, and clinical features of CRAO, and investigate the current and future management strategies.

Efficacy of Intra-Arterial Thrombolysis for Acute Central Retinal Artery Occlusion: A Meta-Analysis

INTRODUCTION

The best management strategy still remains strong controversy for acute nonarteritic central retinal artery occlusion (CRAO). We thus performed a meta-analysis to determine the efficacy of intra-arterial thrombolysis (IAT) for visual improvement according to different times from symptom onset.

METHODS

We searched EMBASE, PubMed, and Web of Science for relevant studies assessing efficiency of IAT in patients with CRAO compared with standard therapy. Fixed-effects and random-effects models were performed.

RESULTS

Five eligible studies including 459 patients with acute CRAO were pooled in the meta-analysis. In all, 219 (47.7%) received IAT, and the mean time from symptom onset to IAT was 13 h. The pooled analysis demonstrates odds ratio (OR) for the procedure of IAT and any visual improvement to be 1.520 (95% confidence intervals [CIs] 1.258-1.837; p < 0.001). Subgroup analyses further indicated that the CRAO patients who received IAT achieved any visual improvement more easily within 6 h from symptom onset (OR = 1.703, 95% CI 1.219-2.381; p = 0.002), but not those beyond 6 h (OR = 1.260, 95% CI 0.973-1.632; p = 0.080).

CONCLUSION

Our meta-analysis of available published data supports IAT to be an alternative treatment option for CRAO patients within 6 h from symptom onset.

Hyperbaric Oxygen Therapy for Central Retinal Artery Occlusion: Patient Selection and Perspectives

The central retinal artery occlusion (CRAO) is a rare ophthalmological emergency that can occur in the eye. CRAO can affect persons of any age, however it is most common in people over the age of 60. CRAO is associated with a number of risk factors, including giant cell arteritis, carotid artery atherosclerosis, cardiogenic emboli, hypertension, smoking, diabetes, and thromboembolic disease. The chance of each of these etiologies being present is assessed during the course of the investigation. Hyperbaric oxygen treatment (HBOT) is classified by the American Heart Association for CRAO at level IIb. In accordance with that, HBOT might be considered for the treatment of such a severe condition. HBOT can maintain retinal oxygenation during ischemic events by allowing oxygen to diffuse through choroidal capillaries that have been exposed to elevated partial pressures of oxygen. As a result, ischemia-related damage is reversed if applied within proper time frame. The amount of time that has passed prior to initiation of HBOT is considered to be the most critical factor in determining the best visual prognosis. According to the Undersea and Hyperbaric Medical Society, patients who are identified with CRAO after the onset of symptoms should be evaluated for HBOT within 24 hours. HBOT has the advantage of having a low risk profile, and it can be utilized to improve visual outcomes in proper patients.

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.

The actual role of thrombolytic treatment in central retinal artery occlusion

OBJECTIVE

The purpose of this study is to determine the application of thrombolytic treatment in central retinal artery occlusion (CRAO), its real benefit, safety and possible indications for treatment.

METHODS

We searched the PubMed, Cochrane and Google Scholar databases delving first into the effectiveness of the traditional treatment for CRAO, and then comparing them with new treatment strategies with intra venous or intra arterial fibrinolysis.

RESULTS

Whereas small retrospective and open-label observational trials support the use of thrombolytic therapy, multicenter randomized trials failed to demonstrate a significant visual improvement with this new strategy. Besides that, a greater risk of life threatening adverse event was observed in patients using thrombolytic treatment.

CONCLUSION

Until well-conducted clinical trials demonstrate a clear benefit of thrombolytic therapy for improving visual acuity and their benefit are weighted against the frequency and severity of adverse events, we could not recommend fibrinolysis for treating CRAO.

Intra-Arterial Tissue Plasminogen Activator for Central Retinal Artery Occlusion

Purpose

To investigate the benefit of early intra-arterial tissue plasminogen activator (IAT) for treatment of central retinal artery occlusion (CRAO).

Patients and Methods

Fifteen eyes of 15 patients presenting with acute CRAO were included in this retrospective consecutive interventional case series. Patients were excluded if treatment with IAT was not initiated within 12 hours. The diagnosis was confirmed by an ophthalmologist. IAT was performed via a transfemoral arterial approach. Tissue plasminogen activator (tPA) was infused into the ophthalmic artery in aliquots up to 3mg to a maximum of 22mg. Paracentesis was done at the ophthalmologist's discretion. The primary outcome measure was visual acuity after three weeks. Adverse events were recorded during treatment and follow-up visits.

