Clinical significance of the ophthalmic artery in carotid artery disease

Evolution of the Flow Patterns After Endovascular Treatment in Patients with High-Grade Carotid Artery Stenosis - the Clinical Value of Insonation of the Supratrochlear Artery and Alternating Flow

AIM

We aimed to describe the evolution of flow pattern in the ophthalmic artery (OA) and supratrochlear artery (SA) by transcranial Doppler (TCD) ipsilateral to a severe proximal carotid artery stenosis before and after staged endovascular treatment (EVT).

METHODS

We insonated and recorded the flow patterns of OA and SA in 63 patients with ≥ 80% carotid artery stenosis before and after staged carotid angioplasty and stenting at 2-4 weeks apart. Based on the direction of OA and SA blood flow, we categorized patients into (1) reversed, (2) alternating, or (3) forward flow, groups. We evaluated the evolving sonographic flow patterns in OA and SA at the 3-time points and correlated them with the stenotic and flow velocity change.

RESULTS

Despite the disconcordance between OA and SA, the evolution of flow direction were evoluted from reversed to alternating or from alternating to forward in both OA and SA. OA and SA's disagreement rate at three-time points was 19.1%, 49.2%, and 28.6%, respectively. After angioplasty alone, we detected an alternating flow in 21 (33.3%) and 46 (73.0%) patients in OA and SA, respectively. Alternating flow patterns in SA persisted in 20 patients (31.7%) after stenting. The post-angioplasty residual stenosis did not differ between the three flow pattern groups (p>0.05).

CONCLUSIONS

An alternating flow in OA or SA might mark the hemodynamic recovery after EVT. Insonation of SA may provide supporting evidence for hemodynamic change in patients with carotid artery stenosis undergoing EVT.

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.

Effects of Obstructive Carotid Artery Disease on Ocular Circulation and the Safety of Carotid Artery Stenting

BACKGROUND

The aims of this study were to examine the ophthalmic artery flow changes in patients with obstructive carotid artery disease, evaluate the orbital blood flow changes after carotid artery stenting and assess the safety of carotid stenting procedure by using transorbital colour and spectral Doppler sonography.

METHODS

Thirty-one consecutive patients scheduled for carotid stenting with severe internal carotid artery stenosis (>60%; the study group) and 30 control subjects were included. Ophthalmic artery (OA) Doppler sonography was performed in the control group and study group before and after stenting. Peak systolic velocity (PSV), end-diastolic velocity (EDV), pulsatility index (PI), and resistive index (RI) and systolic/diastolic ratio (S/D) in the ophthalmic artery were recorded. Statistical comparisons were made between controls and study group before stenting and before and after stenting in the study group.

RESULTS

Comparison between control and study group before stenting revealed a statistically significant decrease in OA PSV (51.5±14.5 vs. 39.7±19cm/sec, p= 0.008) and EDV (15.2±4.5 vs. 11.3±5.7cm/sec, p=0.004) in the study group. Differences in PI (1.3±0.14 vs. 1.36±0.4, p=0.47), RI (0.7±0.04 vs. 0.75±0.21, p=0.19), and S/D (3.5±0.6 vs. 3.6±1, p= 0.5) ratio were not statistically significant between groups. Peak systolic velocity (39.7±18.9 vs. 51.3±22.2cm/sec, p <0.001), RI (0.75±0.21 vs. 0.81±0.13, p=0.16) and S/D ratio (3.6±1 vs. 4.6±1.5, p= 0.001) were found to be significantly increased in the study group after stenting compared to baseline. There were no statistically significant differences in EDV and RI EDV(11.3±5.7 vs. 11.7±5.7cm/sec, p=0.66), PI (1.36±0.4 vs. 1.6±0.6, p =0.047) after stenting.

CONCLUSIONS

Ophthalmic artery flow parameters were significantly lower in patients with severe carotid artery stenosis compared to control, indicating compromised ocular blood flow in severe carotid stenosis. Flow indicators significantly improved after stent implantation suggesting the importance of revascularisation in restoring ocular blood flow and safety of carotid stenting.

