Effect of carotid endarterectomy on the ocular circulation and on ocular symptoms unrelated to emboli

Retinal vessel diameters and microvascular abnormalities in patients with carotid stenosis before and 6 months after carotid endarterectomy: A prospective study

PURPOSE

To assess retinal findings in patients with severe carotid stenosis (CS) before and after carotid endarterectomy (CEA) compared to those in controls.

METHODS

This study is based on 70 patients (male 81%, mean age 69) scheduled for CEA in Helsinki University Hospital and 41 healthy nonmedicated controls (male 76%, mean age 68). Our examinations included fundus photographs. Semi-automated software (Vesselmap, Imedos) served for evaluation of central retinal arterial equivalent (CRAE) and venular equivalent (CRVE), and arterio-venous ratio (AVR) in both eyes. We assessed fundus photographs to subjectively grade microvascular abnormalities in the ipsilateral eyes including focal arteriolar narrowing and irregularities, arteriolar wall reflex, arterio-venous crossing signs and arteriolar and venular tortuosity in the macula.

RESULTS

CRAE was similar in the ipsi-and contralateral eyes of our patients, and similar to that of the controls both pre- and postoperatively. Preoperatively, we observed higher CRVE in the patients' ipsilateral than in their contralateral eyes (222 vs. 217 μm, p = 0.009), and likewise higher than in controls' eyes (222 vs. 214 μm, p = 0.024). CRVE decreased postoperatively in the patients' ipsilateral eyes (222 vs. 217 μm, p = 0.037). Among the microvascular abnormalities, arteriolar and venular tortuosity in the macula showed higher grades in the patients than in the controls preoperatively (p = 0.035 and p = 0.043), but not postoperatively (p = 0.15 and p = 0.10).

CONCLUSIONS

CRVE decreased after CEA, showing that venules constrict after the mechanical hindrance of blood flow is removed. Higher grades in arteriolar and venular tortuosity in the macula, a potential ocular biomarker of CS, subsided after CEA.

Flicker-induced retinal vascular dilation in ipsi- and contralateral eyes of patients with carotid stenosis before and after carotid endarterectomy: a prospective study

PURPOSE

Retinal vascular function was assessed in patients with carotid stenosis (CS) before and six months after carotid endarterectomy (CEA) and in controls at a six-month interval.

METHODS

We studied 68 patients (81% male, mean age 69) and 41 healthy non-medicated controls (77%, 68) from March 2015 to December 2018. Our ophthalmological examination included flicker-induced arteriolar and venular measurements with a Dynamic Vessel Analyser in both eyes.

RESULTS

At baseline, flicker-induced arteriolar and venular dilation was reduced in the ipsilateral eyes of the patients compared with dilation in the controls (arteriolar 1.0% versus 2.6%, p = 0.001 and venular 2.2% versus 2.8%, p = 0.049). These differences subsided after CEA. In patients' ipsilateral eyes, flicker-induced arteriolar dilation was borderline postoperatively (preoperative 1.0% versus postoperative 1.6%, p = 0.06), whereas venular dilation increased (2.2% versus 2.8%, p = 0.025). We found various tentative associations with the change in flicker-induced dilations after CEA, but not with the preoperative dilations.

CONCLUSIONS

Postoperative recovery of the reduced flicker-induced arteriolar and venular dilatation in the ipsilateral eye shows that, after CEA, the activity-dependent vascular reactivity of haemodynamically compromised retinal tissue can improve.

Ocular signs of carotid stenosis in ipsi- and contralateral eyes before and after carotid endarterectomy: a prospective study

PURPOSE

We describe hypoperfusion-related and embolic ocular signs of carotid stenosis (CS) before and six months after carotid endarterectomy (CEA) in a CS population.

METHODS

We enrolled prospectively 70 CEA patients (81% male, mean age 69) and 41 non-medicated control subjects (76%, 68), from March 2015 to December 2018, assessing intraocular pressure (IOP), best-corrected visual acuity (BCVA) in logMAR units and performing a bio-microscopy examination.