Results

After treatment with IAT, there was a statistically significant improvement in visual acuity, with a mean change of -0.76 (SD 0.91; range -2.4 to 0.85) logMAR (p=0.006). Vision improved by 3 or more lines in 53%, and of these, the mean Snellen visual acuity improvement was >6 lines. Notably, 4 patients (27%) improved from CF or worse to 20/80 or better. The mean dose of tPA used was 17mg and the mean time to treatment was 8.83 hours (range: 5.5 to 12 hours). There were no statistically significant differences based on time to treatment, dose of tPA, or use of a paracentesis. No major adverse events were recorded.

Conclusion

IAT was safe and showed significant visual improvement in this small uncontrolled study. Larger studies and efforts to decrease time to treatment should be initiated to optimize outcomes.

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.

Management of Acute Central Retinal Artery Occlusion, a "Retinal Stroke": An Institutional Series and Literature Review

OBJECTIVES

Acute central retinal artery occlusion (CRAO) is an ophthalmologic emergency that often results in permanent vision loss. Over 25% are associated with acute cerebral ischemia. In the absence of existing Level I treatment options, this study aims to examine institutional practice patterns and review the literature to develop a formalized approach to the treatment of CRAO in the era of ischemic stroke protocols.

MATERIALS AND METHODS

This is a retrospective review of institutional practices in the workup and treatment of patients diagnosed with acute non-arteritic (NA) CRAO at a single center from January 2017 to August 2020.

RESULTS

Of 91 patients managed for acute NA-CRAO, 62.6% were male and average age was 66.4 years. Only 20.9% of patients presented within 4 h of symptom onset. 12.1% of patients had evidence of acute stroke on MRI, and 27.5% had ipsilateral internal carotid artery stenosis >50%. Half (52.7%) did not receive any acute treatment for CRAO, excluding antiplatelet/anticoagulation. 48.5% of patients undergoing acute medical treatment had improved visual acuity compared to 29.4% without treatment (p=0.14).

CONCLUSIONS

There is a lack of clear protocol for the management of NA-CRAO. While not reaching statistical significance, our experience mirrors the literature with patients undergoing medical treatment demonstrating improved visual acuity over those without treatment. Given the presence of acute ischemic stroke, carotid disease, and/or stroke risk factors in over 25% of patients with CRAO, multidisciplinary involvement and modern stroke algorithms should be considered for this disease.

Ophthalmology in Critical Care

Ophthalmic disease encountered in the intensive care unit (ICU) has a wide spectrum of prevalence and severity. Prolonged exposure of the cornea is common and preventable. Trauma, glaucoma, infection, vascular disease, and burns are among the potential causes of vision loss. Patients are predisposed to ocular complications by the ICU environment and critical illness itself. Critically ill patients require prioritization of life-sustaining interventions, and less emphasis is placed on ophthalmic disease, leading to missed opportunities for vision-saving intervention. It is therefore imperative for intensivists, nurses, and other providers to have an increased awareness and understanding of the broad range of ocular conditions potentially seen in the ICU.

Paracentral Acute Middle Maculopathy as a Presenting Sign of CRAO in Sickle Cell Disease Treated with Tissue Plasminogen Activator

PURPOSE

We report the case of a 27-year-old monocular woman with history of sickle cell disease who received intra-arterial tissue plasminogen activator (tPA) after presenting with acute painless vision loss secondary to incomplete central retinal artery occlusion presenting as paracentral acute middle maculopathy (PAMM) in her left eye.

METHODS

Ultra-widefield fundus photography, ultra-widefield fluorescein angiography, en face ocular coherence tomography (OCT), and ocular coherence tomography angiography (OCTA) were obtained and reviewed, followed by cerebral angiography and infusion of intra-arterial tissue plasminogen activator (tPA).

RESULTS

A patient with a history of sickle cell disease presented with new onset of a dense central scotoma and visual acuity diminished to 20/200 from baseline 20/20 in her left eye. Fluorescein angiogram was non-diagnostic. OCT revealed perifoveal hyperreflective bands in the inner nuclear layer in a pattern characteristic of PAMM. The patient received intra-arterial tPA through her left ophthalmic artery shortly after presentation, resulting in a gradual restoration of visual acuity to 20/20 in the three months following the procedure.

