Amaurosis fugax in a Danish community: a prospective study

Risk Factors and Treatment Strategy for Retinal Vascular Occlusive Diseases

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

Transient Monocular Visual Loss: When Is It an Emergency?

BACKGROUND

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

CASE REPORT

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

Arterial Occlusions to the Eye: From Retinal Emboli to Ocular Ischemic Syndrome

: Abstract: A loss or lack of blood supply to the eye can result in acute loss of vision. The site of ischemia may be at the level of the retinal arterioles, the central retinal artery, or further back at the ophthalmic and internal carotid artery. Recognizing the symptoms and signs are important to help prevent permanent ischemic and irreversible blindness. The objective of this review article is to provide the general ophthalmologists with information on how to recognize the symptoms and to best manage these patients. The management is to investigate for the cause of the transient monocular visual loss and to apply secondary prevention to address atherosclerotic risk factors to prevent further ischemic events like a stroke.

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.

Transient monocular blindness and the risk of vascular complications according to subtype: a prospective cohort study

Patients with transient monocular blindness (TMB) can present with many different symptoms, and diagnosis is usually based on the history alone. In this study, we assessed the risk of vascular complications according to different characteristics of TMB. We prospectively studied 341 consecutive patients with TMB. All patients were interviewed by a single investigator with a standardized questionnaire; reported symptoms were classified into predefined categories. We performed Cox regression analyses with adjustment for baseline vascular risk factors. During a mean follow-up of 4.0 years, the primary outcome event of vascular death, stroke, myocardial infarction, or retinal infarction occurred in 60 patients (annual incidence 4.4 %, 95 % confidence interval (CI) 3.4-5.7). An ipsilateral ischemic stroke occurred in 14 patients; an ipsilateral retinal infarct in six. Characteristics of TMB independently associated with subsequent vascular events were: involvement of only the peripheral part of the visual field (hazard ratio (HR) 6.5, 95 % CI 3.0-14.1), constricting onset of loss of vision (HR 3.5, 95 % CI 1.0-12.1), downward onset of loss of vision (HR 1.9, 95 % CI 1.0-3.5), upward resolution of loss of vision (HR 2.0, 95 % CI 1.0-4.0), and the occurrence of more than three attacks (HR 1.7, 95 % CI 1.0-2.9). We could not identify characteristics of TMB that predicted a low risk of vascular complications. In conclusion, careful recording the features of the attack in patients with TMB can provide important information about the risk of future vascular events.

A fatal case of primary cardiac chondrosarcoma presenting with amaurosis fugax

A 64-year-old previously healthy woman consulted her general practitioner because of recurrent episodes of right-sided monocular transient visual loss (ie, amaurosis fugax). At first, these symptoms were followed over time, but as the attacks worsened, and were accompanied by dizziness and general discomfort, the patient was admitted to the department of neurology for further investigations. CT of the brain was normal; however, during admission, the patient developed rapid atrial fibrillation and was transferred to the department of cardiology. Transthoracic echocardiography revealed a massive tumour on the atrial side of the anterior mitral valve leaflet, partly obstructing the mitral valve inflow. The tumour was excised and a biological prosthetic mitral valve inserted. The tumour was histologically determined to be a highly malignant dedifferentiated chondrosarcoma. After 6 months, the tumour relapsed and expanded aggressively to completely obstruct the mitral valve inflow, ultimately leading to cardiac arrest and death.

Internal jugular venous abnormalities in transient monocular blindness

Background

The etiology of transient monocular blindness (TMB) in patients without carotid stenosis has been linked to ocular venous hypertension, for their increased retrobulbar vascular resistance, sustained retinal venule dilatation and higher frequency of jugular venous reflux (JVR). This study aimed to elucidate whether there are anatomical abnormalities at internal jugular vein (IJV) in TMB patients that would contribute to impaired cerebral venous drainage and consequent ocular venous hypertension.

Methods

Contrast-enhanced axial T1-weighted magnetic resonance imaging (MRI) was performed in 23 TMB patients who had no carotid stenosis and 23 age- and sex-matched controls. The veins were assessed at the upper IJV (at C1–3 level) and the middle IJV (at C3–5 level). Grading of IJV compression/stenosis was determined bilaterally as follows: 0 = normal round or ovoid appearance; 1 = mild flattening; 2 = moderate flattening; and 3 = severe flattening or not visualized.

Results

There was significantly more moderate or severe IJV compression/stenosis in the TMB patients at the left upper IJV level and the bilateral middle IJV level. Defining venous compression/stenosis scores ≥ 2 as a significant cerebral venous outflow impairment, TMB patients were found to have higher frequency of significant venous outflow impairment at the upper IJV level (56.5% vs. 8.7%, p = 0.0005) and the middle IJV level (69.6% vs. 21.7%, p=0.0011).

Conclusions

TMB Patients with the absence of carotid stenosis had higher frequency and greater severity of IJV compression/stenosis which could impair cerebral venous outflow. Our results provide evidence supporting that the cerebral venous outflow abnormality is one of the etiologies of TMB.