RESULTS

Main index symptoms included amaurosis fugax (Afx) (29, 41%) and hemispheric TIA (17, 24%), and 17 (24%) were asymptomatic. Of the 70, 17 patients (24%, 95% CI 16-36) showed ocular signs of CS. Of four embolic (Hollenhorst plaques) findings, one small macular plaque disappeared postoperatively. Four had hypoperfusion, that is ocular ischaemic syndrome (OIS), requiring panretinal photocoagulation: one for multiple mid-peripheral haemorrhages, two for iris neovascularization and one for neovascular glaucoma (NVG); only the NVG proved irreversible. Nine (de novo in three) showed mild OIS, that is only few mid-peripheral haemorrhages, ranging pre- /postoperatively in ipsilateral eyes from one to eleven (median two)/ one to two (median one), and in contralateral eyes from three to nine (median five)/ one to six (median three). Pre- and postoperative median BCVA was 0 or better, and mean IOP was normal, except in the NVG patient. Temporary visual impairment from 0 to 0.3 occurred in one eye soon after CEA due to ocular hyperperfusion causing macular oedema.

CONCLUSIONS

Ocular signs of CS are common in CEA patients, ranging from few mid-peripheral haemorrhages to irreversible NVG. Clinicians should be aware of these signs in detecting CS.

The effect of carotid revascularization on the ophthalmic artery flow: systematic review and meta-analysis

INTRODUCTION

High-grade internal carotid stenosis results in impaired flow dynamics in the ocular circulation that may lead to a rare clinical entity; ophthalmic ischemic syndrome (OIS). The aim of this study was to investigate hemodynamic changes in the ophthalmic circulation after carotid revascularization, assessed with duplex ultrasonography (DUS), and their potential impact on ocular function in patients suffering from OIS.

EVIDENCE ACQUISITION

A systematic review of the literature was performed according to the PRISMA guidelines. Medline, Embase and Central databases were searched.

EVIDENCE SYNTHESIS

The analysis included fourteen cohort studies (589 patients) reporting on the hemodynamic effect of carotid revascularization on the ophthalmic circulation using DUS. Eighty-five per cent of patients were treated for symptomatic carotid stenosis. The pre- and postoperative ophthalmological evaluation was recorded in four studies (227 out of 358 patients [63%] diagnosed with OIS). Reversed ophthalmic artery (OA) flow prior to carotid revascularization was present in 86 cases (24%). Following carotid revascularization, a significant increase in peak systolic velocity (PSV) (mean difference [MD] 14.712 cm/s, 95% confidence interval [CI] 10.566-18.858, P<0.001, I²=96%) and a significant anterograde restoration of flow in the OA (OR: 2.047, 95% CI: 1.72-2.42, P<0.001, Ι²=0%) were recorded. Carotid revascularization resulted in regression of ischemic symptoms in 93.1% of patients (95% CI: 56.4-99.3%), P=0.001, I²=82%).

CONCLUSIONS

Carotid revascularization may be associated with a significant flow restoration and PSV increase in the OA; as well as clinical improvement in ischemic ophthalmic symptoms in patients with OIS.

Carotid Endarterectomy for Ocular Ischemic Syndrome: A Case Report and Review of the Literature

Ocular ischemic syndrome is a rare complication of carotid arterial disease that can lead to irreversible vision loss. The disease is related to ocular hypoperfusion secondary to carotid stenosis. Carotid endarterectomy (CEA) has been proven to reduce the risk of embolic stroke in specific patient populations; however, the role of CEA in the treatment of ocular ischemic syndrome or other flow-related symptoms is less well defined. We present a case of ocular ischemic syndrome successfully treated with carotid endarterectomy, and summarize the current literature regarding management of ocular ischemic syndrome.

Retinal ganglion cell complex and peripapillary retinal nerve fiber layer thicknesses following carotid endarterectomy

PURPOSE

To examine changes in retinal ganglion cell complex (GCC) and peripapillary retinal nerve fiber layer (RNFL) thicknesses by optical coherence tomography (OCT) in contralateral and ipsilatateral eyes of carotid artery stenosis (CAS) patients before and after carotid endarterectomy (CEA).

METHODS

Forty-two consecutive patients diagnosed with CAS (70-99% stenosis rate) who underwent CEA were included in this prospective cross-sectional study. The indication for CEA was based on the Asymptomatic Carotid Atherosclerosis Study. Doppler ultrasonography and computed tomography angiography were performed to calculate CAS. All the subjects underwent an ophthalmological examination, including best corrected visual acuity (BCVA), intraocular pressure (IOP) measurements, biomicroscopy, fundoscopy, and OCT before and after the surgery.