Anterior segment neovascularization in diabetic retinopathy: a masquerade

Purpose

Anterior segment neovascularization (ASNV) could be a masquerade for ocular ischemic syndrome (OIS) in diabetic patients which misleads diagnosis and treatment. The purpose of our study is to find the relationship between blood flow velocity in carotid siphon and the development of ASNV in diabetic.

Methods

We reviewed 34 eyes of 17 diabetic patients who had Transcranial Color Doppler (TCD) examination with unilateral ASNV. The circulatory parameters of both eyes of each patient were compared and analyzed. In addition, 9 patients with more than 50% stenosis of extracranial internal carotid artery (ICA) and low velocity flow through TCD had been treated by carotid revascularization surgery.

Results

The maximal velocity in systole (Vmax) of carotid siphon (SCA) was lower in the eyes with ASNV than in the eyes without ASNV (P<0.05). ASNV of all the 9 patients regressed totally and BCVA improved significantly (P<0.05). Stenosis of ICA and arm-retina time (ART) decreased significantly (P<0.01) and SCA and ophthalmic artery (OA) increased significantly (P<0.01).

Conclusions

Our study showed ASNV could be a masquerade for OIS in patients with diabetic retinopathy. The decreased blood flow velocity in carotid siphon is related to the development of ASNV. Circulatory parameters screening of SCA by TCD is important to help us to evaluate the blood flow in SCA, the possibility of development of ASNV, and the prognosis of the patient. Interference such as carotid endarterectomy (CEA) or carotid artery stenting (CAS) can be performed if necessary to improve the blood flow in SCA and make ASNV regression.

Effect of carotid artery stenting on ophthalmic artery flow patterns

OBJECTIVES

The purpose of this study was to assess the effect of carotid artery stenting on ophthalmic artery blood flow using transorbital color and spectral Doppler sonography and review the changes in relation to cerebral hemodynamics.

METHODS

Twenty-eight consecutive patients with severe internal carotid artery stenosis (≥ 70%) who were scheduled for carotid stenting were included. Ophthalmic artery Doppler sonography was performed bilaterally before and after stenting. The flow direction, peak systolic velocity (PSV), end-diastolic velocity (EDV), pulsatility index (PI), and resistive index in the ophthalmic artery were recorded.

RESULTS

Twenty male and 8 female patients with 10 right-sided and 18 left-sided stenoses were studied. The mean overall carotid stenosis ratio ± SD was 87.3% ± 9.9%. After stenting in the ophthalmic artery ipsilateral to the stenosis, significant increases in the PSV (-3.87 ± 48.81 to 46.70 ± 25.33 cm/s; P < .001), and EDV (-3.02 ± 16.31 to 11.24 ± 7.37 cm/s; P < .001) were detected, and the increase in the PI approached significance (1.40 ± 0.59 to 1.62 ± 0.52; P = .055). A change in the flow direction from retrograde to antegrade was noted in 11 patients (39%) after stenting, and in 1 patient with no detectable flow, reconstitution of flow was observed. Increases in the PSV and EDV (P= .03 for ΔEDV) were more pronounced in symptomatic patients than asymptomatic patients after stenting.

CONCLUSIONS

Substantially decreased ophthalmic artery velocity and retrograde flow are suggestive of high-grade carotid artery stenosis (≳90%). Stenting improves ophthalmic artery perfusion and positively changes cerebral hemodynamics in high-grade carotid artery stenosis, especially in symptomatic patients, which can be monitored with ophthalmic artery Doppler sonography.

