Role of rheologic factors in patients with acute central retinal vein occlusion

Association of Retinal Vein Occlusion With Serum Osmolality and Hydration Status

BACKGROUND AND OBJECTIVE

The aim of this study was to evaluate serum osmolality and hydration status in patients with retinal vein occlusion (RVO).

PATIENTS AND METHODS

This cross-sectional study consisted of 79 patients with RVO and 81 age- and sex-matched peers without ocular disease. Data were collected from patient records and included a comprehensive ophthalmological examination, laboratory data of fasting blood test results, and internal medicine outpatient examination. Complete blood count and levels of fasting glucose, sodium, blood urea nitrogen (BUN), creatinine, triglyceride, low-density lipoprotein, high-density lipoprotein, HbA1c, and serum osmolality were evaluated. BUN/creatinine ratios were calculated.

RESULTS

Mean serum sodium and serum osmolality levels were 142.53 ± 2.13 and 139.74 ± 2.16 mEq/L and 286.58 ± 4.40 and 280.57 ± 4.39 mOsmol/kg H2O in the RVO and control groups, respectively. Serum osmolality and serum sodium levels, and BUN/creatinine ratio were significantly higher in the RVO group than in controls (P < 0.05 for all).

CONCLUSIONS

We found that serum osmolality, sodium levels, and the BUN/creatinine ratio increased significantly in the RVO group. The results suggest dehydration status may affect the genesis of vessel occlusion in RVO. [Ophthalmic Surg Lasers Imaging Retina 2024;55:130-135.].

Red Blood Cells: A Newly Described Partner in Central Retinal Vein Occlusion Pathophysiology?

Central retinal vein occlusion (CRVO) is a frequent retinal disorder inducing blindness due to the occlusion of the central vein of the retina. The primary cause of the occlusion remains to be identified leading to the lack of treatment. To date, current treatments mainly target the complications of the disease and do not target the primary dysfunctions. CRVO pathophysiology seems to be a multifactorial disorder; several studies did attempt to decipher the cellular and molecular mechanisms underlying the vessel obstruction, but no consensual mechanism has been found. The aim of the current review is to give an overview of CRVO pathophysiology and more precisely the role of the erythroid lineage. The review presents emerging data on red blood cell (RBC) functions besides their role as an oxygen transporter and how disturbance of RBC function could impact the whole vascular system. We also aim to gather new evidence of RBC involvement in CRVO occurrence.

Hypertension and multiple cardiovascular risk factors increase the risk for retinal vein occlusions: results from the Gutenberg Retinal Vein Occlusion Study

OBJECTIVE

Although several risk factors for retinal vein occlusion (RVO) are known, what triggers RVO is unclear in many cases. We aimed to evaluate the relevance of multiple risk factors in patients with RVO.

METHODS

The Gutenberg RVO Study is an observational case-control study that assessed thrombophilic, cardiovascular, ophthalmic, and drug-related risk factors in participants with RVO and the same number of matched controls. Conditional logistic regression analysis was chosen to estimate the risk of RVO due to several risk factors.

RESULTS

Of 92 patients with RVO, 46 (50%) had central RVO, 31 (33.7%) had branch RVO, and 15 (16.3) had hemi-RVO. Systemic hypertension was associated with RVO [any RVO: odds ratio (OR): 1.81; 95% confidence interval (CI): 1.14-2.88; branch RVO: OR: 2.56; 95% CI: 1.08-6.10]. The most frequent combinations of risk factors were hypertension with dyslipidemia (33 of 92, 35.9%) and hyperhomocysteinemia and high levels of factor VIII (10 of 92, 10.9%). An increase in the risk sum score by one additional risk factor corresponded to ORs of 1.74 (95% CI: 1.31-2.32) for cardiovascular risk factors, 1.38 (95% CI: 1.04-1.82) for thrombophilic risk factors, and 1.43 (95% CI: 1.20-1.70) for the total number of risk factors for RVO.

CONCLUSION

Cardiovascular risk factors are more important than other risk factors for the presence of RVO. The risk of RVO increased by approximately 40% with any additional risk factor and by 70% with any additional cardiovascular risk factor.