RESULTS

The mean preoperative intraocular pressure was 15.2 ± 2.1 mmHg in the ipsilateral eye and 15.8 ± 2.7 in the contralateral eye. The mean postoperative intraocular pressure in the ipsilateral and contralateral eye was 18.6 ± 3.0 and 19.3 ± 3.8, respectively. The intraocular pressure was significantly higher in postoperative eyes (p = 0.0001). There was a statistically significant decrease in peripapillary RNFL thickness in superior quadrants postoperatively in ipsilateral eyes. The retinal GCC layer thickness was not significantly different before and after CEA in ipsilateral and contralateral eyes.

CONCLUSIONS

Carotid endarterectomy results in thinning of the superior peripapillary RNFL thickness. To the best of our knowledge, this is the first study to examine peripapillary RNFL and GCC thicknesses before and after CEA.

Electrophysiological function of the retina and optic nerve in patients with atrial fibrillation

Purpose

To evaluate the effects of atrial fibrillation (AF) and ablation procedures on electrophysiological function in the retina and optic nerve.

Methods

Thirty two eyes of 17 patients with AF were analyzed. The full-field electroretinogram (ERG), pattern electroretinogram (PERG) and pattern visual evoked potential (PVEP) were performed. The results were compared to age-matched healthy controls (n = 30). In 12 eyes, electrophysiological tests were performed before and 3 months after ablation treatment.

Results

Statistically significant differences between AF patients and healthy controls were detected. In the full-field ERG, a reduction in the oscillatory potentials wave index (OPs WI; p = 0.012) and scotopic (0 dB) a-wave amplitude (p = 0.009) was observed. The amplitude of b-waves, scotopic (24 dB; p = 0.011), photopic single flash (p = 0.008) and photopic flicker (p = 0.009), was decreased. The photopic flicker b-wave peak time was increased (p = 0.005). Other parameters of ERG/PERG/PVEP did not differ significantly from controls. After the ablation procedure, the only statistically significant change was an increase in the OPs WI (p = 0.002).

Conclusions

In the analyzed series of AF patients, retinal dysfunction was detected in the ERG test. The AF ablation may improve the retinal function as indicated by an increase in the OPs WI. The OPs WI has a potential value in the estimation of the effectiveness of AF ablation.

Deterioration of glaucoma after carotid endarterectomy

A 64-year-old man with a long history of untreated diabetes mellitus had suffered from visual disturbance in his right eye. Neovascular glaucoma in the right eye and diabetic retinopathy in both eyes were found, and ischemic ocular syndrome was suspected for the right eye. Neuroimaging revealed severe stenosis of the right internal carotid artery. He was first treated for diabetes and glaucoma, and then, after these conditions were stabilized, right carotid endarterectomy (CEA) was carried out. Although the operation was uneventful, he suffered from headache and his right sight was blurred on the day after surgery. Right intraocular pressure was markedly increased, and corneal edema and increased iris neovascularization were also recognized. Intensive ophthalmologic care was carried out, but his right vision worsened and was eventually lost. Ocular ischemia causes not only neovascularization of the iris, which leads to insufficient resorption of the aqueous humor, but also insufficient production of the aqueous humor. After CEA, production of the humor is immediately activated, but the resorption capacity does not change, which results in an extraordinary increase in intraocular pressure. Neurosurgeons should be aware that CEA not only improves or avoids worsening of vision in patients with ischemic oculopathy, but can also rarely cause paradoxical devastating visual deterioration.

Retinal Circulation After Carotid Artery Revascularization

Doubts still exist concerning the mechanisms involved in ocular ischemic syndrome (OIS) and its dependence on carotid disease. We report findings from 14 surgical patients undergoing carotid artery reconstruction for symptomatic cerebrovascular disease. All of them had fluorescein angiography (FA) of the eye ipsilateral to the carotid operation before surgery and 3 months after to provide information regarding retinal circulation time. Before the surgical procedure, the mean circulation time was 29.4 ± 9.4 seconds (CI 95%: 24.5-34.3). After 3 months, a significant (P < .001) decrease in the circulation time was observed: 18.9 ± 8.4 seconds (CI 95%: 14.5-23.4). The present series demonstrates that carotid revascularization surgery improved retinal flow in approximately 80% of the patients.

