Parnaparin versus aspirin in the treatment of retinal vein occlusion. A randomized, double blind, controlled study

Antithrombotic treatment for retinal vein occlusion: a systematic review and meta-analysis

BACKGROUND

Retinal vein occlusion (RVO) represents a common thrombotic disorder.

OBJECTIVES

In this meta-analysis, we evaluated the efficacy and safety of anticoagulant and antiplatelet therapy in RVO.

METHODS

MEDLINE and EMBASE were searched up to December 2021 for observational studies and randomized controlled trials including patients with RVO. Efficacy outcomes were best-corrected visual acuity improvement, recurrent RVO, fluorescein angiography improvement, cardiovascular events, and safety outcomes were major bleeding and intraocular bleeding.

RESULTS

A total of 1422 patients (15 studies) were included. Antiplatelet therapy was administered to 477 patients (13 studies), anticoagulant therapy to 312 patients (12 studies), and 609 (7 studies) patients received no antithrombotic treatment. The treatment duration ranged between 0.5 and 3 months. The median follow-up duration was 12 months. Best-corrected visual acuity improvement was reported in 58% of the patients (95% confidence interval [CI], 45%-69%) overall, 64% (95% CI, 58%-71%) in those on anticoagulant therapy, and 33% (95% CI, 21%-47%) in those on antiplatelet therapy. The rates of recurrent RVO was 11% (95% CI, 7%-17%), 7% (95% CI, 2%-19%), and 15% (95% CI, 8%-28%), respectively. The rate of recurrent RVO in untreated patients was 9% (95% CI, 6%-14%). The rate of major bleeding was 5% (95% CI, 3%-9%) overall, 4% (95% CI, 2%-9%) in those on anticoagulant therapy, and 7% (95% CI, 2%-23%) in those on antiplatelet therapy.

CONCLUSION

Anticoagulant therapy was associated with higher visual acuity improvement and fewer recurrent RVO events than antiplatelet therapy, at the cost of an acceptable proportion of bleeding complications.

Clinical Features of Central Retinal Vein Occlusion in Young Patients

Retinal vein occlusion (RVO) is the second most common retinal vascular disease. Central RVO (CRVO), in which obstruction occurs posterior to the lamina cribrosa due to various causes, manifests with extensive venous tortuosity, dilatation of blood vessels in the four quadrants, and retinal hemorrhage. The presence of macular edema decreases visual acuity in patients with CRVO, especially in elderly patients with hypertension, hyperlipidemia, and diabetes. In the last decade, treatment modalities for CRVO have improved, with anti-vascular endothelial growth factor agents being widely used as treatment. However, there are cases of refractory or recurrent macular edema. Moreover, CRVO also occurs in young patients. This article reviews previous studies and case reports and summarizes the differences in etiological factors, clinical manifestations, treatment, and prognosis between young and elderly patients. Due to the low incidence of CRVO in young patients, clinical data from these age groups are limited. Hence, further studies are warranted to explore the differences between age groups to improve individualization of treatment of young patients.

Vitamin B12 levels in patients with retinal vein occlusion and their relation with clinical outcome: a retrospective study

Retinal vein occlusion (RVO) is the second most common retinal vascular disorder, after diabetic retinopathy. Most patients suffering RVO develop some degree of visual loss consequent to retinal complications such as edema and microhemorrhages. Even if some risk factors for RVO have been identified, the clinical outcome of RVO remains highly unpredictable because studies investigating potential prognostic markers for visual improvement are lacking. Cyanocobalamin belongs to the group of B vitamins and plays a role in homocysteine metabolism; however, cyanocobalamin deficiency associates with an increase of some toxic bioproducts involved in endothelial injury and platelet activation independent of homocysteine levels. We retrospectively evaluated the levels of vitamin B12 at diagnosis in 203 patients with RVO, and in a parallel cohort of 120 age- and sex-matched patients without RVO from an internal medicine ward, and correlated them with visual outcome at follow-up (median time 150 days, IQR 30-210). In patients with RVO, vitamin B12 levels at diagnosis were significantly lower than in controls and independently predicted worse clinical outcome at multivariate analysis (OR 3.2; CIs 1.2-8.2; p = 0.015). Our data suggest the opportunity to prospectively evaluate the effect on visual outcome of cyanocobalamin supplementation in RVO patients.

Central Retinal Vein Occlusion: The Effect of Antiplatelet and Anticoagulant Agents

Purpose:

This work evaluates the effect of antiplatelet and anticoagulant agents on clinical outcomes, optical coherence tomography (OCT) parameters, and macular ischemia in eyes with central retinal vein occlusion (CRVO).

Methods:

A retrospective longitudinal cohort study was performed to evaluate patients with CRVO. Demographics, OCT parameters before and after treatment, macular ischemia on fluorescein angiography, and clinical outcomes including the number of injections received were analyzed.

Results:

A total of 365 patients with CRVO were identified. The average follow-up was 36 months. Antiplatelet or anticoagulant agent use was not associated with a significant difference in visual acuity (VA), prevalence of macular edema, or central subfield thickness on OCT at presentation or final visit. The use of 81-mg aspirin alone was associated with an increased prevalence of foveal hemorrhage at presentation. Patients who were taking an antiplatelet agent, an anticoagulation agent, or both and had an ischemic CRVO with logMAR VA of less than 1.0 experienced improved VA at the final study visit. Patients given antiplatelet or anticoagulant agents had a similar incidence of neovascular sequelae compared with patients not administered these agents.

Conclusions:

In eyes with CRVO, the use of antiplatelet or anticoagulant agents at CRVO onset was not associated with significantly different functional outcomes, except in ischemic CRVO eyes with VA of less than 20/200. The use of 81-mg aspirin was associated with foveal hemorrhage at CRVO presentation. Otherwise, the use of any antiplatelet agent or anticoagulation was not associated with any CRVO structural outcomes.

