Haemorheology in patients with branch retinal vein occlusion with and without risk factors

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.

[Retinal vein occlusion: Therapy of retinal vein occlusion]

Treatment of retinal vein occlusion can be systemic or local. Therapeutic strategies include improved blood supply, treatment of the vision-reducing macular edema by intravitreal injection of inhibitors of vascular endothelial growth factors (VEGF) or corticosteroids and laser photocoagulation for neovascular complications. As long as head-to-head studies comparing steroids and VEGF inhibitors have not been published, none of the available intravitreally injected substances can be given priority. Well-known side effects of intravitreal steroids are cataract formation and ocular hypertension whereas VEGF inhibitors need to be frequently injected. Although therapy for retinal vein occlusion is protracted, initial long-term data indicate that treatment can be terminated in at least half of the patients . Finally, a treatment recommendation according to the current state of data is presented.

Treatments for neuro-ophthalmologic conditions

Neuro-ophthalmology covers disorders that fall between the cracks of Neurology and Ophthalmology. Neurologists see patients with neuro-ophthalmic disorders. Recognition of the diagnosis is difficult enough, but treatment can be challenging. This article reviews several common neuro-ophthalmic disorders, outlining their features and treatments, from retinal vascular disorders to eye movements and blepharospasm.

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.

INTRAVITREAL TRIAMCINOLONE INJECTION FOR TREATMENT OF MACULAR EDEMA SECONDARY TO BRANCH RETINAL VEIN OCCLUSION

PURPOSE

To evaluate the efficacy of intravitreal triamcinolone injection in eyes with macular edema due to branch retinal vein occlusion (BRVO) over a 2-year period.

METHODS

The authors performed a retrospective chart review of 13 eyes of 13 patients (mean age 68 years) who underwent intravitreal injections with 4 mg triamcinolone acetonide for macular edema due to BRVO. Six eyes received a single injection. Repeated injections were performed in one eye twice, four eyes three times, and two eyes four times. Mean follow-up was 13 months (range, 4 to 24). The time between the onset of symptoms and the injection averaged 7.4 months (range, 2 to 24).

RESULTS

Mean postinjection central foveal thickness decreased to 56% of preinjection values (529 mum versus 295 mum, P < 0 .001). Final visual acuity improved in seven eyes (range 2 to 6 Snellen lines), remained the same in four eyes (range 0 to 1 Snellen lines), and worsened in two eyes (range -1 to -4 Snellen lines) compared to baseline. The retinal thickness decreased in all cases; vision improved in most cases. As the number of injections increased cataractous changes increased. Visual acuity improvement was significantly correlated with patient age (P = 0.026). Eight patients developed steroid induced ocular hypertension controlled by topical medication. Cataract extraction was judged to aggravate macular edema in three of the five eyes undergoing surgery, based upon optical coherence tomography or fluorescein angiography. Median best postinjection visual acuity (20/50) was significantly better than that of baseline (20/100) (P = 0.028) as well as last follow-up (20/70) (P = 0.003).

CONCLUSIONS

Intravitreal triamcinolone should be further evaluated as a treatment option for macular edema associated with BRVO.

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.

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.