Optical coherence tomography-based determination of ischaemia onset - the temporal dynamics of retinal thickness increase in acute central retinal artery occlusion

Multimodal Imaging Characteristics and Correlation to Outcomes in Patients With Central Retinal Artery Occlusion Presenting to a Large Academic Center

PURPOSE

To characterize a large modern cohort of patients with central retinal artery occlusion (CRAO) by describing presenting features and outcomes relating to manually segmented optical coherence tomography (OCT) features, angiographic reperfusion, and visual recovery.

DESIGN

Retrospective clinical cohort study.

METHODS

Patients with CRAO (ICD-10: H34.1) initially presenting to a tertiary referral center between January 2017 and December 2021 were included. Demographics, eye exam findings, fundus photographs, OCT, and fluorescein angiography were analyzed. Main outcome measures included total and inner retinal thickness on macular OCT, reperfusion, visual outcomes, and development of neovascularization.

RESULTS

A total of 145 eyes of 144 patients with mean age at of 69.4 ± 13.6 years were included. The mean time to presentation was 1.6 ± 4.2 days, with 19% examined within 4.5 hours and 26% within 6 hours of vision loss. 19% had cilioretinal artery (CLRA) sparing. Mean initial visual acuity (VA) was 1.68 ± 1.10 Logarithm of the Minimum Angle of Resolution (LogMAR) (CLRA sparing) compared to 2.53 ± 0.58 LogMAR (non-CLRA sparing), P < .001. 32% had elevated inflammatory makers. Out of 47 eyes with final fluorescein angiography, one-third showed some reperfusion. Final vision was 1.40 ± 1.16 LogMAR (CLRA sparing) compared to 2.46 ± 0.81 (non-CLRA sparing), P < .001. A third of patients improved in VA in both groups, 27% of patients gained more than 2 lines of vision in the CLRA-sparing group and 36% in the non-CLRA-sparing group. 17% improved to better than 20/200 in CLRA-sparing and 4% in non-CLRA sparing. Overall, 11% developed neovascularization all in non-CLRA sparing. In a multiple linear regression, VA at presentation was associated with regaining vision of 2 lines or more (OR = 2.603, P = .007). OCT showed progressive thinning over time, reaching lowest measurements at 6 months, and stabilizing thereafter.

CONCLUSIONS

In this modern cohort of acute CRAO patients, presentation to a tertiary facility within 12 hours of symptoms was seen in almost half of the patients. Final VA improved in almost a third of the patients, however, vision better than the legal blindness limit was rare (∼5%). Interestingly, a third of patients had some mild elevation of systemic inflammatory markers. Better VA at presentation was associated with visual gain, while baseline OCT values had poor correlation with final outcome.

Eye stroke protocol in in the emergency department

BACKGROUND

Visual outcomes of acute central and branch retinal artery occlusions (CRAO/BRAO) are poor and acute treatment options are limited by delayed diagnosis. In the hyper-acute setting, the ocular fundus may appear "normal", making recognition challenging, but is facilitated by retinal optical coherence tomography (OCT), which is seldom available in emergency departments (ED). We evaluated the use of non-mydriatic ocular fundus photographs (NMFP) combined with OCT to facilitate ultra-rapid remote diagnosis and stroke alert for patients with acute vision loss presenting to the ED.

METHODS

Prospective evaluation of all CRAO/BRAO between 06/06/2023-06/06/2024 who had NMFP-OCT in our general ED affiliated with a stroke center.

RESULTS

Over 1 year, 22 patients were diagnosed with CRAO, 4 with BRAO. Five patients presented within 4.5 hours of vision loss onset, 6 within 4.5 to ≤12 hours and 15 within >12 to 24 hours. On average, NMFP-OCT was performed within 141 minutes of presentation to the ED (range 27- 422 minutes). Diagnosis of acute RAO was made remotely with NMFP-OCT within 4.5 hours in 4 patients, 2 of whom received intravenous thrombolysis. Of the 9 patients with NMFP-OCT within 12 hours of symptom onset, 5 patients had subtle retinal whitening on color fundus photograph, but all had OCT inner retinal hyper-reflectivity/edema.

