Ocular and orbital blood flow in patients with essential hypertension treated with trandolapril

Orbital and ocular perfusion in thyroid eye disease

Thyroid eye disease (TED) is characterized by enlargement of extraocular muscles, an increase in retrobulbar fat, orbital fibrosis, and fluctuations in plasma thyroid hormone levels in most patients, often associated with raised autoantibody titers. The occurrence of orbital space conflict compromises the orbital perfusion, unchecked progression of which results in irreversible loss of visual acuity and visual fields. The quantitative assessment of orbital perfusion can be done by measurement of blood flow velocities in the superior ophthalmic vein (SOV), ophthalmic artery (OA), central retinal artery (CRA), and posterior ciliary artery by color Doppler imaging. The retinal and choroidal microvasculature is studied by optical coherence tomography and optical coherence tomography angiography. The orbital and ocular perfusion fluctuates during the course of TED. Orbital congestion is reflected by the reduction or reversal of SOV flow and an increase in subfoveal choroidal thickness. The active phase is characterized by high blood flow velocities of the OA and CRA. The onset of dysthyroid optic neuropathy is associated with reduced arterial perfusion and reduction in parafoveal and peripapillary vascular density. Orbital decompression improves the SOV flow and decreases the resistivity index of CRA. Sequential evaluation of orbital hemodynamic changes can thus supplement the clinical scoring systems for monitoring and planning intervention in TED.

Physiological changes in retinal layers thicknesses measured with swept source optical coherence tomography

PURPOSE

To evaluate the physiological changes related with age of all retinal layers thickness measurements in macular and peripapillary areas in healthy eyes.

METHODS

Wide protocol scan (with a field of view of 12x9 cm) from Triton SS-OCT instrument (Topcon Corporation, Japan) was performed 463 heathy eyes from 463 healthy controls. This protocol allows to measure the thickness of the following layers: Retina, Retinal nerve fiber layer (RNFL), Ganglion cell layer (GCL +), GCL++ and choroid. In those layers, mean thickness was compared in four groups of ages: Group 1 (71 healthy subjects aged between 20 and 34 years); Group 2 (65 individuals aged 35-49 years), Group 3 (230 healthy controls aged 50-64 years) and Group 4 (97 healthy subjects aged 65-79 years).

RESULTS

The most significant thinning of all retinal layers occurs particularly in the transition from group 2 to group 3, especially in temporal superior quadrant at RNFL, GCL++ and retinal layers (p≤0.001), and temporal superior, temporal inferior, and temporal half in choroid layer (p<0.001). Curiously group 2 when compared with group 1 presents a significant thickening of RNFL in temporal superior quadrant (p = 0.001), inferior (p<0.001) and temporal (p = 0.001) halves, and also in nasal half in choroid layer (p = 0.001).

CONCLUSIONS

Excepting the RNFL, which shows a thickening until the third decade of life, the rest of the layers seem to have a physiological progressive thinning.

Age-related changes in retrobulbar circulation: a literature review

Introduction

The advances in research methods used in ophthalmology allow for an increasingly accurate examination of the eyes, as well as the morphology and function of the vessels. Colour Doppler imaging is still the first-line method for the analysis of parameters of retrobulbar circulation. Therefore, the aim of this work was to present the current state of knowledge about anatomical and functional age-related changes in retrobulbar arteries.

Methods

A literature search was performed mainly based on the PubMed database.

Results

The anatomy of retrobulbar arteries, histological background of age-related vascular changes, age-related changes in retrobulbar blood flow in the ophthalmic artery, central retinal artery, short posterior ciliary arteries, and the reference values for the age-dependent retrobulbar circulation parameters measured by colour Doppler imaging are discussed in this review.

Conclusion

The age of the subject should always be taken into account when interpreting the parameters of retrobulbar blood flow measured by colour Doppler imaging.

Usefulness of color Doppler imaging of orbital arteries in young hypertensive patients

Color Doppler imaging (CDI) is an established method for investigating ocular blood flow characteristics, and several blood flow parameters can be obtained from the velocity wave. This study evaluated CDI parameters in hypertensive subjects by measuring flow velocities, resistive index, and the pulsatility index of ocular arteries. One hundred young hypertensive patients and 50 age- and gender-matched healthy controls were recruited for the study. CDI parameters of the ophthalmic artery, central retinal artery, and posterior ciliary artery were measured in all subjects. Doppler index cutoff points were calculated using area under the curve with 95% confidence intervals. Results showed that Doppler parameters were significantly higher in subjects diagnosed with hypertension in the young compared to controls.