Carotid artery stenting improves cerebral hemodynamics regardless of the flow direction of ophthalmic artery

We enrolled 221 patients with elective carotid artery stenting (CAS). Patients with contralateral carotid stenosis exceeding 50%, insufficient vertebral artery (VA) flows, or angioplasty at subclavian artery were excluded. All patients underwent serial cerebral ultrasound studies. Of the 116 included patients, the direction of ophthalmic artery (OA) flow was forward in 74 patients while reversed in 42. The reversed flow group had worse ipsilateral stenosis, higher hemoglobin, and cardiac output. After CAS, the reversed flow group had an immediate recovery of ipsilateral internal carotid artery flow volume (FV; P < .0001), time average velocity (TAV) of middle cerebral artery (P = .02), and normalization of OA flow. The forward flow group had gradual decrement in TAV of contralateral anterior cerebral artery (P = .01) and total FV of VA (P = .001). Our results suggest CAS improves cerebral hemodynamics through different ways regardless of the direction of OA flow.

Reversal of ophthalmic artery flow and stroke outcomes in Asian patients with acute ischemic stroke and unilateral severe cervical carotid stenosis

Background

The aim of this study was to assess the clinical implications of reversed ophthalmic artery flow (ROAF) for stroke risk and outcomes in subjects with unilateral severe cervical carotid stenosis/occlusion.

Methods

We investigated 128 subjects (101 with acute stroke and 27 without), selected from a large hospital patients base (n  =  14,701), identified with unilateral high-grade cervical carotid stenosis/occlusion by using duplex ultrasonography and brain magnetic resonance imaging. All clinical characteristics were compared for stroke risk between acute stroke and nonstroke groups. Patients with acute stroke were divided into 4 subgroups according to ophthalmic artery flow direction and intracranial stenosis severity, and stroke outcomes were evaluated.

Results

The acute stroke group had significantly higher percentages of ROAF (52.5%, p  =  0.003), carotid occlusion (33.7%, p  =  0.046), and severe intracranial stenosis (74.3%, p<0.001). However, multivariate analysis demonstrated that intracranial stenosis was the only significant risk factor (odds ratio  =  10.38; 95% confidence interval  =  3.64–29.65; p<0.001). Analysis of functional outcomes among the 4 subgroups of patients with stroke showed significant trends (p  =  0.018 to 0.001) for better stroke outcomes from ROAF and mild or no intracranial stenosis. ROAF improved 10–20% stroke outcomes, as compared to forward ophthalmic artery flow, among the patients with stroke and the same degree of severities of intracranial stenosis.

Conclusions

Patients with acute stroke and severe unilateral cervical carotid stenosis/occlusion significantly have high incidence of intracranial stenosis and ROAF. Intracranial stenosis is a major stroke risk indicator as well as a predictor for worse stroke outcomes, and ROAF may provide partial compensation for improving stroke outcomes.

Ocular Circulation and Chronic Ocular Ischemic Syndrome before and after Carotid Artery Revascularization Surgery

Background. We evaluated the effect of carotid revascularization surgery on ocular circulation and chronic ocular ischemic syndrome (OIS). Methods. We examined ninety patients with carotid artery stenosis (more than 50% stenosis) at its origin treated with carotid endarterectomy (N = 56) or carotid artery stenting (N = 34). Twenty-five patients (28%) complained of chronic OIS. Ocular circulation was examined before and after revascularization surgery using ophthalmic artery (OphAr) and central retinal artery (CRA) color Doppler flow imaging. Results. (1) Ocular circulation: preoperatively, the average OphAr peak systolic flow velocity (Vs) was 0.05 m/sec, and the average CRA Vs was 0.07 m/sec. At 1 week after surgery, the average OphAr Vs significantly increased to 0.32 (P < 0.05), and the average CRA Vs significantly increased to 0.11 m/sec (P < 0.05). These significant improvements were sustained throughout the three months of the followup. (2) OIS: during the follow-up period (mean: 3.6 years), 15 patients (60%) showed visual acuity improvement, and no patients complained of amaurosis fugax or worsening of the chronic OIS. Conclusion. Carotid revascularization surgery was effective in improving the ocular circulation, and it was also useful for the chronic OIS due to the carotid artery stenosis.