CONCLUSION

Implementation of NMFP-OCT in a general ED enables rapid remote diagnosis of CRAO/BRAO and facilitates initiation of an eye stroke protocol in acute patients. OCT complements color fundus photography and provides greater diagnostic accuracy in hyperacute cases with near-normal appearing ocular fundi.

Early REperfusion therapy with intravenous alteplase for recovery of VISION in acute central retinal artery occlusion (REVISION): Study protocol of a phase III trial

RATIONALE

Meta-analyses of case series of non-arteritic central retinal artery occlusion (CRAO) indicate beneficial effects of intravenous thrombolysis when initiated early after symptom onset. Randomized data are lacking to address this question.

AIMS

The REperfusion therapy with intravenous alteplase for recovery of VISION in acute central retinal artery occlusion (REVISION) investigates intravenous alteplase within 4.5 h of monocular vision loss due to acute CRAO.

METHODS

This study is the randomized (1:1), double-blind, placebo-controlled, multicenter adaptive phase III trial.

STUDY OUTCOMES

Primary outcome is functional recovery to normal or mildly impaired vision in the affected eye defined as best-corrected visual acuity of the Logarithm of the Minimum Angle of Resolution of 0.5 or less at 30 days (intention-to-treat analysis). Secondary efficacy outcomes include modified Rankin Score at 90 days and quality of life. Safety outcomes include symptomatic intracranial hemorrhage, major bleeding (International Society on Thrombosis and Haemostasis definition) and mortality. Exploratory analyses of optical coherence tomography/angiography, ultrasound and magnetic resonance imaging (MRI) biomarkers will be conducted.

SAMPLE SIZE

Using an adaptive design with interim analysis at 120 patients, up to 422 participants (211 per arm) would be needed for 80% power (one-sided alpha = 0.025) to detect a difference of 15%, assuming functional recovery rates of 10% in the placebo arm and 25% in the alteplase arm.

DISCUSSION

By enrolling patients within 4.5 h of CRAO onset, REVISION uses insights from meta-analyses of CRAO case series and randomized thrombolysis trials in acute ischemic stroke. Increased rates of early reperfusion and good neurological outcomes in stroke may translate to CRAO with its similar pathophysiology.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT04965038; EU Trial Number: 2023-507388-21-00.

Central retinal artery occlusion or retinal stroke: a neurosonologist's perspective

In central retinal artery occlusion (CRAO) or retinal stroke, which is usually a vision-threatening condition, timely diagnosis is imperative to improve the chances of retinal preservation and to establish adequate secondary prevention measures. Even though retinal strokes have been traditionally assigned to the field of ophthalmology, while considering reperfusion therapy as the only way to avoid permanent vision loss, we suggest prompt evaluation of CRAO causes (primarily related to cardiovascular risk factors) performed by a well-organized interdisciplinary team (ophthalmologist and neurologist) in a neurovascular center with stroke expertise. Therefore, the most suitable adjunct method for rapidly diagnosing non-arteritic CRAO could be target transorbital ultrasound, performed by an experienced neurologist/neurosonologist in the stroke unit. Consequently, after an ophthalmological assessment, a final decision on thrombolytic therapy could be made. We accept that further research is obviously needed to determine whether transorbital ultrasound could replace ophthalmological investigation in the case of a suspected acute retinal stroke. We assert that retinal stroke requires interdisciplinary treatment in cooperation with neurologists and ophthalmologists, with an additive value for each to achieve the best results for the patient.

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.

Evaluation of Increase in Retinal Thickness as Diagnostic Marker in Central Artery Occlusion

PURPOSE

To evaluate the increase in retinal thickness as a marker in predicting the onset of central retinal artery occlusions.