Peripapillary Choroidal Thickness and Retinal Nerve Fiber Layer in Untreated Patients with Obstructive Sleep Apnea-Hypopnea Syndrome: A Case-Control Study

PURPOSE

To evaluate peripapillary choroidal thickness (PPCT), central macular choroidal thickness (CMCT), and retinal nerve fiber layer (RNFL) thickness in untreated patients with obstructive sleep apnea-hypopnea syndrome (OSAHS).

METHODS

This prospective, randomized, and comparative study was conducted in a university ophthalmology clinic. 106 eyes of 106 patients with OSAHS and 44 eyes of 44 healthy individuals were evaluated in this study. Only right eyes were evaluated. The patients with OSAHS were divided into three groups as mild (group 1), moderate (group 2), and severe (group 3) according to apnea-hypopnea index. The PPCT, CMCT, and RNFL measurements were performed by using spectral domain optical coherence tomography with enhanced depth imaging technique. The main parameters assessed were PPCT-Temporal, PPCT-Superior, PPCT-Nasal, PPCT-Inferior quadrants, CMCT, and RNFL thicknesses.

RESULTS

The PPCT of all quadrants was significantly thicker in the control group compared with the moderate and severe subgroups of OSAHS (p < 0.05). The PPCT-Superior and PPCT-Temporal were significantly thinner in the mild subgroup compared with the control group (p = 0.003 and p = 0.028, respectively). There was no difference between the control and mild groups regarding the RNFL thicknesses except nasal RNFL and inferotemporal RNFL which are thinner in the mild group. The RNFL thicknesses of all quadrants were significantly thicker in the control group compared with moderate and severe subgroups (p < 0.05). The CMCT was significantly thicker in the control group compared with all subgroups of OSAHS (p < 0.05).

CONCLUSIONS

In OSAHS patients, PPCT, CMCT, and RNFL were significantly thinner compared with the control group. These results may explain why OSAHS patients are prone to normotensive glaucoma.

Evaluation of resistive index using color Doppler imaging of orbital arteries in geriatric patients with hypertension

Background and Aim:

Resistive index (RI) is an indirect measurement of blood flow resistance that can be used to evaluate vascular damage in ophthalmologic disease. The purpose of this study was to evaluate the association between RI values of orbital arteries using the color Doppler imaging (CDI) in geriatric hypertensive patients with or without retinopathy.

Setting and Design:

Designed as a cross-sectional study.

Materials and Methods:

We evaluated 60 geriatric patients with hypertension (Group 1) and 30 healthy subjects (Group 2). Further, the patients with hypertension were grouped into two: Group 1a consisted of patients with retinopathy (n = 30), and group 1b consisted of patients without retinopathy (n = 30). The mean RI values of ophthalmic artery (OA), central retinal artery (CRA), and posterior ciliary artery (PCA) were measured using CDI.

Results:

Compared to group 2, group 1 had significantly higher mean resistive index of PCA levels (P = 0.017), whereas there were no statistical difference in mean resistive indexes of OA and CRA (both P > 0.05). Besides, there were no statistical difference in mean resistive indexes of OA, CRA, and PCA between the group 1a and group 1b (P > 0.05 for all). Mean resistive indexes of OA, CRA, and PCA were significantly correlated with the duration of hypertension (r = 0.268, P = 0.038; r = 0.315, P = 0.014; r = 0.324, P = 0.012, respectively).

Conclusions:

Our study indicates that RI might be a useful marker for the ocular hemodynamic of retinal vessels, provides morphologic and vascular information in hypertension and hypertensive retinopathy.

Comparison of intraocular pressure, blood pressure, ocular perfusion pressure and blood flow fluctuations during dorzolamide versus timolol add-on therapy in prostaglandin analogue treated glaucoma subjects