Risk Factors in Central Retinal Vein Occlusion and Activated Protein C Resistance

Introduction

Central retinal vein occlusion (CRVO) tends to be a disease of older individuals, with some known major risk factors, and activated protein C resistance seems to be one of the causes in younger patients. In this study, we reviewed risk factors including activated protein C resistance in a series of patients with CRVO.

Methods

Twenty-four patients with a diagnosis of CRVO presenting either acutely or for a follow-up visit during the study period, were enrolled. Ages ranged between 31 and 83 years (mean 59.7). The risk factors, presence of ischemia, the results of biochemical serological and hematological tests, especially activated protein C resistance (APC-R), were analysed.

Results

In 17 patients (71%) one or more of the following risk factors existed: hypertension, diabetes, oral contraceptive usage, family history of thrombosis, and previous operation. In 40% of the eyes, there were ischemic changes. Serum triglycerides were high in 4 of 21 patients (19%) and cholesterol and urea were high in 10 of 21 patients (19%). APC-R was found in 6 out of 24 patients (25%).

Conclusions

Besides known predisposing factors like hypertension, diabetes, glaucoma and hyperlipidemia, APC-R seems to be a risk factor for CRVO at all ages.

Anterior chamber depth and angle-closure glaucoma after central retinal vein occlusion

Background

The purpose of this study was to report the anterior chamber (AC) depth and the attack of angle-closure glaucoma (ACG) in eyes with the recent onset of central retinal vein occlusion (CRVO).

Methods

This retrospective case series included 24 patients with recent onset of CRVO (within one month of attack) from July 2001 to December 2002. The mean follow-up period of the patients was 46 months (range: 3 to 92 months). AC depth was measured using an ultrasound biomicroscopy. Clinical data, including systemic disorders, intraocular pressure, and visual outcomes were recorded. The main outcome measures were AC depth in the diseased eye and the fellow eye of the same patient and the attack of ACG after CRVO.

Results

The mean AC depth in the diseased eyes was significantly shallower than in the unaffected fellow eyes (2.43 ± 0.45 mm vs. 2.55 ± 0.46 mm; p < 0.001). Four patients (17 %) developed ACG after the onset of CRVO within one month of the CRVO attack. In these four patients, the mean AC depth in the diseased eyes was 1.91 ± 0.21 mm, which was much shallower than the eyes without ACG attack (2.53 ± 0.40 mm).

Conclusions

AC depth is significantly shallower following the onset of CRVO. ACG can occur in patients after the onset of CRVO.

Influence of hemorheological factors on the development of retinal vein occlusion

OBJECTIVE

The aim of this article was to present the influence of hemorheological factors on appearance of Retinal Vein Occlusion (RVO). Article explains which factors predispose to the occurrence of RVO.

STUDY SELECTION

Data presented in the article were collected from both review articles and research articles as well as other sources concerning hemorheology, pharmacology and ophthalmology.

RESULTS

Appearance of RVO is connected with blood viscosity and hemorheological parametres like aggregation of red blood cells, deformability of red blood cells, fibrinogen concentrations and haematocrit, and platelet activity. In the pathogenesis of retinal vein occlusion other risk factors were also indicated: age, systemic diseases and smoking. Such correlation has been indicated in numerous researches which were conducted over the last years. RVO is usually accompanied by macular oedema. RVO may successfully be treated using intravitreal dexamethasone implant.

CONCLUSION

Quick diagnosis and therapy create a possibility for successful treatment. Corticosteroid positive influence on visual acuity improvement has been indicted in two randomized, double-blind controlled studies - CRUISE and BRAVO. In both studies, the improvement of vision has been accompanied by a significant reduction of oedema in the vicinity of macula, reflected in the central retinal thickness.

Red blood cell phosphatidylserine exposure is responsible for increased erythrocyte adhesion to endothelium in central retinal vein occlusion

BACKGROUND

Retinal vein occlusion (RVO) is a common cause of permanent loss of vision. The pathophysiology is uncertain, although enhanced erythrocyte aggregation and blood hyperviscosity have been observed. Increased red blood cell (RBC) adhesion has been associated with vascular complications in several diseases, such as sickle cell anemia, diabetes mellitus or polycythemia vera.

OBJECTIVES

To measure RBC adhesion to endothelial cells in RVO and to explore the molecular basis of the adhesion process.