METHODS

Retrospective clinical study conducted at one Swiss hospital. Electronic records were filtered for patients with artery occlusions. Optical coherence tomography data, including time between the imaging and ischemic event, were reviewed. Increase in relative retinal thickness was measured, defined as an increase in retinal thickness compared to the unaffected partner eye. This was correlated with the time from symptom onset. A cutoff value of relative increase of < 24.5% was applied, as suggested in previous studies. The results were compared to the time gathered from the electronic records, and sensitivity, specificity, positive predictive value as well as negative predictive value were calculated for predicting an ischemia time of < 4.5 h.

RESULTS

Forty-two eyes from 41 patients with central artery occlusions were identified. Fourteen were female. Mean age was 66.4 ± 15.8 years. Initial corrected visual acuity was 2.41 ± 0.68 logMAR, and 2.13 ± 0.87 logMAR at the last follow-up (p > 0.05). Of eyes with a visual acuity of counting fingers (n = 38) or worse, 89.5% showed no improvement during follow-up, while eyes with logMAR 1 or better (n = 4) improved. Thirteen eyes (13 patients) presented within 4.5 h of the ischemic event. Four patients received i. v. thrombolysis, with visual recovery in one. In 12 eyes with an ischemia time of < 4.5 h, relative increase was below 24.5%. In the remaining 29 eyes with > 4.5 h, relative increase was below 24.5% in 4 eyes and above 24.5% in 25 eyes. This yielded a sensitivity of 92.3%, a specificity of 86.2%, with a positive predictive value of 75.0% and a negative predictive value of 96.2%.

CONCLUSION

Central retinal artery occlusion is associated with severe vision loss. There is no current established therapy. Parameters that objectify the presence of a therapeutic window for thrombolysis are gaining in importance as patient history is often imprecise. Relative retinal thickness increase proved a noninvasive imaging parameter demonstrating adequate performance in detecting patients within the therapeutic window of thrombolysis. Further investigation of this parameter in central retinal occlusion is warranted.

Diffusion-weighted magnetic resonance imaging in early central retinal artery occlusion

INTRODUCTION

Restricted retinal diffusion (RDR) has recently been recognized as a frequent finding on standard diffusion-weighted imaging (DWI) in central retinal artery occlusion (CRAO). However, data on early DWI signal evolution are missing.

PATIENTS AND METHODS

Consecutive CRAO patients with DWI performed within 24 h after onset of visual impairment were included in a bicentric, retrospective cross-sectional study. Two blinded neuroradiologists assessed randomized DWI scans for the presence of retinal ischemia. RDR detection rates, false positive ratings, and interrater agreement were evaluated for predefined time groups.

RESULTS

Sixty eight CRAO patients (68.4 ± 16.8 years; 25 female) with 72 DWI scans (76.4% 3 T, 23.6% 1.5 T) were included. Mean time-delay between onset of CRAO and DWI acquisition was 13.4 ± 7.0 h. Overall RDR detection rates ranged from 52.8% to 62.5% with false positive ratings in 4.2%-8.3% of cases. RDR detection rates were higher in DWI performed 12-24 h after onset, when compared with DWI acquired within the first 12 h (79.5%vs 39.3%, p < 0.001). The share of false positive ratings was highest for DWI performed within the first 6 h of symptom onset (up to 14.3%). Interrater reliability was "moderate" for DWI performed within the first 18 h (κ = 0.57-0.58), but improved for DWI acquired between 18 and 24 h (κ = 0.94).

CONCLUSION

DWI-based detection of retinal ischemia in early CRAO is likely to be time-dependent with superior diagnostic accuracy for DWI performed 12-24 h after onset of visual impairment.

Visual Recovery in 2 Cases of Central Retinal Artery Occlusion Treated With Prompt Intra-ophthalmic Artery Fibrinolysis

BACKGROUND

Central retinal artery occlusion (CRAO) rapidly produces inner retinal ischemia and irreversible vision loss. Although many therapeutic interventions have been proposed, no interventions have proven effective in restoring vision in large randomized controlled trials and final visual outcome in most patients is very poor.