Objective: To compare the effects of dorzolamide and timolol add-on therapy in open-angle glaucoma (OAG) patients previously treated with prostaglandin analogue (Pg), by evaluating fluctuations in the intraocular (IOP), blood (BP), ocular perfusion pressures (OPP) and retrobulbar blood flow (RBF) parameters. Methods: 35 OAG patients (35 eyes), 31 women (88.6%) age 63.3 (8.9) years were evaluated in a 3 month randomized, cross-over, single-masked study. During the experiments BP, heart rate, IOP and OPP were assessed 4 times per day (8–12–16–20 h). RBF was measured twice per day (8–20 h) using Color Doppler imaging in the ophthalmic (OA), central retinal (CRA), nasal (nSPCA) and temporal (tSPCA) posterior ciliary arteries. In each vessel, peak systolic velocity (PSV) and end-diastolic velocity (EDV) were assessed and vascular resistance (RI) calculated. Results: Both add-on therapies lowered IOP in a statistically significant manner from 15.7 ± 2.4 mmHg at latanoprost baseline to 14.9 ± 2.2 mmHg using dorzolamide (p < 0.001) and 14.2 ± 1.9 mmHg using timolol (p < 0.001). The IOP lowering effect was statistically significant at 20 h, favoring timolol as compared to dorzolamide (1.4 ± 2.4 vs. 0.2 ± 2.1 mmHg), (p < 0.05). Dorzolamide add-on therapy showed smaller IOP (2.0 ± 1.4), SPP (13.3 ± 7.9), systolic BP (13.5 ± 8.7) and diastolic BP (8.4 ± 5.4) fluctuations as compared to both latanoprost baseline or timolol add-on therapies. Higher difference between morning and evening BP was correlated to decreased evening CRA EDV in the timolol group (c = −0.41; p = 0.01). With increased MAP in the morning or evening hours, we found increased evening OA RI in timolol add-on group (c = 0.400, p = 0.02; c = 0.513, p = 0.002 accordingly). Higher MAP fluctuations were related to impaired RBF parameters during evening hours-decreased CRA EDV (c = −0.408; p = 0.01), increased CRA RI (c = 0.576; p < 0.001) and tSPCA RI (c = 0.356; p = 0.04) in the dorzolamide group and increased nSPCA RI (c = 0.351; p = 0.04) in the timolol add-on group. OPP fluctuations correlated with increased nSPCA RI (c = 0.453; p = 0.006) in the timolol group. OPP fluctuations were not related to IOP fluctuations in both add-on therapies (p < 0.05). Conclusions: Both dorzolamide and timolol add-on therapies lowered IOP in a statistically significant fashion dorzolamide add-on therapy showed lower fluctuations in IOP, SPP and BP. Higher variability of daytime OPP led to impaired RBF parameters in the evening.

Effects of the time of antihypertensive drugs administration on the stage of primary open-angle glaucoma in patients with arterial hypertension

Many patients with glaucoma suffer from arterial hypertension (AH). It has been proved that both AH and low blood pressure (BP) at night are important vascular risk factors for primary open-angle glaucoma (POAG). The aims of this study were to assess the severity of pathological changes within the optic nerve and characteristics of blood flow in selected arteries of the eyeball and orbit in patients with POAG and controlled hypertension, in relation to the time of hypotensive drugs administration. Eighty-eight patients with POAG and treated, controlled hypertension were examined. The patients were divided into two subgroups, consisting of group A (n = 43), in whom hypotensive drugs were dosed only in the morning and group B (n = 45), in whom hypotensive drugs were also taken in the evening. In patients who were taking hypotensive drugs also in the evening (group B), there was a statistically significant lower mean perfusion pressure at night, a greater visual field loss and reduced amplitude of evoked potentials. Our analysis showed significantly worse changes in the parameters relating to the optic nerve in patients taking hypertensive medicines in the evening and also significantly lower perfusion pressures at night.

Effects of bisoprolol and cilazapril on the central retinal artery blood flow in patients with essential hypertension--preliminary results

BACKGROUND

A growing body of evidence suggests that effective blood pressure reduction may inhibit the progression of microvascular damage in patients with essential arterial hypertension. However, the potential influence of anti-hypertensive drugs on ocular circulation has not been studied sufficiently.

PURPOSE

The aim of our study was to evaluate the effects of anti-hypertensive therapy on blood flow in the central retinal artery in patients with systemic arterial hypertension.

MATERIAL AND METHODS

Twenty patients with essential arterial hypertension, aged 32-46 years, were examined with Doppler ultrasonography (10 MHz ultrasound probe). Blood flow velocities, pulsatility, and vascular resistance were determined before and 3 hours after systemic application of either bisoprolol 5 mg or cilazapril 2.5 mg.