Endogenous endophthalmitis following ipsilateral carotid endarterectomy

We report a case involving a 75-year-old lady who presented to our department of ophthalmology complaining of a 1 day history of ocular pain and reduced vision in the right eye, associated with rigors and diarrhoea. This patient, who had undergone a right carotid endarterectomy (CEA) 4 days previously, was subsequently confirmed to have developed endogenous endophthalmitis. To our knowledge, endogenous endopthalmitis has not previously been described as a postoperative complication of CEA, and should be considered in patients presenting with ocular complaints after this type of surgery.

Perimetric and retrobulbar blood flow changes following carotid endarterectomy

BACKGROUND

Carotid stenosis can produce visual changes. This study examines perimetric and retrobulbar blood flow changes following carotid endarterectomy (CEA) in patients without visual symptoms.

METHODS

Sixteen patients (13 male, three female) with bilateral carotid stenosis were included. Patients with a history of ophthalmic disease, including glaucoma, were excluded. Peak systolic velocity (PSV) in the ophthalmic artery (OA), central retinal artery (CRA), and short posterior ciliary arteries (SPCAs) was measured preoperatively and 12 months following CEA with color Doppler imaging (CDI), using a 7.5 MHz probe, at both the side operated upon and its fellow side. Automated static perimetry (Octopus 500 perimeter, G1x program) was performed at the same intervals. Mean sensitivity (MS), mean defect (MD), loss variance (LV) and corrected loss variance (CLV) were recorded.

RESULTS

Preoperative PSV in the OA was significantly lower in the side operated on. Preoperative perimetric parameters were significantly compromised, compared with normative data, in both eyes. Postoperatively, PSV had significantly improved in all vessels examined in the carotid that was operated on, but only in the OA and SPCAs in the fellow side. MD had significantly improved postoperatively for both eyes, whereas improvement in the other perimetric parameters examined was not statistically significant.

CONCLUSIONS

Perimetric changes occur in carotid stenosis. CEA results in the improvement of retrobulbar blood flow and perimetric parameters. Further research will be required to determine whether perimetric parameters may be used as additional indicators for carotid endarterectomy.

In situ confirmation of retinal blood flow improvement after carotid endarterectomy in a patient with ocular ischemic syndrome

PURPOSE

To report a patient with ocular ischemic syndrome due to an internal carotid artery stenosis in whom we confirmed improved retinal blood flow noninvasively after carotid endarterectomy.

DESIGN

Observational case report.

METHODS

Retinal flowmetry.

RESULTS

In a 72-year-old hypertensive man with a transient ischemic attack including dysgraphia, carotid angiography revealed approximately 90% stenosis of the left internal carotid artery. Standard carotid endarterectomy was performed. Postoperatively, good patency of the left internal carotid artery was confirmed by magnetic resonance angiography. We measured tissue blood flow in the fundus of each eye using a Heidelberg retina flowmeter before and after endarterectomy. Preoperative measurements showed reduction of blood flow in the left fundus, while values 3 months after surgery indicated a significant improvement of blood flow (P <.05, one-factor analysis of variance [ANOVA]).

CONCLUSIONS

Retinal flowmetry can noninvasively detect differences in retinal blood flow between eyes in a patient with unilateral internal carotid artery stenosis and also assess the improvement of retinal blood flow after carotid endarterectomy.

Extracranial cerebrovascular revascularization for chronic ocular ischemia

We investigated the demographics, presentation, and outcome of patients undergoing cerebrovascular reconstruction for chronic ocular ischemia (COI) at a single institution through a review of 17 patients over a 9-year period. A total of 558 extracranial cerebrovascular reconstructions were performed during the period of study. Seventeen patients (3%) suffered symptoms of COI. There were 19 symptomatic eyes and 15 asymptomatic eyes. Two patients suffered bilateral symptoms. Eighteen (95%) symptomatic eyes experienced rapidly degenerating global visual acuity, and one suffered bright-light amaurosis. Concomitant ocular pathology was present in 10 (59%) patients, consisting of glaucoma (n = 4), cataracts (n = 4), diabetic retinopathy (n = 3), and macular degeneration (n = 1). Symptomatic eyes were found to have significantly worse ipsilateral internal carotid artery (p = 0.004), external carotid artery (p = 0.002), aortic arch branch disease (p = 0.04), and vertebral artery disease (p = 0.04). All 17 reconstructions treated ipsilateral disease. Twelve patients (70.6%) had significant bilateral disease at the time of operation. Three patients underwent staged contralateral reconstruction. Following revascularization, subjective visual improvement or stabilization occurred in 16 patients (94%). A single patient worsened after developing acute narrow angle glaucoma in the perioperative period. Worse cerebrovascular disease is present ipsilateral to symptomatic eyes. When revascularization is performed, arrest of progression or improvement of symptoms occurs in most patients.