PATIENTS AND METHODS

We assessed RBC adhesion to endothelial cells and adhesion molecule expression among 32 patients with RVO. Patients with disease known to alter RBC adhesion were excluded (n = 8), and further investigation was conducted in 20 patients with central retinal vein occlusion (CRVO) and four patients with retinal artery occlusion (RAO), compared with 25 normal subjects.

RESULTS

Under static conditions, adhesion of CRVO RBC was increased (135 ± 7 × 10(2) mm(-2)) compared with RAO RBC (63 ± 5 × 10(2) mm(-2)) (P < 0.01) and normal control RBC (37 ± 3 × 10(2) mm(-2)) (P < 0.001). Under flow conditions, CRVO RBC adhered in greater numbers than normal RBC (P < 0.001). Phosphatidylserine (PS) expression on CRVO RBC was 2.4-fold higher than controls and correlated with RBC adhesion (P = 0.001). In static conditions, specific antibodies against PS receptor and annexin V inhibited RBC adhesion. In flow conditions, the inhibitory effect was in the same range with antibodies but was 2-fold higher with annexin V.

CONCLUSION

Increased CRVO RBC adhesion is mediated by PS RBC and endothelial PS receptor. This phenomenon may be one of the factors responsible for CRVO.

Hemodilution therapy using automated erythrocytapheresis in central retinal vein occlusion: results of a multicenter randomized controlled study

BACKGROUND

Central retinal vein occlusion (CRVO) leads to poor visual outcome in most eyes. Abnormal hemorheology was suspected to play a major role in its pathogenesis. CRVO treatment is still a matter of debate but several studies have pointed out the efficacy of isovolumic hemodilution. The aim of this study was to assess the feasibility and efficacy of hemodilution using automated erythrocytapheresis in recent-onset CRVO.

METHODS

In this prospective randomized controlled multicenter study, 61 consecutive CRVO patients were enrolled when they met the following criteria: CRVO lasting for 3 weeks or less, visual acuity ranging from 20/200 to 20/32, age between 18 and 85 years, no diabetes, no uncontrolled systemic hypertension, no antiplatelet or anticoagulant therapy, hematocrit higher than 38%, and signed informed consent. Patients were randomly assigned to the hemodilution group (n = 31) or to the control group (n = 30). Hemodilution therapy consisted of one session of erythrocytapheresis on outpatient basis, followed by additional session(s) for 6 weeks if needed. Target hematocrit was 35%. Follow-up was 12 months.

RESULTS

No statistical differences in age, associated risk factors, or CRVO characteristics were observed at baseline between both groups. Mean visual acuity was equivalent to 20/80 in the hemodilution group and to 20/63 in the control group (non-significant difference). In the treated group, mean number of hemodilution sessions was 3.3 (range, 1 to 6), and no major side-effects occurred. At the 12-month follow-up visit, 64.5% of the hemodilution group had visual acuity of 20/40 or better compared to 40% of the control group (p = .048). Visual change was a gain of 1.7 ETDRS line in the hemodilution group versus a loss of 2.3 lines in the control group (p = .007). There was less conversion into an ischemic form in the hemodilution group (11%) than in the control group (50%, p = .004). Mean final retinal thickness was 289 μm in the hemodilution group versus 401 μm in the control group (p = .068).

CONCLUSIONS

This multicenter controlled randomized study demonstrated that automated erythrocytapheresis is a safe and effective tool for performing hemodilution and confirmed that hemodilution therapy can improve the final prognosis of CRVO when applied in the early phase of the disease.

Effect of oral pentoxifylline on cystoid macular edema associated with central retinal vein occlusion

PURPOSE

To determine whether oral pentoxifylline, a xanthine-derived hemorheologic agent, decreases cystoid macular edema (CME) and improves visual acuity in eyes with a perfused central retinal vein occlusion (CRVO).

METHODS

Retrospective chart review of consecutive patients on pentoxifylline (400 mg po TID) for CRVO was performed. Inclusion criteria included CME, pentoxifylline use for at least 1 month, and a follow-up period of at least 4 months. Exclusion criteria included nonperfused or indeterminate CRVO, the presence of neovascularization, and previous or concurrent laser therapy or any other treatment for CRVO. Statistical analysis of collected data was performed.