CONCLUSIONS

This is the first report describing the use of intra-arterial tPA to treat incomplete central retinal artery occlusion presenting as a PAMM lesion in a patient with sickle cell disease.

Dramatic recovery of vision in patient with acute central retinal artery occlusion treated with local intra-arterial tissue plasminogen activator

Central retinal artery occlusion (CRAO) is a devastating disease resulting in severe visual loss in most cases. It has no proven treatment, and a variety of management options used clinically all have dismal rate of success. We report outcome of treatment with local intra-arterial thrombolysis administered 2.75 hours after devastating visual loss from incomplete CRAO.

Iatrogenic ophthalmic artery occlusion and retinal artery occlusion

Iatrogenic ophthalmic artery occlusion (IOAO) is a rare but devastating ophthalmic disease that may cause sudden and permanent visual loss. Understanding the possible etiologic modalities and pathogenic mechanisms of IOAO may prevent its occurrence. There are numerous medical etiologies of IOAO, including cosmetic facial filler injection, intravascular procedures, intravitreal gas or drug injection, retrobulbar anesthesia, intraarterial chemotherapy in retinoblastoma. Non-ocular surgeries and vascular events in arteries that are not directly associated with the ophthalmic artery, can also cause IOAO. Since IOAO has a limited number of treatment modalities, which lead to poor final visual prognosis, it is imperative to acknowledge the information regarding medical procedures that are etiologically associated with IOAO. We accumulated all searchable and available IOAO case reports (our cases and previous reported cases from the literature), classified them according to their mechanisms of pathogenesis, and summarized treatment options and responses of each of the causes. Various sporadic cases of IOAO can be categorized into three mechanisms as follows: intravascular event, orbital compartment syndrome, and increased intraocular pressure. Embolic IOAO, which is considered the primary cause of the condition, was classified into three subgroups according to the pathway of embolic movement (retrograde pathway, anterograde pathway, pathway through collateral channels). Despite the practical limitations of treating spontaneous (non-iatrogenic) retinal artery occlusion, this article will contribute in predicting and improving the prognosis of IOAO by recognizing the treatable factors. Furthermore, it is expected to provide clues to future research associated with the treatment of retinal artery occlusion.

Characteristics and Outcomes of Retinal Artery Occlusion: Nationally Representative Data

Background and Purpose- There are few large studies examining comorbidities, outcomes, and acute interventions for patients with retinal artery occlusion (RAO). RAO shares pathophysiology with acute ischemic stroke (AIS); direct comparison may inform emergent treatment, evaluation, and secondary prevention. Methods- The National Readmissions Database contains data on ≈50% of US hospitalizations from 2013 to 2015. We used International Classification of Diseases, Ninth Revision, codes to identify and compare index RAO and AIS admissions, comorbidities, and interventions and Clinical Comorbidity Software codes to identify readmissions causes, using survey-weighted methods when possible. Cumulative risk of all-cause readmission after RAO ≤1 year was estimated by Kaplan-Meier analysis. Results- Among 4871 RAO and 1 239 963 AIS admissions, patients with RAO were less likely (P<0.0001) than patients with AIS to have diabetes mellitus (RAO, 24.3% versus AIS, 36.8%), congestive heart failure (9.1% versus 14.8%), atrial fibrillation (15.5% versus 25.2%), or hypertension (62.2% versus 67.6%) but more likely to have valvular disease (13.3% versus 10.5%) and tobacco usage (38.6% versus 32.9%). In RAO admissions, thrombolysis was administered in 2.9% (5.8% in central RAO subgroup, versus 8.0% of AIS), therapeutic anterior chamber paracentesis in 1.0%, thrombectomy in none; 1.4% received carotid endarterectomy during index admission, 1.6% within 30 days. Nearly 1 in 10 patients with RAO were readmitted within 30 days and were more than twice as likely as patients with AIS to be readmitted for dysrhythmia or endocarditis. Readmission for stroke after RAO was the highest within the first 150 days after index admission, and risk was higher in central RAO than in branch RAO. Conclusions- Patients with RAO had high prevalence of many stroke risk factors, particularly valvular disease and smoking, which can be addressed to minimize subsequent risk. Despite less baseline atrial fibrillation, RAO patients were more likely to be readmitted for atrial fibrillation/dysrhythmias. A variety of interventions was administered. AIS risk is the highest shortly after RAO, emphasizing the importance of urgent, thorough neurovascular evaluation.