RESULTS

Administered bisoprolol significantly decreased maximum (9.8 ± 0.5 cm/s versus 8.5 ± 0.6 cm/s; P < 0.05) and minimum (2.75 ± 0.19 cm/s versus 1.75 ± 0.27 cm/s; P < 0.02) velocity, increased the Pourcellot's index (0.71 to 0.79; P < 0.05) in central retinal artery. There were no statistically significant changes in central retinal artery blood flow after administration of cilazapril.

CONCLUSION

Systemic application of beta-blockers may unfavourably disturb the ocular blood flow.

Kidney flow and function in hypertension: protective effects of pycnogenol in hypertensive participants--a controlled study

This study evaluated the effects of Pycnogenol as an adjunct to angiotensin-converting enzyme (ACE)-inhibitor ramipril treatment of hypertensive patients presenting with early signs of renal function problems. One group of 26 patients was medicated with 10 mg ramipril per day only; a second group of 29 patients took Pycnogenol in addition to the ACE inhibitor over a period of 6 months. At trial end, a lowered systolic and diastolic blood pressure was found in both groups, with a significant further reduction of diastolic pressure in the group given Pycnogenol in addition to ramipril. The major aim of this study was the investigation of kidney-protective effects of Pycnogenol. Urinary albumin decreased from 87 +/- 23 to 64 +/- 16 mg/d with ramipril only. Additional Pycnogenol lowered albumin significantly better from 91 +/- 25 to 39 +/- 13 mg/day (P < .05). In both groups, serum creatinine was lowered; however, only in the combination treatment group did the effect reached statistical significance. In both groups, CRP levels decreased from 2.1 to 1.8 with ramipril and from 2.2 to 1.1 with the ramipril-Pycnogenol combination; the latter reached statistical significance. Kidney cortical flow velocity was investigated by Doppler color duplex ultrasonography. Both systolic and diastolic flow velocities increased significantly after 6 months medication with ramipril. The addition of Pycnogenol to the regimen statistically significantly further enhanced kidney cortical flow velocities, by 8% for diastolic flow and 12% for systolic flow, relative to values found for the group taking ramipril only. The protective effects of Pycnogenol for initial kidney damage found in this study warrant further research with a larger number of patients and over a longer period of time.

The effects of antiglaucoma and systemic medications on ocular blood flow

Based on the body of evidence implicating ocular blood flow disturbances in the pathogenesis of glaucoma, there is great interest in the investigation of the effects of antiglaucoma drugs and systemic medications on the various ocular vascular beds. The primary aim of this article was to review the current data available on the effects of antiglaucoma drugs and systemic medications on ocular blood flow. We performed a literature search in November 2002, which consisted of a textword search in MEDLINE for the years 1968-2002. The results of this review suggest that there is a severe lack of well-designed long-term studies investigating the effects of antiglaucoma and systemic medications on ocular blood flow in glaucomatous patients. However, among the 136 articles dealing with the effect of antiglaucoma drugs on ocular blood flow, only 36 (26.5%) investigated the effects of medications on glaucoma patients. Among these 36 articles, only 3 (8.3%) were long-term studies, and only 16 (44.4%) were double-masked, randomized, prospective trials. Among the 33 articles describing the effects of systemic medications on ocular blood flow, only 11 (33.3%) investigated glaucoma patients, of which only one (9.1%) was a double-masked, randomized, prospective trial. Based on this preliminary data, we would intimate that few antiglaucoma medications have the potential to directly improve ocular blood flow. Unoprostone appears to have a reproducible antiendothelin-1 effect, betaxolol may exert a calcium-channel blocker action, apraclonidine consistently leads to anterior segment vasoconstriction, and carbonic anhydrase inhibitors seem to accelerate the retinal circulation. Longitudinal, prospective, randomized trials are needed to investigate the effects of vasoactive substances with no hypotensive effect on the progression of glaucoma.

Effects of hypertension and antihypertensive treatment on retrobulbar circulation detected on Doppler sonography

OBJECTIVE

To study the effect of antihypertensive drugs in essential hypertension and in the central retinal, posterior ciliary, and ophthalmic arteries by using Doppler sonography.

METHODS

Thirty patients with essential hypertension and 32 control subjects were enrolled in the study. The pulsatility and resistive indices were evaluated in the central retinal, posterior ciliary, and ophthalmic arteries before and 2 months after treatment with antihypertensive drugs as well as in the control group. The pulsatility and resistive index values for each artery in each group were compared statistically.