Patterns of non-embolic transient monocular visual field loss

The aim of this study was to systematically describe the semiology of non-embolic transient monocular visual field loss (neTMVL). We conducted a retrospective case note analysis of patients from Moorfields Eye Hospital (1995-2007). The variables analysed were age, age of onset, gender, past medical history or family history of migraine, eye affected, onset, duration and offset, perception (pattern, positive and negative symptoms), associated headache and autonomic symptoms, attack frequency, and treatment response to nifedipine. We identified 77 patients (28 male and 49 female). Mean age of onset was 37 years (range 14-77 years). The neTMVL was limited to the right eye in 36 % to the left in 47 % and occurred independently in either eye in 5 % of cases. A past medical history of migraine was present in 12 % and a family history in 8 %. Headache followed neTMVL in 14 % and was associated with autonomic features in 3 %. The neTMB was perceived as grey in 35 %, white in 21 %, black in 16 % and as phosphenes in 9 %. Most frequently neTMVL was patchy 20 %. Recovery of vision frequently resembled attack onset in reverse. In 3 patients without associated headache the loss of vision was permanent. Treatment with nifedipine was initiated in 13 patients with an attack frequency of more than one per week and reduced the attack frequency in all. In conclusion, this large series of patients with neTMVL permits classification into five types of reversible visual field loss (grey, white, black, phosphenes, patchy). Treatment response to nifidipine suggests some attacks to be caused by vasospasm.

Reflux of jugular and retrobulbar venous flow in transient monocular blindness

OBJECTIVE

Transient monocular blindness (TMB) attacks may occur during straining activities that impede cerebral venous return. Disturbance of cerebral and orbital venous circulation may be involved in TMB.

METHODS

Duplex ultrasonography and Doppler-flow measurement of jugular and retrobulbar veins were performed in 134 consecutive patients with TMB and 134 age- and sex-matched control subjects. All recruited patients received thorough examinations to screen for possible underlying causes.

RESULTS

Of the 134 patients with TMB, 48 patients had ipsilateral carotid arterial lesion and 7 patients had TMB attack(s) caused by cardiac embolism. Of the remaining 79 patients with undetermined cause, 46 had 3 or more TMB attacks (undetermined-frequent group) and 33 had fewer than 3 attacks. In comparison with the control subjects, the TMB patients had greater frequencies of jugular venous reflux (57 vs 30%; p < 0.0001; odds ratio [OR]: 3.079, 95% confidence intervals [CI]: 1.861-5.096) and flow reversal in the superior ophthalmic vein (RSOV; 37 vs 9%; p < 0.0001; OR: 6.052, CI: 3.040-12.048). The undetermined-frequent group had the greatest frequencies of jugular venous reflux (74%, 34 patients; OR: 6.66, CI: 3.13-14.17) and RSOV (59%, 27 patients; OR: 6.51, CI: 3.12-13.58). Of the 50 patients with RSOV, 47 (94%) had RSOV on the side of the TMB attacks.

INTERPRETATION

The increased incidences of jugular and orbital venous reflux in TMB patients suggest that disturbance of cerebral and orbital venous circulation is involved in the pathogenesis of TMB, especially among patients with frequent attacks of undetermined cause.

Transient monocular blindness

An attack of abrupt loss of vision in one eye that recovers completely after a short period is called "transient monocular blindness" (TMB) or amaurosis fugax. The most common cause of TMB is atherothromboembolism from the origin of the internal carotid artery (ICA), whereas atrial fibrillation is quite uncommon. TMB also can be caused by anterior optic nerve ischemia, that is usually caused by thrombosis in the posterior ciliary artery. Thrombosis in the central retinal vein may be another cause. Dissection of the ICA, vascular malformations, or fibromuscular dysplasia are other potential etiologies. Blurring of vision as compared with blackened vision or positive phenomena such as flashing is probably associated with a higher risk of future cardiovascular events, whereas involvement of the partial monocular field is associated with a relative benign prognosis. In patients with atherosclerosis, antiplatelet therapy is indicated and treatment of vascular risk factors should have high priority. Carotid endarterectomy should be performed only in case of an ICA stenosis of more than 70% in the presence of at least one other risk factor for stroke.

Prognosis after transient monocular blindness associated with carotid-artery stenosis

BACKGROUND

Transient monocular blindness associated with internal-carotid-artery stenosis is a risk factor for stroke. The effect of carotid endarterectomy in patients who present with transient monocular blindness has not been determined.

METHODS

We compared the risk of stroke among patients presenting with transient monocular blindness with the risk among patients presenting with hemispheric transient ischemic attack. The effect of endarterectomy was assessed in patients with transient monocular blindness. The analyses were based on data from the North American Symptomatic Carotid Endarterectomy Trial.