Intra-Arterial Thrombolysis for Central Retinal Artery Occlusion

Introduction

Central retinal artery occlusion is an ophthalmic emergency which typically causes acute, painless visual loss. Several conservative treatment options are practiced with little benefit. Thrombolysis as a therapeutic option has gathered interest as well as controversy. This paper aims at reviewing the relevant literature to assess the efficacy and safety of intra-arterial thrombolysis for acute central retinal artery occlusion.

Methods

A review of the literature was conducted. Keywords included “intra-arterial thrombolysis” or “intra-arterial fibrinolysis” in combination with “central retinal artery occlusion” or “CRAO”. A Cochrane Database search was performed for randomised control trials, systematic reviews and meta-analyses using the same keywords.

Results

Twenty-eight studies were identified which included case reports, case series, case-control studies and 1 randomised control trial: the European Assessment Group for Lysis in the Eye Study. Improvement in vision was measured using different methods and at different time points. The findings of these studies generally favour an effect towards intra-arterial thrombolysis however there are many limitations. Additionally, the European Assessment Group for Lysis in the Eye Study showed lack of effect in intra-arterial thrombolysis vs conservative measures.

Conclusion

Current evidence is not sufficient to recommend intra-arterial thrombolysis due to the variability of visual improvement within retrospective studies, heterogeneity in treatment regimens between studies and adverse effects. Intra-arterial thrombolysis may have a role in patients presenting early, particularly if they have monocular vision, after discussion of the risks and benefits. Further high-quality trials assessing the clinical efficacy of intra-arterial thrombolysis may shed more light on this topic.

New concepts on acute ocular ischemia

PURPOSE OF REVIEW

To review recent advances in the management of acute ocular ischemic events, including: transient monocular vision loss, central and branch retinal artery occlusions, and nonarteritic anterior ischemic optic neuropathy.

RECENT FINDINGS

Transient monocular vision loss and acute retinal arterial occlusions require immediate diagnosis and management, with recognition of these events as transient ischemic attack or stroke equivalents, respectively. Patients should undergo an immediate stroke workup in a stroke center, similar to patients with acute cerebral ischemia. The treatment of central retinal artery occlusions remains limited despite the growing use of thrombolytic treatments. The indication for these treatments remains under debate. No quality evidence exists to support any therapy, including corticosteroids, in the treatment of nonarteritic anterior ischemic optic neuropathy. The highest priority in management is to rule-out giant cell arteritis.

SUMMARY

Effective therapies for the treatment of ischemic events of the retina and optic nerve remain elusive. Clinicians should focus on the prompt recognition of these events as ocular emergencies and immediately refer patients with vascular transient visual loss and acute central and branch retinal arterial occlusions to the nearest stroke center.

Central Retinal Artery Occlusion Associated with Carotid Artery Occlusion

Sudden, painless vision loss in patients with stroke risk factors is suspect for central retinal artery occlusion (CRAO), an ophthalmic emergency that in addition to ocular treatment warrants a thorough neurologic and vascular evaluation. In addition to the high risk of concurrent stroke, carotid artery stenosis and occlusion is often overlooked during the initial evaluation. Here we report a case of CRAO with concurrent ipsilateral complete left internal carotid artery (ICA) occlusion and right ICA critical narrowing, dissection and pseudoaneurysm, which subsequently improved with prompt hyperbaric oxygen therapy.

Central retinal artery occlusion-A new, provisional treatment approach

The retinal ganglion cells infarcted in central retinal artery occlusion (CRAO) are the somata of the optic nerve axons, part of the central nervous system. Consequently, CRAO with inner retinal infarction is a small vessel stroke, usually with the devastating consequence of severe visual loss in the affected eye. At present, there is no generally accepted, evidence-based therapy of nonarteritic CRAO in contrast to ischemic cerebral stroke that has well-accepted treatment protocols. Widely divergent and controversial therapeutic options for CRAO reflect the desperation of treating physicians and disparate conflicting studies. We examine reasons why treatment of nonarteritic CRAO remains problematic and then suggest a provisional new approach to treatment based on updated understanding of CRAO pathophysiology and analysis of current therapeutic options and their rationales.