RESULTS

There were significant differences in the retrobulbar pulsatility and resistive index values in each artery among the patients with initially diagnosed hypertension and the control group (P < .05). There were significant reductions in the resistive and pulsatility index values of the posterior ciliary and ophthalmic arteries after treatment (P < .05). For the ophthalmic artery, posttreatment pulsatility and resistive index values did not reach the level of flow measured in the control subjects.

CONCLUSIONS

The alteration of Doppler parameters of medication-free patients with hypertension may result from a peripheral vasospasm in the retrobulbar circulation, and the improvement in the Doppler parameters with oral antihypertensive drugs may indicate the importance of early diagnosis in ameliorating hypertension-induced retrobulbar circulation changes.

Central retinal artery Doppler flow parameters reflect the severity of cerebral small-vessel disease

BACKGROUND AND PURPOSE

We investigated the usefulness of central retinal artery (CRA) Doppler flowmetry in patients with cerebral small-vessel disease (SVD).

METHODS

CRA Doppler flowmetry was performed in 103 SVD patients who underwent MRI. Sixty-four adjusted control subjects were also registered. We assessed average CRA flow parameter values for both eyes with the clinical and MRI findings.

RESULTS

Each Doppler flowmetry was performed within 5 minutes. Patients with SVD had significantly lower end-diastolic and mean velocities of the CRA than control subjects; they also had higher pulsatility and resistive indexes. Multivariate analysis showed that the number of small infarcts was an independent predictor of peak systolic and mean velocities. Grade of periventricular hyperintensities was an additional independent predictor of peak systolic and mean velocities, whereas the number of small infarcts was predictive of end-diastolic velocity.

CONCLUSIONS

Flow parameters may be useful for the quantitative assessment of SVD severity.

The effects of latanoprost and brimonidine on blood flow velocity of the retrobulbar vessels: a 3-month clinical trial

OBJECTIVE

To investigate the effects of topical latanoprost 0.005% and topical brimonidine tartrate 0.2% on retrobulbar blood flow in patients with primary open-angle glaucoma (POAG) and ocular hypertension (OHT).

METHODS

Forty-one consecutive patients with POAG and OHT were enrolled in this prospective, open-label, randomized, parallel study. Patients received either latanoprost 0.005% or brimonidine 0.2% for 3 months. Baseline retrobulbar blood flow measurements of the ophthalmic artery, central retinal artery and temporal short posterior ciliary artery were taken using colour Doppler imaging ultrasound, concurrently with systemic blood pressure, heart rate, ocular perfusion pressure and intraocular pressure (IOP) measurements. These measurements were repeated after 3 months.

RESULTS

Both latanoprost and brimonidine significantly reduced IOP (p < 0.05). While there was a statistically significant increase in peak systolic velocity of the ophthalmic artery, no significant change was observed in the other vessels with latanoprost treatment (p < 0.05). Topical brimonidine did not significantly alter flow velocities or resistive indices in the retrobulbar vessels after 3 months.

CONCLUSION

Topical latanoprost and brimonidine significantly reduced IOP in patients with POAG and OHT without causing significant haemodynamic alterations in the retrobulbar vessels.

Trandolapril: a newer angiotensin-converting enzyme inhibitor

BACKGROUND

Trandolapril is a newer angiotensin-converting enzyme (ACE) inhibitor that is approved by the US Food and Drug Administration for the treatment of hypertension and for use in stable patients who have evidence of left ventricular (LV) systolic dysfunction or symptoms of chronic heart failure within the first 2 days after an acute myocardial infarction (AMI). The fixed-dose combination of trandolapril and verapamil extended release (ER) is approved for the treatment of hypertension only.

OBJECTIVE

The purpose of this article was to review the pharmacology, pharmacokinetics, clinical efficacy, and safety profile of trandolapril as monotherapy and in fixed-dose combination with verapamil ER.

METHODS

Relevant studies were identified through a MEDLINE/PubMed search of the English-language literature published between January 1983 and August 2002 and a review of the bibliographies of identified articles.