RESULTS

Eleven patients were identified. All patients had a perfused CRVO. The mean best-corrected Early Treatment Diabetic Retinopathy Study visual acuity was 60 letters (Snellen equivalent 20/128) before the initiation of oral pentoxifylline. The mean time from onset of CRVO to start of pentoxifylline therapy was 5 months (range, 1-12 months). The mean duration of pentoxifylline use was 5.3 months (range, 2.5-10.2 months). The mean follow-up period was 8 months (range, 2.7-16.5 months). Cystoid macular edema had improved in 64% (7/11) of eyes at last follow-up as measured by biomicroscopy and optical coherence tomography. The visual acuity was not significantly changed at 62 letters (20/128 +2) (Student t-test, P = 0.7) at last follow-up. There were no significant side effects from pentoxifylline. One patient had mild gastrointestinal disturbance.

CONCLUSION

Pentoxifylline has a favorable adverse effect profile, and can reduce CME in eyes with CRVO. Visual acuity does not appear to change significantly. A larger, randomized, multiarmed clinical trial evaluating the effects of pentoxifylline as an adjunctive treatment modality may be of benefit since even a small positive effect in altering the natural history of CME related to CRVO may be of value for these patients.

Retinal Vein Thrombosis as the Presenting Symptom of Essential Thrombocythemia

Visual loss resulting from retinal vascular disorders can be the presenting sign of serious systemic disease. Associations between retinal vein thrombosis and other systemic disorders have been well documented, but a comprehensive literature search failed to reveal any report of essential thrombocythemia as a cause of central retinal vein thrombosis. We describe the first young female patient with symptomatic visual loss due to central retinal vein thrombosis as her presenting symptom of essential thrombocythemia.

Pathogenetic aspects of the glaucomatous optic neuropathy: fluorescein angiographic findings in patients with primary open angle glaucoma

PURPOSE

To identify and quantify the role of retinal circulation, capillary leakage and/or nonperfusion of the optic nerve head in digital fluorescein angiography in normal subjects and patients with open angle glaucoma.

METHODS

Eighteen patients with primary open angle glaucoma (POAG) and 18 healthy age matched subjects were included. Fluorescein angiograms were performed using the scanning laser ophthalmoscope. The arteriovenous passage time (AVP) was assessed by dye dilution technique and describes the shortest passage through a retinal vascular segment. Optic nerve head nonperfusion was marked manually in early angiographic images and is given as percentage of the optic disk area. The fluorescence of the optic nerve head (as measure of the disruption of the blood-brain barrier) and the surrounding retina (ratio of leakage) was measured using digital imaging analysis in the late phases of the angiogram (9-10min).

RESULTS

The AVP time was significantly prolonged ( P=0.001) in patients with open angle glaucoma (AVP 2.29+/-0.32 s) compared to healthy subjects (AVP 1.37+/-0.42 s). The mean percentage of the optic nerve head nonperfusion was 16%. The ratio of optic nerve head fluorescence compared to retinal reference loci was significantly increased (P = 0.02) in patients with glaucoma (1.32+/-0.25) compared with normal subjects (1.32+/-0.19).

CONCLUSIONS

Fluorescein angiography revealed altered retinal perfusion along with optic nerve head nonperfusion and increased vascular leakage in open angle glaucoma patients. These factors appear to influence each other, with ultrastructural changes of the lamina cribrosa accompanying changes in the vasculature and nerve fibers. Longitudinal and interventive studies should help better elucidate the relationship between circulatory and neural loss, adding vasoprotective therapeutic approaches to interfere with the glaucomatous neurodegenerative chain of events.

Central retinal vein occlusion risk profile: a case-control study

PURPOSE

To identify risk factors for central retinal vein occlusion (CRVO).

METHODS

This clinic-based case-control study included 408 patients with CRVO aged 21 years and older and 566 controls who were seen between January 1, 1990, and December 31, 2001. Multivariate logistic regression analysis was used to adjust for various factors and test potential interactions between the different variables.