Central retinal artery occlusion

The pathogeneses, clinical features, and management of central retinal artery occlusion (CRAO) are discussed. CRAO consists of the following four distinct clinical entities: non-arteritic CRAO (NA-CRAO), transient NA-CRAO, NA-CRAO with cilioretinal artery sparing, and arteritic CRAO. Clinical characteristics, visual outcome, and management very much depend upon the type of CRAO. Contrary to the prevalent belief, spontaneous improvement in both visual acuity and visual fields does occur, mainly during the first 7 days. The incidence of spontaneous visual acuity improvement during the first 7 days differs significantly (P < 0.001) among the four types of CRAO; among them, in eyes with initial visual acuity of counting finger or worse, visual acuity improved, remained stable, or deteriorated in NA-CRAO in 22%, 66%, and 12%, respectively; in NA-CRAO with cilioretinal artery sparing in 67%, 33%, and none, respectively; and in transient NA-CRAO in 82%, 18%, and none, respectively. Arteritic CRAO shows no change. Recent studies have shown that administration of local intra-arterial thrombolytic agent not only has no beneficial effect but also can be harmful. Investigations to find the cause and to prevent or reduce the risk of any further visual problems are discussed. Prevalent multiple misconceptions on CRAO are discussed.

Is Management of Central Retinal Artery Occlusion the Next Frontier in Cerebrovascular Diseases?

Central retinal artery occlusion (CRAO) is a medical emergency that, if not treated, may result in irreversible loss of vision. It continues to be an important cause for acute painless loss of vision. Amaurosis fugax or "transient CRAO" has long been considered an equivalent of transient cerebral ischemic event. Animal models, in addition to data from retrospective and randomized clinical studies, provide valuable insights into the time interval for irreversible retinal ischemia. Subset analyses from 2 large studies of patients with CRAO show benefit from treatment with thrombolysis within 6 hours from symptoms onset. Significant workflow improvements after the intra-arterial therapy trials for acute ischemic stroke have occurred world over in last 5 years. Patients with CRAO are uniquely suited to receive maximum benefits from the changes in workflow for treatment of patient's acute ischemic stroke. Just as in clinical triage of acute ischemic stroke, correct and timely diagnosis of patients with CRAO may help in preventing visual loss. The approach to acute ocular ischemia should mimic that used for acute brain ischemia. Comprehensive stroke centers would be ideal triage centers for these patients in view of availability of multidisciplinary participation from vascular neurology, neuroendovascular surgery, and ophthalmology. Time is Retina!

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.

Central retinal artery occlusion - rethinking retinal survival time

Background

The critical time from onset of complete occlusion of the central retinal artery (CRA) to functionally significant inner retinal infarction represents a window of opportunity for treatment and also has medical-legal implications, particularly when central retinal artery occlusion (CRAO) complicates therapeutic interventions. Here, we review the evidence for time to infarction from complete CRAO and discuss the implications of our findings.

Methods

A Medline search was performed using each of the terms “central retinal artery occlusion”, “retinal infarction”, “retinal ischemia”, and “cherry red spot” from 1970 to the present including articles in French and German. All retrieved references as well as their reference lists were screened for relevance. An Internet search using these terms was also performed to look for additional references.

Results

We find that the experimental evidence showing that inner retinal infarction occurs after 90–240 min of total CRAO, which is the interval generally accepted in the medical literature and practice guidelines, is flawed in important ways. Moreover, the retinal ganglion cells, supplied by the CRA, are part of the central nervous system which undergoes infarction after non-perfusion of 12–15 min or less.

Conclusions

Retinal infarction is most likely to occur after only 12–15 min of complete CRAO. This helps to explain why therapeutic maneuvers for CRAO are often ineffective. Nevertheless, many CRAOs are incomplete and may benefit from therapy after longer intervals. To try to avoid retinal infarcton from inadvertent ocular compression by a headrest during prone anesthesia, the eyes should be checked at intervals of less than 15′.