RESULTS

Trandolapril has a sufficient duration of inhibition of plasma ACE activity to allow once-daily dosing. It is converted by esterases to the active trandolaprilat metabolite, with mean terminal disposition half-lives of < 1 and approximately 75 hours for the prodrug and metabolite, respectively. In comparative trials in the management of hypertension, trandolapril 1 to 4 mg/d was statistically indistinguishable from or superior to captopril 100 mg/d, enalapril 10 or 20 mg/d, hydrochlorothiazide (HCTZ) 25 mg/d, nifedipine ER 30 or 40 mg/d, nitrendipine 20 mg/d, perindopril 4 mg/d, and verapamil ER 120 to 240 mg/d. In the Trandolapril Cardiac Evaluation, trandolapril also significantly reduced all-cause mortality, cardiovascular mortality, sudden death, and progression to severe chronic heart failure in patients with evidence of LV systolic dysfunction after AMI. In comparative trials in the management of hypertension, the combination of trandolapril 1 or 2 mg/d and verapamil ER 180 mg/d was statistically indistinguishable from or superior to the combinations of atenolol 50 or 100 mg/d plus chlorthalidone 12.5 or 25 mg/d, captopril 50 mg/d plus HCTZ 25 mg/d, lisinopril 20 mg/d plus HCTZ 12.5 mg/d, and metoprolol 100 mg/d plus HCTZ 12.5 mg/d. The most common adverse effects of trandolapril monotherapy in clinical trials of < or = 1 year's duration included cough, dizziness, and diarrhea (frequency < or = 1.9%). The most common adverse effects of trandolapril/verapamil ER therapy in clinical trials of < or = 1 year's duration included first-degree atrioventricular block, bradycardia, constipation, cough, diarrhea, dizziness, fatigue, and dyspnea (frequency < or = 4.6%). Based on the literature search, there are no published pharmacoeconomic evaluations of trandolapril alone or combined with verapamil ER in the US health care setting.

CONCLUSIONS

Based on the literature, trandolapril is a well-tolerated and effective antihypertensive agent, whether used alone or in combination with verapamil ER. These products may be valuable in patients with LV systolic dysfunction after AMI, although the combination product is approved for the management of hypertension only.

Effect of hypertension and candesartan on the blood flow velocity of the extraocular vessels in hypertensive patients

OBJECTIVE

To define alterations in the blood flow velocities of the ophthalmic artery (OA), central retinal artery (CRA), posterior ciliary artery (PCA) in essential hypertension and to evaluate the effect of a new antihypertensive drug, candesartan which is an angiotensin II receptor antagonist, on the blood flow velocity in hypertensive patients.

METHODS

Blood flow velocity and resistive index (RI) of the OA, CRA, and PCA were measured in 22 hypertensive patients off medication and 15 controls by color Doppler imaging. After treatment with candesartan, blood flow velocity and RI were again measured in the hypertensive patients.

RESULTS

In controls (n=15), the OA had a mean peak systolic flow velocity (PSFV) of 48.1+/-2.6 cm/s, mean end diastolic flow velocity (EDFV) of 16+/-1.0 cm/s, and RI of 0.65+/-0.01; the CRA had a PSFV of 20.8+/-0.4 cm/s, EDFV of 9.4+/-0.3 cm/s, and RI of 0.54+/-0.01; the PCA had a PSFV of 23.6+/-0.7 cm/s, EDFV of 11.2+/-0.3 cm/s, and RI of 0.52+/-0.01. There was a significant decrease in the PSFV and EDFV of the vessels in the medication free hypertensive patients when compared with controls (P<0.05). In the hypertensive patients off medication (n=22), the OA had a PSFV of 29.4+/-1.2 cm/s, EDFV of 10.4+/-0.5 cm/s, and RI of 0.71+/-0.01; the CRA had a PSFV of 15.1+/-0.6 cm/s, EDFV of 5.4+/-0.3 cm/s, and RI of 0.65+/-0.02; the PCA had a PSFV of 17.2+/-0.6 cm/s, EDFV of 6.7+/-0.3 cm/s, and RI of 0.61+/-0.01. RI measured in the OA, CRA, PCA were significantly increased in the hypertensive patients when compared with the controls (P<0.05). In hypertensive patients after medication (n=22), OA had a PSFV of 38.3+/-2.5 cm/s, EDFV of 12.3+/-0.7 cm/s, and RI of 0.68+/-0.01; CRA had a PSFV of 19.2+/-0.5 cm/s, EDFV of 7.8+/-0.3 cm/s, and RI of 0.59+/-0.01; PCA had a PSFV of 20.8+/-0.8 cm/s, EDFV of 9.2+/-0.4 cm/s, and RI of 0.56+/-0.01. There was a significant increase in the blood flow velocities of the OA, CRA, PCA (P<0.05) and significant decrease in the RI values in the treated hypertensive patients when compared with the controls (P<0.05). But blood flow velocities and RI values did not reach the control level.