RESULTS

A total of 198 medically treated patients with transient monocular blindness had a three-year risk of ipsilateral stroke that was approximately half of that among 417 medically treated patients with hemispheric transient ischemic attack (adjusted hazard ratio, 0.53; 95 percent confidence interval, 0.30 to 0.94). Six factors were associated with a higher risk of stroke in patients with monocular blindness--an age of 75 years or more, male sex, a history of hemispheric transient ischemic attack or stroke, a history of intermittent claudication, stenosis of 80 to 94 percent of the luminal diameter, and the absence of collateral circulation. The three-year risk of stroke with medical treatment for patients with zero or one risk factor was 1.8 percent, with two risk factors 12.3 percent, and with three or more risk factors 24.2 percent (P=0.003). The three-year absolute reduction in the risk of stroke associated with endarterectomy was -2.2 percent (i.e., a 2.2 percent increase in risk) among patients with zero or one risk factor, 4.9 percent among those with two risk factors, and 14.3 percent among those with three or more risk factors (P=0.23 by a test for interaction).

CONCLUSIONS

Among patients with internal-carotidartery stenosis, the prognosis was better for those presenting with transient monocular blindness than for those presenting with hemispheric transient ischemic attack. Among patients with transient monocular blindness, carotid endarterectomy may be beneficial when other risk factors for stroke are also present.

Microemboli are not a prerequisite in retinal artery occlusive diseases

PURPOSE

Retinal artery occlusion (RAO) is caused by arterio-arterial or cardiovascular emboli in about 50% of all cases, but the role of non-embolic causes remains unclear.

SUBJECTS AND METHODS

We studied 27 patients with amaurosis fugax (AFX), branch retinal artery occlusion (BRAO), central retinal artery occlusion (CRAO) and anterior ischaemic optic neuropathy (AION). Patients underwent an evaluation of cerebrovascular and cardiovascular risk factors, measurement of haemorheological parameters, and Doppler/duplex sonography including ultrasound detection of cerebral microembolic signals and echocardiography.

RESULTS

Forty-one per cent of the patients had internal carotid atherosclerosis but only one patient had microembolic signals, probably due to a cardiac thrombus. Vascular risk factors, especially hypertension, were present in 82% of the patients correlating with abnormal haemorheological parameters such as increased thrombocyte reactivity.

CONCLUSIONS

Our results indicate that altered haemorheological parameters, especially increased thrombocyte reactivity and vascular risk factors such as arterial hypertension, are non-embolic causes of vascular disease in a significant number of patients with RAO. This should guide diagnostic and therapeutic considerations concerning RAO in cases without proven embolic sources.

Carotid duplex scanning: patterns of referral and outcome

OBJECTIVE

Review of the results of carotid Duplex scanning.

DESIGN

Retrospective review of new referrals for carotid Duplex scanning to a regional vascular laboratory.

MATERIALS

1041 referrals made over an 18 month period.

METHODS

Referrals were reviewed for scan quality, diagnostic category and outcome of scanning.

RESULTS

The overall detection rate of ipsilateral stenoses > 70% and occlusions was 13.5%; the detection rate of surgically significant carotid lesions (70-99%) was only 8%. Analysis by diagnostic category revealed a significantly greater detection rate for carotid lesions > 70% in patients presenting with amaurosis fugax (24%) in comparison to those with TIAs (9.5%, p = 0.0005) or following a stroke (13%, p = 0.01). Patients referred with asymptomatic bruits or prior to cardiac surgery showed a positive scan rate of 30%. Sixty-seven carotid endarterectomies have resulted from scans performed in this period.

CONCLUSION

The overall rate of detection for surgically relevant lesions is low, but in comparison to a similar audit conducted in 1992, the absolute number of carotid lesions > 70% has risen by 60%. An 8% detection rate for surgically relevant lesions may be valuable in projecting the need for carotid endarterectomy arising from a given number of Duplex scans.

Distribution of ischemic cerebrovascular events in cardiac embolism

Distribution and number of ischemic cerebrovascular events were studied in 57 patients who suffered from heart disorders with proven or highly probable source of cardiac embolism and compared to 39 patients with ulcerations of the craniocervical vessels. Patients with coexisting lesions were excluded from the present study. Out of the 57 patients with cardiac disorders, a single episode of cerebral embolism occurred in 33 patients. Of the 24 patients with recurrent ischemic episodes, different vascular territories were involved in only six cases. There was no evidence of a distinct distribution of vascular territories involved in cerebral embolism. The left middle cerebral artery was affected in 42.9%, the right middle cerebral artery in 23.8%, the vertebrobasilar territory in 19%, and the ophthalmic arteries in 14.2%. Statistical analysis revealed no significant differences in lesion localization between the group with a cardiac source of embolism and the group with ulcerations of the craniocervical vessels. There was a high frequency of patients with recurrent cardiogenic emboli in the ophthalmic (6 of 9 patients) as well as in the vertebrobasilar (6 of 12 patients) circulation who experienced a delayed initiation of cardiac assessment. The possibility of cardiac embolism should be considered in any patient with cerebral ischemia, independently of the vascular territory affected.