Intra-Arterial Thrombolysis for Acute Central Retinal Artery Occlusion: A Systematic Review and Meta-Analysis

Background and purpose

Acute central retinal artery occlusion (CRAO) is a serious ophthalmologic emergency that may result in monocular blindness. To date, studies evaluating intra-arterial thrombolysis (IAT) have not shown a definitive clinical benefit. We have conducted a systematic review with a meta-analysis to effectively evaluate this treatment option.

Methods

A systematic literature search was focused on studies containing five or more patients undergoing IAT that included a control group treated with standard therapy. Pooled meta-analysis was performed.

Results

Five retrospective controlled studies and one randomized clinical trial were identified satisfying all inclusion criteria resulting in the analysis of 236 patients treated with IAT and 255 patients treated with ST. A pooled fixed effects analysis resulted in an estimated odds ratio of 2.52, 95% CI (1.69, 3.77) (P < 0.0001) favoring IAT.

Conclusion

IAT is a promising therapeutic option for CRAO with great potential. Further randomized trials are needed to establish a significant benefit and ensure the safety of the intervention.

Reversal of cilioretinal artery occlusion with intra-arterial tissue plasminogen activator

Purpose

To present the reversal of a cilioretinal artery occlusion with the use of intra-arterial tissue plasminogen activator.

Observations

A monocular 74 year old male presented with a cilioretinal artery occlusion. Treatment with intra-arterial tissue plasminogen activator 7 hours after the onset of symptoms led to a complete restoration of vision.

Conclusions and importance

Early intervention with tissue plasminogen activator reversed acute onset loss of vision from cilioretinal artery occlusion.

New Standards of Care in Ischemic Stroke

BACKGROUND

Ischemic arterial strokes of the ophthalmic artery and its branches and posterior cerebral artery are common causes of visual disability. Etiologies of stroke affecting the retina, optic nerve, optic radiation, and visual cortex overlap with other types of ischemic strokes. Stenosis of the internal carotid is the most common cause of central retinal artery occlusion (CRAO). One-fourth of patients with CRAO have cerebral strokes. We report recent developments in the acute treatment and secondary prevention of ischemic stroke of relevance to clinicians who encounter patients with acute vision loss.

EVIDENCE ACQUISITION

A search of Pubmed and practice guidelines over the past 5 years was performed, with a focus on significant changes in treatment and prevention of ischemic stroke.

RESULTS

Recent randomized controlled trials provide Level I evidence for the use of endovascular therapy with current stent retriever devices for patients with large vessel anterior circulation occlusions within 6 hours of presentation. Number needed to treat to achieve one additional patient with an independent functional outcome was in the range of 3-7, and benefit was additive to that of intravenous tissue plasminogen activator alone. Paroxysmal atrial fibrillation (AF) is a major cause of cryptogenic stroke with incidence expected to rise with the aging population. Since 2014, prolonged 30-day cardiac monitoring has been recommended as a part of transient ischemic attack and stroke workup in patients with cryptogenic stroke. Even longer term monitoring of 6 months to 1 year with external and implantable loop recorders improves rates of diagnosing AF. First available in 2010, the novel anticoagulants-dabigatran, apixaban, rivaroxaban, and edoxaban-have been compared with warfarin in the prevention of stroke in patients with nonvalvular AF. Apixaban demonstrated superiority in safety and efficacy, with the novel anticoagulants as a group having favorable risk-benefit profile at higher dosages compared with standard warfarin therapy.

CONCLUSIONS

Endovascular therapy is now standard of care for eligible patients with anterior large vessel occlusions. Prolonged cardiac monitoring is recommended for patients with cryptogenic stroke. The novel anticoagulants are an alternative to warfarin in patients with AF.

Eyes and stroke: the visual aspects of cerebrovascular disease

A large portion of the central nervous system is dedicated to vision and therefore strokes have a high likelihood of involving vision in some way. Vision loss can be the most disabling residual effect after a cerebral infarction. Transient vision problems can likewise be a harbinger of stroke and prompt evaluation after recognition of visual symptoms can prevent future vascular injury. In this review, we discuss the visual aspects of stroke. First, anatomy and the vascular supply of the visual system are considered. Then, the different stroke syndromes which involve vision are discussed. Finally, topics involving the assessment, prognosis, treatment and therapeutic intervention of vision-specific stroke topics are reviewed.

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.