Reversal of ophthalmic artery flow as a predictor of intracranial hemodynamic compromise: implication for prognosis of severe carotid stenosis

BACKGROUND AND PURPOSE

High-grade cervical carotid stenosis (70-99%) or occlusion often accompanies reversed ophthalmic artery flow (ROAF), but its potential clinical significances remain poor understood. This study assessed ROAF and the related variables caused by carotid hemodynamic compromise in patients with unilateral severe cervical carotid stenosis.

METHODS

The study consisted of 200 patients diagnosed as unilateral high-grade cervical carotid stenosis/occlusion using ultrasonography. The hemodynamic parameters of 152 patients, excluding 48 with cervical carotid occlusion, were compared based on the presence of ROAF. Out of 200 patients, 159 underwent brain magnetic resonance imaging and were analysed for risk factors impacting functional outcomes including ROAF.

RESULTS

The patients (n = 48) with internal carotid artery occlusion had significantly higher incidence (62.5%) of ROAF compared with that of 25.0% in those patients (n = 152) with unilateral high-grade carotid stenosis (P < 0.001). In ROAF patients (n = 38) with the unilateral high-grade stenosis, a significant retrobulbar arteries hemodynamic difference was observed between the stenotic and non-stenotic vessels. The patients (n = 159) with history of stroke (P = 0.035), ROAF (P = 0.023) and intracranial stenosis (P < 0.001) exhibited significantly higher incidence of poor functional outcome compared with the corresponding control groups. In the same patients (n = 159), those with both cervical and intracranial stenosis showed sevenfold higher risk (OR, 7.60; 95% CI, 3.44-16.81) for ROAF than those with only cervical stenosis.

CONCLUSIONS

ROAF may result from intracranial hemodynamic compromise. Patients with unilateral high-grade cervical carotid stenosis/occlusion in combination with intracranial stenosis appear to be a significant risk factor for poor functional outcome and increased incidence of ROAF.

Effect of carotid artery stenting on ocular circulation and chronic ocular ischemic syndrome

BACKGROUND

The authors evaluated the effect of carotid artery stenting (CAS) on ocular circulation and chronic ocular ischemic syndrome.

METHODS

We examined 38 patients with carotid artery stenosis (>80%) at its origin treated with CAS. Ocular circulation and symptoms were examined before, within 24 h, and 1 week, 1 month, and 3 months after CAS based on ophthalmic artery color Doppler flow imaging and ophthalmological examinations.

RESULTS

Ocular circulation: Before CAS, 13 patients showed reversed ophthalmic artery flow, and 25 antegrade flow. Average peak systolic flow velocity was -0.038 m/s. Within 24 h after CAS, all patients showed antegrade ophthalmic artery flow; reversed flow before CAS was thus resolved. Average peak systolic flow velocity rose significantly to 0.36 m/s (p < 0.05). One week, 1 month and 3 months after CAS, there were no significant changes compared to the findings at 1 week after CAS. Ocular symptoms: Before CAS, 8 patients showed chronic ocular ischemic syndrome. During the follow-up period (mean: 2.8 years), the visual acuity improved in 7 cases. Average retinal artery pressure and arm-to-retina circulation time improved significantly to the normal level (p < 0.05). The other 30 patients complained of recurrent and worsened visual symptoms during the follow-up period.

CONCLUSION

CAS was effective in improving ocular circulation, and also improved the chronic ocular ischemic syndrome caused by the severe carotid artery stenosis.

Effects of hormone replacement therapy on plasma viscosity and Doppler variations in postmenopausal non-smokers and heavy smokers

OBJECTIVES

To evaluate the effects of transdermal hormone replacement therapy (HRT) on some biological cardiovascular risk factors, specifically thromboxane B2 level and plasma viscosity. Furthermore, we investigated Doppler flow modifications at the level of the uterine, internal carotid, ophthalmic and bladder wall arteries, and evaluated whether there were significant differences, in the examined parameters, between postmenopausal women who were non-smokers and heavy smokers.