RESULTS

An increased risk of CRVO was found in persons with systemic hypertension, but odds ratios were greater for older patients. Risk of CRVO increases with age and also in association with hypercoagulability. Diabetes mellitus, kidney disease, and glaucoma were associated with increased risk for CRVO. A significantly greater prevalence of higher erythrocyte sedimentation rate was present in young adults compared with older patients.

CONCLUSIONS

The results suggest a relationship between CRVO and certain risk factors (systemic hypertension, diabetes mellitus, kidney disease, glaucoma, older age) and support the possibility of an association between CRVO and urban location. The findings also support the potential value of medical treatment of underlying medical conditions in preventing occurrence of CRVO.

Cardiovascular and thrombophilic risk factors for central retinal vein occlusion

Retinal vein occlusion (RVO) is a relatively common disease that is often associated with a variety of systemic disorders including arterial hypertension, diabetes mellitus, dyslipidemia, and systemic vasculitis. There are various types of RVO, categorized on the basis of the site of occlusion and on the type of consequent vascular damage. Central retinal vein occlusion (CRVO) is the most frequently occurring and clinically relevant type of RVO. In addition to the well-known classical risk factors, new hemostasis-related ones have been investigated in patients affected by CRVO. The data concerning a number of parameters remain contradictory; yet, high levels of type 1 plasminogen activator inhibitor (PAI-1) and hyperhomocysteinemia appear to play a significant role in the pathogenesis of this disease. Although based on a limited number of studies, this new knowledge could eventually provide important indications regarding prognosis and therapeutic strategies.

Capillary density and retinal diameter measurements and their impact on altered retinal circulation in glaucoma: a digital fluorescein angiographic study

AIM

Normal pressure glaucoma (NPG) patients exhibit prolonged retinal arteriovenous passage times in fluorescein angiography and colour Doppler imaging suggests increased resistance downstream from the central retinal and posterior ciliary arteries. The aim of the study was to elucidate the morphological source of decreased perfusion and increased resistance of the ocular circulation in NPG.

METHODS

Retinal arteriovenous passage time (AVP) and peripapillary arterial and venous diameters were measured in digital scanning laser fluorescein angiograms. For estimation of retinal capillary density the area of the foveal avascular zone (FAZ) and the perifoveal intercapillary area (PIA) was quantified. 36 patients with NPG (mean age 57 (SD 13) years) and 21 healthy subjects (mean age 51 (13) years) were enrolled in the comparative study.

RESULTS

In NPG patients the AVP (2.55 (1.1) seconds) was significantly prolonged (p<0.001) when compared with healthy subject data (AVP: 1.70 (0.39) seconds). No differences for arterial or venous diameter, FAZ, and PIA were observed in NPG patients compared with healthy subjects. FAZ, PIA, arterial and venous diameter were not correlated with visual field indices (except venous diameter with PSD, r=0.35 (p<0.05)) or cup to disc ratios. AVP was significantly correlated (p<0.05) with the size of the optic nerve head (r=-0.28), visual field indices (MD: r=-0.3; PSD: r=0.3; CPSD: r=0.3), and contrast sensitivity (r=-0.34).

CONCLUSION

AVP times are significantly prolonged in NPG. The slowing of the retinal transit does not result from capillary dropout, or changes of peripapillary arterial or venous diameters with increased vascular resistance.

[Extra-ocular etiologic factors in retinal vein occlusion. Retrospective study of 24 patients]

PURPOSE

Retinal vein occlusion has several causes. Cardiovascular risk factors, particularly systemic hypertension; as well as thrombophilia appear to be involved in the development of retinal vein occlusion.

METHODS

In a retrospective study we analyzed these factors in 24 patients, admitted for retinal vein occlusion and isovolaemic hemodilution in an internal medicine unit.

RESULTS

In patients over 50 years of age, cardiovascular risk factors predominate; while in patients under 50, one patient out of two has biological features indicating a risk for thrombosis.

CONCLUSION

Serological abnormalities could be involved in the physiopathology of retinal vein occlusion in young patients.

Familial thrombophilia and retinal vein occlusion

PURPOSE

To perform a pilot study on the prevalence of familial thrombophilia in all cases of retinal vein occlusion with no known risk factors.