Central Retinal Artery Occlusion: Acute Management and Treatment

PURPOSE OF REVIEW

This review will seek to answer if advances in ophthalmic imaging and evolution of treatment modalities have shed further light on the epidemiology, pathophysiology, diagnosis, and acute management of acute CRAO.

RECENT FINDINGS

Imaging characteristics of acute CRAO have been further characterized with the use of fluorescein angiography, optical coherence tomography (OCT), OCT-angiography, and indocyanine-green angiography. Layer segmentation of OCT imaging has found inner retinal layer hyper-reflectivity to be a common finding in acute CRAO. Non-invasive therapies, fibrinolytic delivery, and surgical interventions for acute CRAO have been further evaluated as potential management tools.

SUMMARY

A large body of literature reports very inconsistent treatment success with a wide variety of modalities. Currently, there is no clear evidence supporting the use of fibrinolytics in acute CRAO. Large, multicenter, randomized control trials are necessary to elucidate the role of the various acute treatment options in the management of CRAO.

Management of acute central retinal artery occlusion: Intravenous thrombolysis is feasible and safe

Background

Although acute central retinal artery occlusion is as a stroke in the carotid territory (retinal artery), its management remains controversial. The aim of this study was to assess the feasibility and safety of intravenous thrombolysis delivered within 6 h of central retinal artery occlusion in French stroke units.

Methods

We performed a retrospective analysis of patients treated with intravenous alteplase (recombinant tissue-plasminogen activator), based on stroke units thrombolysis registers from June 2005 to June 2015, and we selected those who had acute central retinal artery occlusion. The feasibility was assessed by the ratio of patients that had received intravenous alteplase within 6 h after central retinal artery occlusion onset among those who had been admitted to the same hospital for acute central retinal artery occlusion. All adverse events were documented.

Results

Thirty patients were included. Visual acuity before treatment was limited to “hand motion”, or worse, in 90% of the cases. The mean onset-to-needle time was 273 min. The individuals treated with intravenous alteplase for central retinal artery occlusion represented 10.2% of all of the patients hospitalized for central retinal artery occlusion in 2013 and 2014. We observed one occurrence of major bleeding, a symptomatic intracerebral hemorrhage.

Conclusion

When applied early on, intravenous thrombolysis appears to be feasible and safe, provided that contraindications are given due consideration. Whether intravenous thrombolysis is more effective than conservative therapy remains to be determined. In order to conduct a well-designed prospective randomized control trial, an organized network should be in place.

Hypothermia Protects and Prolongs the Tolerance Time of Retinal Ganglion Cells against Ischemia

Purpose

Hypothermia has been shown to be neuroprotective in the therapy of ischemic stroke in the brain. To date no studies exist on the level of the inner retina and it is unclear if hypothermia would prolong the ischemic tolerance time of retinal ganglion cells, which are decisive in many ischemic retinopathies.

Methods

Bovine eyes were enucleated and stored either at 21°C or 37°C for 100 or 340 minutes, respectively. Afterwards the globes were dissected, the retina was prepared and either the spontaneous ganglion cell responses were measured or the retina was incubated as an organotypic culture for additional 24 hours. After incubation the retina was either processed for histology (H&E and DAPI staining) or real-time PCR (Thy-1 expression) was performed.

Results

Hypothermia prolonged ganglion cell survival up to 340 minutes under ischemic conditions. In contrast to eyes kept at 37°C the eyes stored at 21°C still showed spontaneous ganglion cell spiking (56.8% versus 0%), a 5.8 fold higher Thy-1 mRNA expression (not significant, but a trend) and a preserved retinal structure after 340 minutes of ischemia.

Conclusion

Hypothermia protects retinal ganglion cells against ischemia and prolongs their ischemic tolerance time.

Atrial Fibrillation and Coronary Artery Disease as Risk Factors of Retinal Artery Occlusion: A Nationwide Population-Based Study

We use Taiwanese national health insurance research database (NHIRD) to investigate whether thrombolism (carotid artery disease (CAD) as a surrogate) or embolism (atrial fibrillation (AF) as a surrogate) plays roles in later retinal artery occlusion (RAO) development and examine their relative weights. The relative risks of RAO between AF and CAD patients and controls were compared by estimating the crude hazard ratio with logistic regression. Kaplan-Meier analysis was used to calculate the cumulative incidence rates of developing RAO, and a log-rank test was used to analyze the differences between the survival curves. Separate Cox proportional hazard regressions were done to compute the RAO-free rate after adjusting for possible confounding factors such as age and sex. The crude hazard ratios were 7.98 for the AF group and 5.27 for the CAD group, and the adjusted hazard ratios were 8.32 and 5.34 for the AF and CAD groups, respectively. The observation time with RAO-free was shorter for AF compared with CAD group (1490 versus 1819 days). AF and CAD were both risk factors for RAO with different hazard ratios. To tackle both AF and CAD is crucial for curbing RAO.