METHODS

Forty-three postmenopausal women (age 53.6 +/- 3.3 years, mean +/- standard deviation) participated in the study and were divided into two groups (Group I: n = 21, normal controls; and Group II: n = 22, heavy smokers). Patients were treated with continuous estradiol transdermal supplementation and 12-day courses of medroxyprogesterone acetate every 2 months. They were studied at baseline and after 6 months (in the estrogen-only phase of the cycle).

RESULTS

Results showed a beneficial effect of hormone substitution after 6 months of therapy. Plasma viscosity decreased significantly after 6 months of therapy both in non-smokers and heavy smokers (-18% and -14%, respectively). Plasma levels of thromboxane B2, which were similar at baseline, underwent a dramatic reduction in both Group I and Group II (-93% and -88%, respectively). Doppler assessment of pulsatility index at the level of the uterine, internal carotid, ophthalmic and bladder wall arteries showed a significant reduction in vascular impedance at the end of treatment in both groups. However, the treatment was significantly less beneficial, in terms of the analyzed factors, in heavy smokers.

CONCLUSIONS

Cigarette smoking represents a cardiovascular risk factor that can only partially be modified by the administration of transdermal HRT.

Time since menopause does not affect plasma viscosity, plasma thromboxane levels and Doppler findings

OBJECTIVES

To evaluate whether the use of transdermal hormone replacement therapy (HRT), in women within 5 years of menopause compared with women who were postmenopausal for > 5 years, would significantly influence thromboxane B2 levels, plasma viscosity and Doppler flow parameters at the level of the uterine, internal carotid, ophthalmic and bladder wall arteries.

METHODS

Thirty-five normal-weight (body mass index > 19 and < 25 kg/m(2)) postmenopausal women (age 54.6 +/- 3.9 years, mean +/- standard deviation) participated in the study and were divided into two groups (Group I: n = 19, time since menopause < 5 years; and Group II: n = 16, time since menopause > 5 years). Patients were treated with a continuous estradiol transdermal supplementation and 12-day courses of medroxyprogesterone acetate every 2 months. They were studied at baseline and after 6 months (in the estrogen-only phase of the cycle).

RESULTS

Results showed a beneficial effect of hormone substitution after 6 months of therapy. Baseline plasma viscosity was similar in both groups, and decreased significantly after therapy in both Group I (-17.5%) and Group II (-15.6%). Plasma levels of thromboxane B(2) were similar at baseline and diminished equally in Group I and Group II (-85.6% and -85.2%, respectively) after treatment. Doppler assessment of the pulsatility index at the level of uterine, internal carotid, ophthalmic and bladder wall arteries showed no differences between groups at baseline and revealed a significant reduction of vascular impedance at the end of the treatment in both groups.

CONCLUSIONS

Time since menopause does not affect the potential hemodynamic benefits of HRT in normal-weight women.

Transdermal hormone replacement therapy and Doppler findings in normal and overweight postmenopausal patients

The aim of this study was to evaluate the effects of transdermal hormone replacement therapy on some biological cardiovascular risk factors, specifically the thromboxane B2 levels, plasma viscosity and the lipid profile. Furthermore, we investigated the Doppler flow modifications at the level of the uterine artery, the internal carotid, the ophthalmic and the bladder wall arteries, and we finally evaluated whether there were significant differences in the examined parameters between normal and overweight postmenopausal women. Forty-five postmenopausal women (mean age+/-standard deviation, 53.5+/-3.8 years) participated in the study and were divided into two groups (27 with a body mass index of < 25 kg/m2 and 18 with a body mass index of > 25 kg/m2). Patients were treated with a continous estradiol transdermal supplement and a 12-day course of medroxyprogesterone acetate every 2 months, and were studied at baseline and after 6 months (in the estrogen-only phase of the second cycle). Our results showed a beneficial effect of hormone substitution on plasma viscosity, thromboxane B2 levels and lipid profile after 6 months of therapy and significant improvements of Doppler flow parameters in the examined vessels. Furthermore, we observed a lower impact of the treatment in overweight women. In conclusion, obesity represents an additional cardiovascular risk condition and it can only partially be modified by the administration of hormone replacement therapy.