METHODS

Over the 1 year study period 71 patients presented with a new diagnosis of retinal vein occlusion (age 28-90 years). Fifty-five (77%) were excluded because of local predisposing factors. The remaining 16 (23%) had a full risk factor history taken and blood investigations of rheological factors and thrombophilia including tests for the factor V Leiden mutation, prothrombin G20210A allele and hyper-homocystinemia.

RESULTS

Of those with no local predisposing factors, 3 patients had antiphospholipid antibodies, 3 had raised fibrinogen levels, 4 had hyper-homocystinemia and 1 was heterozygous for the Leiden mutation. Other lifestyle risk factors such as obesity, smoking and a positive family history of venous thrombosis were not uncommon. No patient had the prothrombin G20210A variant.

CONCLUSIONS

It seems likely that several risk factors, both genetic and acquired, need to be present for thrombosis to occur. In investigating a new patient with a retinal vein occlusion one should test for hypertension, glaucoma and diabetes mellitus. Estimation of plasma viscosity and a full blood count are cheap investigations which may reveal neoplasia or vasculitis, and lipid levels should be estimated. In a young patient or one with an unexpected vein occlusion and a personal or family history of thrombosis, a hypercoagulable state may rarely be identified. This additional testing should include testing for antiphospholipid antibodies and a full thrombophilia screen including the factor V Leiden mutation, homocysteine and the prothrombin variant as part of a clinical trial. Until the role of these markers in thrombosis is better defined in relation to causation of retinal vein occlusion and treatment has been shown to improve outcome, we can not recommend them for routine testing. If a hereditary defect is found, referral should be made to a hematologist and consideration given to anticoagulation and screening of family members to prevent further thrombotic episodes. Retinal vein occlusions are multifactorial in origin except in rare cases.

Coagulation abnormalities and their neuro-ophthalmologic manifestations

Congenital and acquired hypercoagulable states arise from an imbalance between procoagulant and anticoagulant forces. Although these conditions are present throughout the vascular tree, they typically give rise to local thrombotic lesions in discrete segments of the veins or arteries; this suggests that focal defects in the vascular wall or blood flow must be associated with a hypercoagulable state to produce thrombosis. Numerous new factors associated with hypercoagulability have been described in the past few years. Congenital and acquired hypercoagulable states are reviewed here, with an emphasis on recent data on focal thrombosis involving the eye and central nervous system.

Hypercoagulable states in patients with retinal venous occlusion

BACKGROUND AND PURPOSE

The pathogenesis of thrombus formation in the retinal vein resulting in retinal vein occlusion is not well understood. This study was carried out to ascertain the role of hypercoagulable states in patients with retinal vein occlusion.

METHODS

Fifty seven consecutive patients with acute retinal vein occlusion (mean age 48 +/- 11.5 years) were investigated for possible hypercoagulable states. Levels of antithrombin III (AT III), protein C (PC), Protein S (PS), factor XII, and fibrinogen as well as the presence of antiphospholipid antibodies (APAs) were investigated. The APAs and fibrinogen results obtained in these patients were compared to those of healthy controls.

RESULTS

We detected APAs in 15 out of 57 patients compared to 3 out of 74 controls (p = 0.0002). Fibrinogen levels were significantly higher in patients compared with the controls (p < 0.001). Deficiencies in the naturally occurring anticoagulant proteins including AT III (4 out of 54 patients tested), PC (8 out of 42 patients tested), and PS (12 out of 56 patients tested) were detected. Seven patients out of 32 patients tested had reduced levels of factor XII. Subgroup analysis of the thrombophilic differences between patients who aged 45 years or less and older patients and patients with major trunk vein occlusion and patients with branch vein occlusion revealed no significant differences.

CONCLUSION

Hypercoagulable states are common in patients with retinal vein occlusion and may contribute to the etiology of the disease.

Retinal vein occlusion in Armenia

PURPOSE

To determine the demographic characteristics, associated ophthalmic and systemic conditions of retinal vein occlusion (RVO) and associations of central retinal vein occlusion among Armenian patients.

METHODS

A retrospective study of 460 patients aged 30 years and older with a clinical diagnosis of RVO who were seen in the five-year period between January 1, 1993, and December 31, 1997 at the Eye Hospital.

