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 170,190 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Retinal vein occlusion (RVO) is the most common retinal vascular disorder second to diabetic retinopathy. The main risk factors in patients with RVO are hypertension, diabetes, hyperlipidemia, increased blood viscosity and glaucoma. The pathogenesis of RVO has not yet been clarified. In these events platelets could play a very important role. In the present study the platelet response to collagen was deeply investigated. Experiments were carried out on a selected group of RVO patients, which were compared to a group of healthy subjects matched for age, sex, clinical and metabolic characteristics. In resting and activated platelets of both groups of subjects p72syk phosphorylation, phospholipase Cgamma2 phosphorylation, protein kinase C activation, intra-cellular calcium levels and nitric oxide formation were measured. Results show that platelets of patients were more responsive to collagen or ADP than healthy subjects and that the response was significantly different (p < 0.0005) at low concentrations of these agonists. In platelets of patients stimulated with collagen increased phosphorylation of p72syk and phospholipase Cgamma2 was found. Also protein kinase C was more activated in patients. In addition intracellular calcium rise induced by collagen was significantly higher in patients than in healthy subjects. RVO patients showed a lower basal level of nitric oxide both in resting and stimulated platelets compared to healthy subjects. Altogether these results suggest that the platelet hyperaggregability described in patients might be an important factor in the development of RVO contributing to the thrombogenic effects.
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PMID:Platelet activation by collagen is increased in retinal vein occlusion. 1726 50

Retinal vein occlusion (RVO) is the second most common retinal vascular disease after diabetic retinopathy and is a common cause of visual morbidity and blindness in the elderly. A large proportion of patients with RVO have a history of cardiovascular disease, hypertension, diabetes mellitus or open-angle glaucoma. Although RVO is sometimes associated with thrombophilias and coagulation abnormalities, the role of coagulation factors in the development of RVO remains unclear. This review did not find strong evidence to support an extensive work-up for thrombophilic and coagulation diseases for the vast majority of patients. However, when tests for common cardiovascular risk factors for RVO are negative, evaluation for potential coagulation disorders may be indicated, particularly in young patients and in patients with bilateral RVO, a history of previous thromboses or a family history of thrombosis.
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PMID:Retinal vein occlusion: an approach to diagnosis, systemic risk factors and management. 1912 May 47

Retinal vein occlusion (RVO) may affect the central vein (CRVO) or a branch, and occurs in healthy patients or in patients having an arterial risk profile rather than a venous one. Its prevalence is above 1% in subjects older than 40 years. RVO is a cause of painless unilateral vision loss of variable degree. Significant residual visual loss is frequent: it is one of the five main causes of unilateral blindness. The diagnosis is usually easy at fundus examination, which shows multiple hemorrhages, retinal and papillary edema, and venous dilations in the territory of the occluded vein. Its physiopathology remains unknown, the precise cause of flow obstruction being still undetermined. The median age of RVO patients is around 60 years, slightly younger for CRVO where several familial cases have been described. RVO is clearly associated with arterial hypertension and glaucoma, but not with thrombophilia. It is neither associated with cancer risk, nor with classical venous thromboembolism. The risk of ischemic neurovascular event might be doubled in patients aged less than 70 years with RVO. The course of the disease lasts several months, the most frequent complication is macular edema but the most feared is the occurrence of iris or retinal neovascularization (15-20% of CRVO cases). There is no efficient general treatment. A pan-photocoagulation of the retina is performed if a clear risk or early signs of neovascularization are found at follow-up examination. A significant but temporary improvement of vision can be achieved with intravitreal injections of corticosteroids in approximately half the cases of macular edema.
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PMID:[Retinal vein occlusion]. 2039 74