Orbital color Doppler imaging of optic nerve tumors

OBJECTIVE

To report changes in retinal arterial and venous blood flow pattern in two patients with tumors involving the entire optic nerve.

METHODS

Retrospective review of one patient with clinical and neuroimaging characteristics typical of bilateral optic nerve gliomas and one patient with a probable meningioma of the left optic nerve sheath.

RESULTS

The optic nerve glioma patient had reduced peak systolic velocity of central retinal arteries bilaterally, while the patient with an optic nerve sheath meningioma had relatively low central retinal artery flow velocity and intermittent blood flow in the central retinal vein on the affected side.

CONCLUSIONS

Reduced retinal arterial flow velocities in the setting of optic nerve gliomas may correlate with the presence of optic nerve disease. Phasic blood flow in the central retinal vein with optic nerve sheath meningioma may be the reason that some patients with this tumor develop retinal choroidal venous anastomoses.

Effect of carotid endarterectomy on chronic ocular ischemic syndrome due to internal carotid artery stenosis

OBJECTIVE

We evaluated the effect of carotid endarterectomy on chronic ocular ischemic syndrome due to internal carotid artery stenosis by use of data obtained from ophthalmic artery color Doppler flow imaging.

METHODS

We examined 11 patients with ocular ischemic syndrome due to internal carotid artery stenosis (>70% stenosis) who were being treated by carotid endarterectomy. Ophthalmic artery color Doppler flow imaging indicated ophthalmic artery flow direction and peak systolic flow velocity and was performed before and at 1 week, 1 month, and 3 months after surgery.

RESULTS

We assessed the ophthalmic arteries of 11 patients via color Doppler flow imaging. Before undergoing carotid endarterectomy, five patients showed reversed ophthalmic artery flow. In the other six patients who experienced antegrade ophthalmic artery flow, the average peak systolic flow velocity was 0.09 +/- 0.05 m/s (mean +/- standard deviation). Preoperative reversed flow resolved in each patient 1 week after undergoing surgery. All patients showed antegrade ophthalmic artery flow. The average peak systolic flow velocity in the patients who had preoperative antegrade flow rose significantly, to 0.21 +/- 0.14 m/s (P < 0.05). There was no significant change as compared with findings at 1 week after surgery. During the follow-up period (mean, 32.4 mo), no patients complained of recurrent visual symptoms. At the end of the study period, visual acuity had improved in five patients and had not worsened in the other six patients.

CONCLUSION

Carotid endarterectomy was effective for improving or preventing the progress of chronic ocular ischemia caused by internal carotid artery stenosis.

Effects of bypass on ocular ischaemic syndrome caused by reversed flow in the ophthalmic artery

Superficial temporal to middle cerebral artery bypass was useful for ocular ischaemic syndrome caused by reversed flow in the ophthalmic artery as shown by ophthalmic-artery colour doppler flow imaging.

The effects of carotid endarterectomy on ocular haemodynamics

PURPOSE

To determine the profile of blood flow velocities and resistive indices in the ocular vessels of patients with atherosclerotic carotid disease and characterise the effect of endarterectomy on these parameters.

METHODS

Following a preliminary study on healthy volunteers, ophthalmic colour Doppler ultrasound examinations were performed on 27 male and 11 female patients with carotid disease. These measurements were compared with central retinal artery perfusion pressures and intraoperative internal carotid artery stump pressures.

RESULTS

Significant changes were seen on the endarterectomised side. The peak systolic velocity in the ophthalmic artery, and resistive indices in the ophthalmic artery, central retinal artery and nasal posterior ciliary artery, rose from pre-operative values. No correlation between colour Doppler ultrasound measurements and intraoperative internal carotid artery stump pressures was present. When compared with ophthalmodynamometry readings, a relationship was noted with maximum velocities in the central retinal vein.

CONCLUSION

Carotid endarterectomy alters the haemodynamics in selected vessels of the ocular circulation as measured by colour Doppler ultrasound, but more work is required to determine the clinical utility of this investigative modality.