METHODS

Retrospective case series.

RESULTS

We describe 2 cases of CRAO occurring after uncomplicated cataract surgery under topical anesthesia and rapidly diagnosed. Both had very severe vision loss at presentation with dramatic improvement after intra-ophthalmic artery fibrinolysis administered 2.75 and 5.5 hours after symptom onset.

CONCLUSIONS

Sudden monocular vision loss is an ophthalmologic emergency as CRAO must be ruled out and if diagnosed, rapid intervention should be performed. Devastating vision loss can be prevented if interventional neuroradiology is trained and available on a 24-hour basis for administration of local intra-arterial thrombolysis.

Thrombolysis in central retinal artery occlusion: a retrospective observational study

BACKGROUND

There is no evidence-based therapy for non-arteritic central retinal artery occlusion (NA-CRAO). Intravenous thrombolysis (IVT) with alteplase in a time window < 4.5 h may lead to a favorable outcome. Purpose of this study was to investigate the feasibility, efficacy and safety of IVT in patients classified as functionally blind.

METHODS

We conducted a retrospective observational study of NA-CRAO-patients. All patients underwent an ophthalmological and neurological examination including cerebral magnetic resonance imaging (MRI) for assessment of additional stroke lesions. Patients were treated either conservatively or with IVT within 4.5 h. Visual acuity (VA) was evaluated in logMAR and a categorical analysis was performed.

RESULTS

Thirty-seven patients were included in the study, 21 patients in the conservative treatment group (CTG) and 16 patients in the IVT group. The median logMAR visual acuity at admission and discharge was similar in both groups. The medium symptom to treatment time in the IVT group was 158.0 min. 3 patients (19%) of the IVT group showed a favorable outcome, all CTG patients remained at the level of functional blindness. No serious adverse events were observed after IVT. MRI showed additional acute stroke in over one-third of the patients (n = 14).

CONCLUSIONS

Early intravenous thrombolysis therapy according to the current stroke protocol n a time window up to 4.5 h after the onset of symptoms was feasible and might be a potential treatment option for NA-CRAO. Patients with NA-CRAO are at very high risk of ischemic stroke and MRI should be done in all patients for optimized treatment and secondary stroke prevention. A prospective randomized study is required.

Central retinal artery occlusion - detection score

Purpose

To investigate the sensitivity and specificity of central retinal artery occlusion (CRAO)-Detection Score in diagnosing CRAO via questionnaire and without fundoscopy.

Methods

This prospective study enrolled 176 emergency patients suffering from acute visual loss, of whom 38 were suffering from CRAO. Before conducting any examination, we administered our questionnaire containing six questions, followed by a thorough ophthalmologic examination to make the diagnosis. Statistical analysis involved a LASSO penalised multivariate logistic regression model.

Results

Our receiver operating characteristic (ROC) analysis based on a LASSO penalised multivariate logistic regression model showed an area under the curve (AUC) of 0.9 - three out of six questions were selected by LASSO. Interestingly, the unweighted ROC analysis of only two questions (Short CRAO-Detection Score) yielded similar results with an AUC of 0.88. The short CRAO-Detection Score of 2 yielded 14% (4/28) false positive patients.

Conclusion

This prospective study demonstrates that a high percentage of CRAO patients are detectable with a questionnaire. The CRAO-Detection Score might be used to triage patients suffering acute visual loss, which is important as intravenous fibrinolysis seem to be time-dependent to be effective.