Predictors of prognosis and treatment outcome in central retinal artery occlusion: local intra-arterial fibrinolysis vs. conservative treatment

INTRODUCTION

The study analyses patients' risk factors to determine prognostic and predictive factors in patients with acute central retinal artery occlusion (CRAO) treated in the randomized European Assessment Group for Lysis in the Eye (EAGLE) Study with local intra-arterial fibrinolysis (LIF) or conservative standard treatment (CST). These data could improve patient selection for either method.

METHODS

Post hoc statistical analysis of effects of risk factors on overall best corrected visual acuity (BCVA [logarithm of the minimum angle of resolution (logMAR)]) at baseline and month 1 (prognostic effect) and on the difference between outcome of CST and LIF (predictive effect) was conducted.

RESULTS

Seventy two of 84 EAGLE datasets were included. Prognostic effect: Patients with coronary heart disease (CHD) presented worse BCVA at baseline (0.39 logMAR, p = 0.0097). Patients with time from occlusion to treatment <12 h showed a trend to better vision gain at month 1 (-0.23 logMAR, p = 0.086), similarly smoking (-0.24 logMAR, p = 0.077). Predictive effect: Age (<60 years favours LIF -0.54 logMAR; >70 years favours CST 0.28 logMAR; interaction p = 0.070) and CHD (favours CST 0.44 logMAR; interaction p = 0.073) might be predictors of therapeutic outcome. There were no strong effects in multivariate analysis.

CONCLUSION

CHD, time from occlusion to treatment and smoking influence BCVA at baseline and at month 1 (prognostic effect). Patients treated within 12 h are more likely to profit from treatment. In multivariate analysis, there is no clear trend to benefit from LIF even in patients with young age, no CHD and early treatment. Based on this preliminary report on a rather small sample size, we do not recommend LIF in CRAO patients.

Evidence for an enduring ischaemic penumbra following central retinal artery occlusion, with implications for fibrinolytic therapy

The rationale behind hyperacute fibrinolytic therapy for cerebral and retinal arterial occlusion is to rescue ischaemic cells from irreversible damage through timely restitution of tissue perfusion. In cerebral stroke, an anoxic tissue compartment (the "infarct core") is surrounded by a hypoxic compartment (the "ischaemic penumbra"). The latter comprises electrically-silent neurons that undergo delayed apoptotic cell death within 1-6 h unless salvaged by arterial recanalisation. Establishment of an equivalent hypoxic compartment within the inner retina following central retinal artery occlusion (CRAO) isn't widely acknowledged. During experimental CRAO, electroretinography reveals 3 oxygenation-based tissue compartments (anoxic, hypoxic and normoxic) that contribute 32%, 27% and 41% respectively to the pre-occlusion b-wave amplitude. Thus, once the anoxia survival time (≈2 h) expires, the contribution from the infarcted posterior retina is irreversibly extinguished, but electrical activity continues in the normoxic periphery. Inbetween these compartments, an annular hypoxic zone (the "penumbra obscura") endures in a structurally-intact but functionally-impaired state until retinal reperfusion allows rapid recovery from electrical silence. Clinically, residual circulation of sufficient volume flow rate generates the heterogeneous fundus picture of "partial" CRAO. Persistent retinal venous hypoxaemia signifies maximal extraction of oxygen by an enduring "polar penumbra" that permeates or largely replaces the infarct core. On retinal reperfusion some days later, the retinal venous oxygen saturation reverts to normal and vision improves. Thus, penumbral inner retina, marginally oxygenated by the choroid or by residual circulation, isn't at risk of delayed apoptotic infarction (unlike hypoxic cerebral cortex). Emergency fibrinolytic intervention is inappropriate, therefore, once the duration of CRAO exceeds 2 h.