Retinal vein occlusion (RVO) is the most common retinal vascular disease after diabetic retinopathy. Owing to its multifactorial nature, however, management of this condition remains a challenge. Of the two main types of RVO, branch retinal vein occlusion (BRVO) is more prevalent than central retinal vein occlusion (CRVO). Most patients develop the disease at an elderly age, and more than half of them have associated systemic disorders (e.g. hypertension, hyperlipidemia and/or diabetes mellitus). There is no evidence to suggest routine testing for heritable thrombophilias in patients with RVO. The main cause of the visual impairment is macular edema, while neovascularization of the retina and optic disc are the most serious complications leading to vitreous hemorrhage, retinal detachment and neovascular glaucoma. Macular grid laser photocoagulation is an effective treatment for macular edema in patients with BRVO and a visual acuity of 20/40 or less. Other treatment options for reducing the edema are intravitreal steroids, anti-VEGF drugs and vitrectomy. The recently introduced intravitreal application of steroids and anti-VEGF drugs may prove to be a better approach for improving visual acuity. Finally, scatter panretinal laserphotocoagulation can effectively treat neovascularization and its secondary complications.
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PMID:Retinal vein thrombosis: pathogenesis and management. 2195 4

Retinal vein occlusion (RVO) is a 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 clinically relevant type of RVO. In addition to well-known classical risk factors, new thrombophilic factors have been investigated in patients with RVO. Data concerning a number of the parameters remain contradictory; yet, hyperhomocysteinemia and vitamins involved in methionine metabolism appear to play a significant role in the pathogenesis of this disease. Alterations in the fibrinolysis pathway (elevated levels of PAI-1 and Lipoprotein (a)), together with haemorheologic modifications have been recently consistently associated with the disease. Medical treatment includes identification and correction of vascular risk factors. In addition, LMWHs appear to be the best therapeutic approach even if based on a limited number of trials, conducted on a limited number of patients. No data are available on the possible role of antithrombotic strategies in the long-term prevention of recurrent RVO or vascular events.
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PMID:Retinal vein occlusions: a review for the internist. 2159 Apr 40

Retinal vein occlusion can provoke a sudden loss of visual acuity. It is generally unilateral. Risk factors include ageing, arterial hypertension, diabetes and elevated intraocular pressure. Neovascularisation of the retina or iris can occur in patients with macular ischaemia, creating a risk of glaucoma. If macular oedema develops, recovery of visual acuity occurs spontaneously but slowly. Patients must be monitored in order to detect and treat neovascularisation as early as possible. Treatments for macular oedema are disappointing.
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PMID:Retinal vein occlusion. 2175 58

Retinal vein occlusion (RVO) is an obstruction of the retinal venous system, and macular edema (ME) is a complication of RVO that can lead to blindness. The Canadian incidence of visual impairment (VI) due to ME secondary to RVO is unknown. This observational, retrospective study used records from the Southwestern Ontario database to observe the annual incidence, demographics, and comorbidity characteristics of patients with VI due to ME secondary to RVO. From 47,166 patients, 73 with RVO (>40 years old) were identified: 53 with branch retinal vein occlusion (BRVO), 20 with central retinal vein occlusion (CRVO). The annual incidence of VI (visual acuity <20/40 in Snellen equivalent) due to ME secondary to BRVO was (mean (95%CI)) 0.056% (0.011-0.072), and to CRVO was 0.021% (0.008-0.081). Furthermore, a greater proportion of RVO patients had hypertension (68% versus 14%) or dyslipidemia (16% versus 10%), when compared to a healthy control cohort of 76,077 subjects (P < 0.05). This study presents a description of the characteristics of patients with VI due to ME secondary to RVO in a real-world Canadian setting. The results demonstrate that BRVO was more frequent than CRVO, and that RVO in this patient population was associated with several vascular comorbidities.
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PMID:Incidence and Characteristics of Patients with Visual Impairment due to Macular Edema Secondary to Retinal Vein Occlusion in a Representative Canadian Cohort. 2309 91