CONCLUSION

The increase in the RI values and the decrease in the blood flow velocity of extraocular vessels in the hypertensive patients are thought to be caused by increased peripheral resistance in the vessels of the eye and orbit. Although, it increases blood flow velocity and decreases RI significantly, candesartan treatment in the hypertensive patients cannot increase blood flow velocity and decrease RI to the control level.

Epilepsy patients treated with vigabatrin exhibit reduced ocular blood flow

BACKGROUND/AIM

Reduced cerebral blood flow and decreased glucose metabolism have been identified in epilepsy patients receiving vigabatrin. It is likely that such a change may extend to the eye and may be linked to previously reported irreversible visual field defects. The aim of this study was to determine whether patients who have undergone anti-epileptic drug (AED) therapy with vigabatrin have altered ocular haemodynamics.

METHODS

The study cohort comprised 11 normal subjects (mean age 42.6 (SD 12.7) years and 17 epilepsy patients, of which 10 were either currently or previously treated with vigabatrin (38.6 (11.7) years) and seven were treated with AEDs excluding vigabatrin (46.0 (9.8) years). The three groups were matched at baseline for pulse rate, diastolic and systolic blood pressure, and intraocular pressure (IOP). At a single visit, the ocular blood flow analyser (OBFA; Paradigm Medical Instruments Inc, UT, USA) was used to measure pulsatile ocular blood flow (POBF) and pulse amplitude (PA) in each eye of all subjects. One way ANCOVA (with age as a covariate) was used to identify differences in POBF and PA between the groups. For the vigabatrin group only, Pearson's product moment correlation coefficient was used to explore potential interactions between ocular blood flow parameters and cumulative vigabatrin dose, duration, and maximum dose.

RESULTS

Both the vigabatrin treated epilepsy group and conventionally treated epilepsy group exhibited significantly reduced POBF (p=<0.001, p=0.040) and PA (p=<0.001, p=0.005) compared to normal subjects. Patients treated with vigabatrin exhibited a further reduction in POBF (p=0.046) and PA (p=0.034) compared to conventionally treated epilepsy patients. No significant correlations were found between drug dosage and POBF and PA for the vigabatrin treated epilepsy group.

CONCLUSIONS

A significant reduction in POBF and PA is apparent in epilepsy patients treated with AEDs when compared to normal subjects. A further reduction in POBF and PA is apparent between vigabatrin treated and conventionally treated patients. The reduction in ocular perfusion, which is more pronounced in patients previously treated with vigabatrin, may have implications in the impairment of visual function associated with the drug.

The effect of dehydration and fasting on ocular blood flow

PURPOSE

To investigate the effects of dehydration and fasting on retrobulbar-vessel blood velocity in healthy subjects.

METHODS

Twenty-eight eyes of 28 normal subjects without ocular disease were enrolled in this study. Each subject had a baseline color-Doppler imaging ultrasound of the central retinal artery, temporal short posterior ciliary arteries, and ophthalmic artery after 14 hours of religious fasting and dehydration. The first measurements were performed in the fasting conditions. The mean blood flow velocities and resistive index were measured in each artery. One month after the fasting period, color-Doppler imaging measurements were performed in nonfasting conditions. Blood pressure, heart rate, and intraocular pressure were measured before color-Doppler imaging measurements in both the fasting and nonfasting conditions.

RESULTS

Although systolic/diastolic blood pressure, heart rate, and intraocular pressure (111.78 +/- 8.18/76.42 +/- 5.75 mm Hg, 71.00 +/- 2.88 beats/min, and 12.71 +/- 2.25 mm Hg) were higher in nonfasting conditions (112.32 +/- 7.97/78.98 +/- 5.50 mm Hg, 70.71 +/- 2.77 beats/min, and 13.14 +/- 2.62 mm Hg, respectively), differences were not statistically significant. A statistically significant increase in peak systolic velocity in the ophthalmic artery, central retinal artery, and temporal short posterior ciliary artery was noted at the second measurements. A peak systolic velocity value of 48.90 +/- 14.66 cm/sec in the ophthalmic artery increased to 58.28 +/- 14.65 cm/sec in the nonfasting conditions ( < 0.05). A peak systolic velocity value of 16.88 +/- 4.30 cm/sec and an end diastolic velocity of 6.69 +/- 2.15 cm/sec in the central retinal artery increased to 24.24 +/- 6.45 cm/sec and 9.32 +/- 3.08 cm/sec, respectively, was recorded in the nonfasting and nondehydration condition ( < 0.05). Peak systolic velocity measurement of 23.42 +/- 6.19 cm/sec in temporal short posterior ciliary artery increased to 26.68 +/- 7.52 cm/sec at the second measurement ( < 0.05). The only significant change observed in the resistive index measurements was an increase in the ophthalmic artery resistive index in the nonfasting conditions ( < 0.05).