[Cardiovascular risk factors, haemostasis and antithrombotic treatment in retinal vessel occlusion]

Venous and arterial retinal vascular occlusions are age-related disorders, generally associated with classical cardiovascular risk factors, rather than an isolated ocular disease. As affected patients often also have an increased general risk for other vascular diseases, such as ischemic stroke, an interdisciplinary clarification of cardiovascular risk factors and systemic comorbidities is essential for all patients. Extended hemostaseological investigations may be recommended in those patients who do not match the typical risk profile. Patients at a young age by the time of manifestation, without conventional risk factors as well as patients with an increased risk of developing antiphospholipid syndrome may require a selective clinical investigation including testing for thrombophilic risk factors. Recent studies have clearly demonstrated an association between coagulation and lipid metabolism disorders and the development of both retinal vein and artery occlusions in specific subgroups of patients. Therapeutic approaches to treat retinal vascular occlusions or reduce the long-term risk of recurrences with anticoagulant or antiplatelet drugs have not gained widespread acceptance. However, intravenous thrombolysis may be a valuable treatment option for central retinal artery occlusions within a short time to treatment therapeutic window. For defined disorders of the coagulation system, the administration of antithrombotic drugs to reduce the general vascular risk can be a reasonable approach. This article provides an overview of cardiovascular risk factors, the general vascular risk and the current state of knowledge on ophthalmologically relevant disorders of coagulation and lipid metabolism in patients with venous and arterial retinal vascular occlusions.

[Optical coherence tomography in the differential diagnostics of important neuro-ophthalmological disease patterns]

There are many disease patterns that are treated jointly by neurologists and ophthalmologists, for which optical coherence tomography (OCT) is of important differential diagnostic significance. In this context neurologists are mainly confronted by two patient collectives: patients with an acute ischemic event, who present with an acute but painless monocular visual deterioration (for central retinal artery occlusion) or with a monocular visual field defect (for arterial branch occlusion or anterior ischemic optic neuropathy). The second collective is patients without ophthalmological symptoms but with conspicuous optic nerve findings (papilledema or optic disc drusen). In this overview article both patient collectives are considered separately. In addition, the most important OCT findings for optic neuritis are presented. Before the disease patterns are described in detail, the normal OCT findings and the diagnostic possibilities of OCT are explained.

Inner Retinal Layer Hyperreflectivity Is an Early Biomarker for Acute Central Retinal Artery Occlusion

Purpose

To investigate inner retinal hyperreflectivity on optical coherence tomography (OCT) as a potential biomarker indicating acute central retinal artery occlusion (CRAO).

Methods

A total of 56 patients at two university hospitals with acute CRAO (symptom onset ≤48 h) were included in this retrospective study. The optical intensity of the inner retinal layers was determined in both eyes and the relationship between symptom onset and inner retinal layer optical intensity in OCT scans compared to the unaffected fellow eye was analyzed. Several differential diagnoses [central retinal vein occlusion, anterior ischemic optic neuropathy, diabetic macular edema, and subretinal fibrosis/disciform scar (Junius-Kuhnt)] served as controls to validate optical intensity-based diagnosis of CRAO.

Results

CRAO strongly correlated with an increased inner retinal layer hyperreflectivity in this cohort with acute CRAO with a time since symptom onset ranging from 1.1 to 48.0 h. Receiver operating characteristic (ROC) analysis showed an area under the curve of 0.99 to confirm CRAO with a true positive rate of 0.93 and a false positive rate of 0.02. No correlation between optical intensity and time since symptom onset was noticeable. None of the differential diagnoses did show an elevated optical intensity of the inner retinal layers as it was detectable in CRAO.

Conclusion

OCT-based determination of inner retinal layer hyperreflectivity is a very promising biomarker for a prompt diagnosis of CRAO in an emergency setting. This may be of major interest to speed up the administration of a possible thrombolytic treatment.

[Optical coherence tomography in the differential diagnostics of important neuro-ophthalmological disease patterns]

There are many disease patterns that are treated jointly by neurologists and ophthalmologists, for which optical coherence tomography (OCT) is of important differential diagnostic significance. In this context neurologists are mainly confronted by two patient collectives: patients with an acute ischemic event, who present with an acute but painless monocular visual deterioration (for central retinal artery occlusion) or with a monocular visual field defect (for arterial branch occlusion or anterior ischemic optic neuropathy). The second collective is patients without ophthalmological symptoms but with conspicuous optic nerve findings (papilledema or optic disc drusen). In this overview article both patient collectives are considered separately. In addition, the most important OCT findings for optic neuritis are presented. Before the disease patterns are described in detail, the normal OCT findings and the diagnostic possibilities of OCT are explained.