Retinal vein occlusion (RVO) and retinal artery occlusion (RAO) cause significant visual impairment. The role of thrombophilia and cardiovascular testing is uncertain, and optimal treatment strategies have not been determined. We reviewed medical records of 39 patients with RVO and RAO (23 women and 16 men). Thrombophilia and cardiovascular evaluations were performed and outcomes were reviewed. In all, 24 (61.5%) patients had at least 1 thrombophilia. Elevated factor VIII levels were found in RVO (n = 5) but not in RAO. There are no other significant differences in thrombophilias in RVO compared to those in RAO. Most patients had hypertension(41.2% RAO and 55% RVO) and hyperlipidemia (35.5% RAO and 81.8% RVO). In all, 4 women were using oral contraceptives, 2 were pregnant or postpartum. Follow-up data was available for 28 patients (13 RAO, 15 RVO). Nineteen were treated with aspirin, four with warfarin, and one with low molecular weight heparin. Eight patients reported improvement in vision at time of follow-up (5 RAO, 3 RVO). Multiple risk factors are associated with RVO and RAO, and a complete assessment should include thrombophilia and cardiovascular studies.
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PMID:Risk Factors and Treatment Strategies in Patients With Retinal Vascular Occlusions. 2433 46

Retinal vein occlusion (RVO) is a major cause of vision loss. Of the two main types of RVO, branch retinal vein occlusion (BRVO) is 4 to 6 times more prevalent than central retinal vein occlusion (CRVO). A basic risk factor for RVO is advancing age. Further risk factors include systemic conditions like hypertension, arteriosclerosis, diabetes mellitus, hyperlipidemia, vascular cerebral stroke, blood hyperviscosity, and thrombophilia. A strong risk factor for RVO is the metabolic syndrome (hypertension, diabetes mellitus, and hyperlipidemia). Individuals with end-organ damage caused by diabetes mellitus and hypertension have greatly increased risk for RVO. Socioeconomic status seems to be a risk factor too. American blacks are more often diagnosed with RVO than non-Hispanic whites. Females are, according to some studies, at lower risk than men. The role of thrombophilic risk factors in RVO is still controversial. Congenital thrombophilic diseases like factor V Leiden mutation, hyperhomocysteinemia and anticardiolipin antibodies increase the risk of RVO. Cigarette smoking also increases the risk of RVO as do systemic inflammatory conditions like vasculitis and Behcet disease. Ophthalmic risk factors for RVO are ocular hypertension and glaucoma, higher ocular perfusion pressure, and changes in the retinal arteries.
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PMID:Risk factors for central and branch retinal vein occlusion: a meta-analysis of published clinical data. 2500 43

Retinal vein occlusion (RVO) is the second most common cause of visual loss in the Western World. RVO is usually classified into branch RVO (BRVO) and central RVO (CRVO) according to the anatomical site of the vascular occlusion. The pathogenesis of RVO is not yet fully understood, however an important event is the intraluminal thrombus formation, which is usually secondary to several conditions such as hypertension, hyperlipidemia, diabetes and thrombophilia. The blockage of venous circulation causes an elevation of intraluminal pressure in the capillaries, leading to hemorrhages and leakage of fluid within the retina, increase of interstitial pressure and a consequent reduction of retinal perfusion. Ischemia may develop resulting in secretion of vascular endothelial growth factor (VEGF) that causes further vascular leakage and retinal oedema. VEGF has therefore a leading role in RVO pathogenesis and symptoms. As a consequence use of anti-VEGF agents by intravitreal injections has become very common with the aim to improve the clinical outcomes in these patients. Currently 2 anti-VEGF agents (ranimizumab and aflibercept) have been FDA (Food and Drug Administration) and EMA (European Medicine Agency) approved for the treatment of RVO, while another VEGF inhibitor (bevacizumab) is often used "off-label" in clinical practice. Many treatment regimens have been suggested in the clinical trials with these drugs, as monthly injections or injections when needed, however the ideal regimen has not been defined yet. We conducted a systematic review searching MEDLINE for the following terms: retinal vein occlusion, ranibizumab, bevacizumab, aflibercept, vascular endothelial growth factor, macular oedema. Data were extracted by one author (AG and BE) and checked by a second (BPM, CC). Aim of this article was to review available data for each drug, focusing on their efficacy and safety trying to compare their advantages and limits.
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PMID:Anti-VEGF Therapy for Retinal Vein Occlusions. 2607 57


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