CONCLUSIONS

Color-Doppler measurement may vary significantly in conditions of fasting and dehydration conditions compared with hydrated conditions. Therefore, the fasting and dehydration conditions should be considered when interpreting color-Doppler imaging results and comparing different groups of diseased or healthy subjects.

Choroidal circulation in diabetic patients

PURPOSE

To evaluate choroidal circulatory changes in diabetic patients with and without background diabetic retinopathy (BDR) by measuring the retrobulbar circulation with colour Doppler imaging (CDI).

METHODS

CDI was used to measure circulatory parameters of the PCA (posterior ciliary artery), CRA (central retinal artery), OA (ophthalmic artery) and the respective veins in 73 diabetic patients and 22 controls in a sitting posture. Among the diabetic patients, 38 patients were without diabetic retinopathy (NDR) and 35 had BDR. A non-parametric Kruskal-Wallis test with a Dunn correction was used for data analysis.

RESULTS

End-diastolic velocity (EDV) in the PCA was decreased (2.55+/-0.80 cm/s) and resistivity index (RI) in the PCA was increased (0.70+/-0.08) in BDR patients compared with the control patients' EDV (3.23+/-1.08 cm/s, p = 0.01) and RI (0.62+/-0.06, p = 0.0003). RI in the CRA was significantly higher in the BDR group (0.74+/-0.09) than in the control group (0.68+/-0.08, p = 0.006). RI in the OA was significantly higher in the BDR group (0.87+/-0.06) compared both with the NDR group (0.83+/-0.07) and with the control group (0.81+/-0.06; p = 0.007, p = 0.004). NDR patients had a significantly higher RI in the PCA (0.67+/-0.08) than control patients (0.62+/-0.06, p = 0.01, while the CRA RI (0.71+/-0.09) did not show significant differences from the control group (0.69+/-0.08, p = 0.32). Decreased EDV in the CRA was detected in NDR patients (2.16+/-0.76 cm/s) compared with the controls (2.72+/-0.92 cm/s, p = 0.007).

CONCLUSION

The results from this study suggest that not only the retinal but also the choroidal circulation is affected in NDR and BDR patients.

The impact of glaucoma medication on parameters of ocular perfusion

Whereas intraocular pressure is considered a major risk factor in glaucoma, growing evidence now indicates that ocular ischemia plays a major role too. By virtue of this and because many existing medications are able to interact with vasculature, altering ocular blood flow, it is essential that current and future medications for glaucoma be evaluated for their effect on ocular circulation. The authors review published papers examining the effect of topical and some systemic medications on ocular blood flow, focusing mostly on data from the human eye. The authors provide a comprehensive review on the effect of subclasses of medications (eg, carbonic anhydrase inhibitors, beta-blockers, alpha-adrenergic agonists, and prostaglandin analogues on optic nerve head, and on retinal, choroidal, and retrobulbar circulation. The various claims for enhancements or reduction of ocular circulation within each class of medication are reviewed and evaluated.

Pressure and microcirculatory effects of treatment with lercanidipine in hypertensive patients and in vascular patients with hypertension

The aim of this study was to evaluate the macrocirculatory and microcirculatory effects of treatment with lercanidipine, a new antihypertensive agent acting both on blood pressure and microcirculation in patients with moderate essential hypertension and without vascular disease and in patient with hypertension and vascular disease. In hypertensive subjects target-organ damage associated with high blood pressure may now be objectively documented by noninvasive tests. These alterations constitute a model to evaluate not only the pressure effects of antihypertensive treatment but also the normalization of the peripheral microcirculatory network. With color duplex scanning, flow velocity in the central retinal artery and retinal flow velocity can be measured and with use of laser-Doppler-flowmetry, it is also possible to evaluate microcirculation alterations in hypertensive subjects. These evaluation methods are completely noninvasive and may be used to assess the microcirculatory effects of antihypertensive drugs.