Early Onset of Neovascular Glaucoma After Intra-Arterial Thrombolysis for Central Retinal Artery Occlusion: A Possible Complication?

Purpose

To report on four cases of central retinal artery occlusion (CRAO) treated with intra-arterial thrombolysis with early onset neovascular glaucoma in the further disease course.

Patients and Methods

Retrospective analysis of the medical records of six consecutive patients treated with intra-arterial thrombolysis for CRAO of which four developed neovascular glaucoma.

Results

All six patients were diagnosed with acute CRAO and treated with intra-arterial thrombolysis 4.5–6 hours after symptom onset. The patients had no significant carotid artery stenosis and unremarkable ophthalmic history. No visual improvement could be achieved after treatment. Four to seven weeks after CRAO onset, four of these patients developed severe painful neovascular glaucoma.

Conclusion

Early onset of aggressive neovascular glaucoma following intra-arterial thrombolysis for CRAO might be a complication of CRAO itself, still possible association with intra-arterial thrombolysis in our patients should be discussed.

Detectability of Retinal Diffusion Restriction in Central Retinal Artery Occlusion is Linked to Inner Retinal Layer Thickness

PURPOSE

To investigate retinal microstructure differences in central retinal artery occlusion (CRAO) patients with and without visible retinal diffusion restriction (RDR) on diffusion-weighted magnetic resonance imaging (DWI).

METHODS

Consecutive CRAO patients with available optical coherence tomography (OCT) and DWI, both performed within 7 days after symptom onset, were included in a retrospective cohort study. The OCT scans were reviewed to assess retinal layer thickness, optical intensity and structural integrity. The OCT findings were compared between patients with and without visible RDR on DWI using Mann-Whitney U or Pearson's Χ² test.

RESULTS

A total of 56 patients (mean age 70.8 ± 12.8 years) were included. RDR was observed in 38 subjects (67.9%) with visually correlating low ADC map in 26 of 38 cases (68.4%). Superior and inferior parafoveal macular thickness measurements (SMT, IMT) of RDR negative patients were significantly lower when compared to RDR+ patients (370.5 ± 43.8 µm vs. 418.2 ± 76.0 µm, p = 0.016; 374.4 ± 42.9 µm vs. 428.8 ± 63.2 µm, p = 0.004) due to differences in inner retinal layer thickness (IRLT, 188.8 ± 34.4 µm vs. 234.7 ± 49.0 µm, p = 0.002). IRLT values of RDR negative patients were higher in 1.5T compared to 3T the DWI (205.0 ± 26.0 µm vs. 168.6 ± 32.8 µm, p = 0.026).

CONCLUSIONS

Detectability of RDR is likely contingent upon the degree of ischemic retinal swelling in CRAO. Technical adjustments to the DWI protocol, such as increased field strength, may improve visibility of RDR.

Diagnosing Central Retinal Artery Occlusion (CRAO) without Fundus Examination

In the field of ophthalmology, central retinal artery occlusion is still one of the unsolved pathologies, as there is no widely accepted evidence-based therapeutic concept. Meta-analysis suggests that intravenous fibrinolysis might help to improve the outcome if performed within the first 4.5 hours after symptom onset. However, this short window of opportunity is often missed due to delays during diagnostic testing (e.g. time elapsed before performance of an ophthalmological examination) or patient-processing (referring the patient to a specialized medical facility). This article presents a diagnostic tool in the form of a simple questionnaire, comprising a medical history and examinations, which could help to minimize the time required to initiate the appropriate treatment.

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.

[Acute diagnostics of central retinal artery occlusion and biomarkers of ischemia : Diagnostics with consequences?]