RESULTS

Signs of central RVO were found in 297 eyes (64.5%), branch RVO in 163 eyes (35.5%). Among the 460 patients occlusion was hemispheric in 4 eyes (2.4%), hemicentral in 5 eyes (3%). CRVO was more common among the younger patients (odds ratio [OR] = 2.42, 95% confidence interval [CI]: 1.06-5.65). Hypercoagulability was noted in the majority of RVO cases. Glaucoma was an associated condition (12.6%). Systemic hypertension was the most frequent association. In CRVO a significant association was found with hypertension (OR = 1.89, 95% CI: 1.23-2.70).

CONCLUSIONS

Our results suggest RVO is associated with glaucoma and hypertension. RVO was more closely associated with hypertension than BRVO. There were no differences in the distribution for the site of occlusion with regard to sex in patients with CRVO and BRVO. No seasonal pattern was found in the onset of any type of RVO. Hypercoagulability may be a contributing factor in the pathogenesis. The findings reinforce recommendations to carefully evaluate patients with RVO for open-angle glaucoma, and to diagnose and treat systemic hypertension.

Central retinal vein occlusion: review of management

Central retinal vein occlusion is usually a disease of the elderly and is often associated with systemic vascular disease, e.g., hypertension, diabetes mellitus, arteriosclerotic vascular disease. Younger patients, especially those less than 45 years of age, with retinal vein occlusion should be evaluated carefully for the possibility of an underlying thrombotic tendency. The authors describe the ocular manifestations, pathogenesis, associated conditions, patient evaluation, and treatment of patients with central retinal vein occlusion.

Abnormalities in haemorheological factors and lipoprotein (a) in retinal vascular occlusion: implications for increased vascular risk

BACKGROUND

The pathogenesis of retinal vascular occlusion (RVO), which includes patients with retinal vein or artery occlusions, may be associated with abnormalities of rheology and coagulation. These abnormalities have previously been linked with an increased risk of cardiovascular disease and stroke.

AIM, PATIENTS AND METHODS

To investigate changes in haemorheological factors (plasma viscosity, haematocrit, haemoglobin, white cell count (WCC), plasma fibrinogen (CLAUSS), soluble adhesion molecule P-selectin (associated with platelet activity and atherosclerosis; ELISA), von Willebrand factor (vWf, an index of endothelial dysfunction; ELISA), fibrin D-dimer (ELISA), lipoprotein(a) (Lp(a), immunoturbidometric assay) and serum lipids, we conducted a cross-sectional case-controlled study of 49 patients (37 men; mean age 66.9 years, SD 12.1 years) with RVO; 34 patients had retinal vein occlusion, whilst 15 had retinal artery occlusion. Their results were compared with those in 36 healthy controls (21 men; mean age 63.7 years, SD 14.8 years).

RESULTS

Patients with retinal vein occlusion and retinal artery occlusion had higher systolic and diastolic blood pressures compared with controls (both p < 0.0001). These patients also had significantly elevated levels of plasma viscosity, haematocrit, haemoglobin, plasma fibrinogen, PAI, fibrin D-dimer and serum Lp(a) compared with controls. Apart from a reduction in blood pressure, there were no significant differences in the indices measured in patients with retinal vein occlusion when levels measured during their first and second visits were compared. In patients with retinal artery occlusion mean plasma PAI levels were significantly lower at visit 2 compared with visit 1. Plasma viscosity was significantly correlated with fibrinogen (r = 0.63, p < 0.001), systolic blood pressure (r = 0.33, p = 0.03) and cholesterol (r = 0.32, p = 0.04), while P-selectin was correlated with Lp(a) levels (r = 0.38, p = 0.03).

CONCLUSION

This study suggests that abnormalities in haemorheological factors, fibrinogen and Lp(a) are present in patients with retinal vein occlusion and retinal artery occlusion. These abnormalities appear to persist even at follow-up examination 4-6 weeks later. Abnormalities in haemorheological factors, fibrinogen and Lp(a) may have a role in the pathogenesis of retinal vein occlusion and retinal artery occlusion, perhaps acting synergistically with clinical risk factors such as blood pressure. In addition, as haemorheological factors, fibrinogen and Lp(a) are associated with vascular disease, these findings in patients with RVO may potentially contribute to an increased risk of cardiovascular disease and stroke.