Tibolone, oral or transdermal hormone replacement and colour Doppler analysis

OBJECTIVE

To compare the plasma thromboxane, the plasma viscosity and the Doppler flow modifications induced by tibolone and by oral or transdermal continuous combined hormone replacement therapy.

METHODS

Forty-two post-menopausal patients underwent either on: oral daily treatment with tibolone (2.5 mg) (Group I; n= 14); or continuous oral administration of 0.625 mg conjugated equine estrogens + medroxyprogesterone 5 mg per day (Group II; n = 14 ); or continuous estradiol transdermal supplementation, at a dose of 50 microg per day, + medroxyprogesterone 5 mg per day (Group III; n = 14 ). The duration of the study was 6 months and the patients were submitted to transvaginal ultrasonographic evaluation of pelvic organs; Doppler analysis of the uterine, internal carotid and ophthalmic arteries; thromboxane and plasma viscosity assays in basal condition, and at 1, 3 and 6 months from the beginning of the study.

RESULTS

Although the endometrial thickness increased significantly, there were no cases in which it exceeded the normal range (< or = 5 mm). In all the three groups, the pulsatility index of the uterine, internal carotid and ophthalmic arteries significantly decreased during the therapy showing a reduced impedance since the first month of treatment. Similar variations were observed for the peak systolic blood flow velocity of the internal carotid and ophthalmic arteries. Hormone replacement therapy and tibolone induced a deep, significant and rapid decrease in plasma thromboxane and plasma viscosity levels.

CONCLUSIONS

Hormone replacement therapy and tibolone seem to have beneficial effects on vascular and hemorrheological parameters.

Ophthalmic artery flow direction on color flow duplex imaging is highly specific for severe carotid stenosis

BACKGROUND/PURPOSE

Collateral flow patterns are important risk factors for brain ischemia in the presence of internal carotid artery (ICA) stenosis or occlusion. Ophthalmic artery (OA) flow reversal, routinely studied by transcranial Doppler sonography, is an important marker for high-grade ICA stenosis or occlusion. The authors sought to define the value of assessing OA flow direction with color flow duplex ultrasonography (CDUS) in the setting of significant ICA disease.

METHODS

Of all patients having routine carotid ultrasound in the neurosonology laboratory between July 1995 and November 2000, 152 had both carotid and orbital (OA flow direction by reduced power orbital CDUS) examinations as well as angiographic confirmation of stenosis to which North American Symptomatic Carotid Endarterectomy Trial criteria could be applied. Degree of angiographic stenosis in these 152 patients (304 arteries) was correlated with OA flow direction.

RESULTS

Of 304 arteries, 101 had greater than 80% stenosis by angiogram. In 56 of these 101 arteries with high-grade stenosis or occlusion, the ipsilateral OA was reversed; however, OA flow direction was never reversed ipsilateral to arteries with less than 80% stenosis (sensitivity 55%, specificity 100%, negative predictive value 82%, and positive predictive value 100% for OA flow reversal as a marker of high-grade carotid lesions).

DISCUSSION/CONCLUSIONS

OA flow direction is easily studied with CDUS. Reversed OA flow direction is highly specific (100%) for severe ipsilateral ICA stenosis or occlusion, with excellent positive predictive value, moderate negative predictive value, and limited sensitivity. OA flow reversal is not only quite specific for severe ICA disease, which may be helpful if the carotid CDUS is difficult or inadequate, but may also provide additional hemodynamic insights (i.e., the inadequacy of other collateral channels such as the anterior communicating artery). OA evaluation can provide important hemodynamic information and should be included as part of carotid CDUS if there is any evidence of ICA stenosis or occlusion.

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.