BACKGROUND

Acute central retinal artery occlusion (CRAO) represents an ophthalmological emergency with neurological implications, which must be immediately investigated and treated. Intravenous thrombolysis could improve the prognosis only within the first 4.5 h due to limited retinal tolerance to ischemia. Accordingly, ophthalmological acute diagnostics should be reduced to the minimum necessary followed by immediate referral to a clinic with neurovascular expertise. The typical anamnesis is well-suited for triaging and should be carried out ín a standardized way in order to determine the onset of symptoms as exactly as possible. In addition to pathognomic findings in fundoscopy, there are characteristic ischemia-related changes in optical coherence tomography (OCT), which document ischemia in the inner retina and under some circumstances can provide inferences for the onset of ischemia.

OBJECTIVE

This review article summarizes the acute ophthalmological diagnostic management of acute CRAO with a focus on the typical OCT and transorbital ultrasound (TOUS) findings and discusses their potential use as ischemic biomarkers.

CONCLUSION

Characteristic biomarkers make OCT an important diagnostic tool in the management of acute CRAO. Additional information can be obtained by TOUS. With an evidence-based treatment established in the future both tools could be used for indications for treatment and for estimating the prognosis.

[Update on intravenous lysis treatment : The REVISION trial]

BACKGROUND

To date, no evidence-based treatment for acute non-arteritic central retinal artery occlusion (CRAO) exists. Considering the limited ischemia tolerance of the retina and the results of multiple case series, increasing expectations are directed towards an early intravenous thrombolysis within 4.5 h after CRAO onset.

OBJECTIVE

The current literature regards timely retinal reperfusion as the only potentially beneficial therapeutic option to treat non-arteritic CRAO. Available data on the efficacy and safety of thrombolysis in CRAO are presented and discussed. On the basis of these data, the prospective, randomized, double-blind, placebo-controlled REVISION trial (early REperfusion therapy with intravenous alteplase for recovery of VISION in acute central retinal artery occlusion) will shortly be initiated in 25 centers across Germany in order to investigate early intravenous thrombolysis in acute CRAO. The main inclusion criteria of the REVISION trial are outlined, which may help ophthalmologists to identify study candidates and facilitate rapid referral to a study center.

CONCLUSION

The efficacy of intravenous thrombolysis in acute ischemic stroke is critically time dependent. This may also be assumed in acute CRAO; however, definite evidence still needs to be provided. Until then, the motto "time is retina" should be applied and intravenous thrombolysis should be offered to CRAO patients as part of randomized trials (such as REVISION). According to the current literature, other acute treatment approaches (such as paracentesis) are not indicated.

Determination of Ischemia Onset Based on Automatically Generated Spectralis SD-OCT Values in Acute Central Retinal Artery Occlusion

Acute central retinal artery occlusion (CRAO) induces a time-dependent increase in retinal thickness. By manually measuring the relative retinal thickness increase (RRTI) in comparison to the contralateral eye based on optical coherence tomography (OCT), ischemia onset within the past 4.5 hours could be determined with 100% sensitivity and 94.3% specificity. To enable examiner-independent and quicker diagnostics, we analyzed the RRTI using the automatic retinal thickness measurement. In this retrospective study, 28 eyes were evaluated with an acute CRAO (<46 hours). All patients received a Spectralis SD-OCT image of both eyes. The RRTI was calculated for the ETDRS sectors using the Segmentation Module for Single Retinal Layer Analysis. Receiver operating characteristic (ROC) analysis was performed to determine patients ≤4.5 hours by RRTI. In all sectors, time to OCT (TTO) and RRTI correlated positively. The optimal cutoff point to detect CRAOs ≤4.5 hours was between 18.7% nasally and 22.9% RRTI temporally. Sensitivity and specificity varied between the sectors with 90-95% sensitivity and 89-100% specificity. In conclusion, the automatic measurement of RRTI also allows the differentiation of CRAOs within a possible therapeutic time window ≤4.5 hours and CRAOs ≥4.5 hours with a high sensitivity and specificity. Additionally, it offers quicker, easier, and a user-independent assessment of ischemia onset, helping to set a base for establishing automatic indices generated by the OCT machines.