Quantitative volumetry in patients with carotid disease--effects of acetazolamide

The intracranial effects of acetazolamide on flow velocities can be monitored noninvasively by transcranial Doppler (TCD) sonography. Extracranial volume flow changes can now reliably be measured with color duplex M-mode systems. The authors tested the volumetric effects of acetazolamide in patients with high-grade unilateral carotid disease to quantify the amount of flow changes. Patients in group 1 had a high-grade > 70% internal carotid artery (ICA) stenosis, without collateral flow through the ophthalmic artery (OA). Patients with occluded ICA were included in group 2 (patent OA collateralization) or group 3 (no OA collateralization) (n = 6 per group). In group 1, common carotid artery (CCA) volume flow in the stenotic (normal contralateral) side increased from 271 (388) ml/min by 52 (54%) with 1 g aceta-zolamide intravenously. Simultaneously, middle cerebral artery (MCA) flow velocities increased from 54 (56) cm/s by 47 (53%). In group 2, extracranial volume flow increased from 166 (444) ml/min by 19 (52)%. MCA flow velocities increased from 43 (65) cm/s by 13 (30)%. In group 3, volume flow increased from 159 (467) ml/min by 2 (46)%. Intracranial flow velocities rose from 49 (54) cm/s by 27 (41)%. Volume flow data showed the expected decline in patients with high-grade ICA stenosis and even more pronounced in patients with occlusion of the vessel. Cerebral reserve capacity was less sufficient in patients with a patent OA, despite an additional supply of 30 ml/min, indicating a hemodynamically critical situation.

Vasomotor reactivity in the ophthalmic artery: different from or similar to intracerebral vessels?

OBJECTIVE

In order to evaluate hemodynamic features of ophthalmic arteries in patients with severe carotid artery stenosis, we assessed and compared vasomotor reactivity in the middle cerebral and ophthalmic arteries.

METHODS

Sixty-five patients (25 symptomatic, 40 asymptomatic) with severe (70-99%) internal carotid artery stenosis were studied using transcranial Doppler and the Diamox test.

RESULTS

Vasomotor reactivity was found to be similar in the middle cerebral and ophthalmic arteries on the side of severe carotid stenosis in both symptomatic and asymptomatic patients. In contrast, the vasomotor reactivity of the ophthalmic arteries was significantly different from that of the middle cerebral arteries on the side of the normal or the non-significantly stenotic side of the internal carotid artery.

CONCLUSIONS

These data suggest a specific autoregulative response of the ophthalmic artery compared to that of the middle cerebral artery and may shed light on the role of the ophthalmic artery in oculovascular hemodynamics.

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.

Uterine and cerebral vascularization in postmenopausal women treated with hormone-replacement therapy

The effects of hormone-replacement therapy on the Doppler flow parameters of the ophthalmic artery in postmenopausal women were studied and compared with those registered at the level of the internal carotid and uterine arteries. Fifty-seven postmenopausal patients were submitted to continuous estradiol transdermal supplementation and 12-day courses of medroxyprogesterone acetate. During the estrogen phase of hormone-replacement therapy all patients underwent (at 1, 3 and 6 months after the beginning of hormone-replacement therapy) transvaginal ultrasonographic evaluation of the pelvic organs and of endometrial thickness. On the same day, they underwent color Doppler analysis of the blood flow impedance of the uterine, internal carotid and ophthalmic arteries. Estradiol plasma concentrations were assayed on the day that ultrasonographic and Doppler examinations took place. The pulsatility index of all the arteries improved, from baseline values, during the therapy and attained stable values compared to those after the first month of treatment. Furthermore, at the level of the internal carotid and ophthalmic arteries, a significant increase of the peak systolic blood flow velocity (Vmax) was observed over the 6 months of therapy. Doppler studies of the ophthalmic artery are capable of affording specific and precise pathophysiologic information to assess peripheral intracranial blood flow variations. Furthermore, such studies may be useful in monitoring hormone-replacement therapy effects on cerebral perfusion.