Effects of Antithrombotic Agents on Ophthalmological Outcomes, Cardiovascular Risk, and Mortality in Hypertensive Patients with Retinal Vein Occlusion: An Exploratory Retrospective Study

Background and objectives: Because few data are available, the aim of this study is to analyze the effects of antithrombotic agents (ATAs) on visual function and long-term risk of cardiovascular events and mortality in hypertensive patients with retinal vein occlusion (RVO). Materials and methods: Hypertensive patients with RVO were consecutively selected from 2008 to 2012 and followed for a median of 8.7 years. Ophthalmologists evaluated and treated RVO complications, and best-corrected visual acuity (BCVA) was checked at each visit during the first one year of follow-up. Survival analysis was conducted on the rate of the composite endpoint of all-cause deaths or non-fatal cardiovascular events. Results: Retrospectively, we collected data from 80 patients (age 68 ± 12 years, 39 males). Central and branch RVO was present in 41 and 39 patients, respectively, and 56 patients started ATAs (50 antiplatelet drugs, 6 warfarin, and 2 low-molecular weight heparin). Average BCVA of the cohort did not change significantly during one-year of follow-up. The only predictor of BCVA was the baseline BCVA value. There was a reduction in proportion and severity of macular edema and an increase in the cumulative proportion of retinal vein patency reestablishment during the follow-up, independent of treatment. ATAs had no effects on one-year BCVA, intraocular complications, or the composite endpoint rate. Conclusions: In this exploratory study, ATAs had no effect on BCVA during the first one year of follow-up and on the composite endpoint during the long-term follow-up. Further prospective studies need to be conducted with an accurate standardization of the intraocular and antithrombotic treatment to define the positive or negative role of ATAs in hypertensive patients with RVO.

Role of Increased Lipoprotein (a) in Retinal Vein Occlusion: A Systematic Review and Meta-analysis

Background  Increased lipoprotein (a) [Lp(a)] has been associated with enhanced risk of cardiovascular events and more recently with venous thromboembolism. However, there is inconclusive data on the association between enhanced Lp(a) and retinal vein occlusion (RVO). We aimed to assess the role of Lp(a) in RVO.

Methods  We performed a systematic review and meta-analysis of the studies addressing the role of Lp(a) in RVO. A systematic literature search was performed to identify all published papers reporting Lp(a) levels. Main outcome measures consisted of Lp(a) levels in patients with (cases) or without (controls) RVO.

Results  We included 13 studies for a total of 1,040 cases and 16,648 controls. Lp(a) levels above normal limits were associated with RVO (OR 2.38, 95% CI 1.7–3.34) and patients with RVO had higher Lp(a) levels than controls (weighted mean difference: 13.4 mg/dL, 95% CI 8.2–18.6).

Conclusion  Increased Lp(a) levels associate with RVO and should be included among diagnostic and prognostic indexes for this unusual-site vein thrombosis. Therapeutic interventions aimed to lower Lp(a) should be tested in RVO patients.

Treatment of retinal vein thrombosis: what about anticoagulants?

Retinal vein occlusion is an important cause of vision loss. The current treatment options are mainly directed to the prevention of neovascular complications and few studies have addressed to potential use of anticoagulant agents and other interventions targeting the coagulation system. Herein we review the general aspects of this condition focusing on the potential benefits of anticoagulant treatment.

Treatment of unusual thrombotic manifestations

Venous thrombosis rarely occurs at unusual sites such as cerebral, splanchnic, upper-extremity, renal, ovarian, or retinal veins. Clinical features, symptoms, and risk factors of rare thrombotic manifestations are heterogeneous and in large part differ from those typical of the commonest manifestations of venous thrombosis at the lower extremities. The therapeutic approach also varies widely according to the affected site, whether cerebral, abdominal, or extraabdominal. To date, anticoagulant therapy for thrombosis at unusual sites is generally accepted, but the optimal therapeutic approach remains challenging. This review is focused on the treatment of unusual thrombotic manifestations as reported in the most recent guidelines and according to the updated scientific literature.

New Developments in the Classification, Pathogenesis, Risk Factors, Natural History, and Treatment of Branch Retinal Vein Occlusion

For years, branch retinal vein occlusion is still a controversial disease in many aspects. An increasing amount of data is available regarding classification, pathogenesis, risk factors, natural history, and therapy of branch retinal vein occlusion. Some of the conclusions may even change our impression of branch retinal vein occlusion. It will be beneficial for our doctors to get a deeper understanding of this disease and improve the treatment skills. The aims of this review is to collect the information above and report new ideas especially from the past a few years.

Retinal vein thrombosis: The Internist's role in the etiologic and therapeutic management

Retinal vein occlusion is a common and important cause of vision loss. In general, knowledge about this condition is scant within an internist's practice but the condition is relevant because of its association with other chronic ailments. A diagnosis of RVO should prompt the investigation of conditions needing chronic management in these patients. In this review we summarize the clinical presentation of RVO, its classification, associated risk factors, and treatment focused in the internist's scope of practice.

Guidance for the management of venous thrombosis in unusual sites

Venous thromboembolism (VTE) is a serious and often fatal medical condition with an increasing incidence. The treatment of VTE is undergoing tremendous changes with the introduction of the new direct oral anticoagulants and clinicians need to understand new treatment paradigms. This manuscript, initiated by the Anticoagulation Forum, provides clinical guidance based on existing guidelines and consensus expert opinion where guidelines are lacking. In this chapter, we address the management of patients presenting with venous thrombosis in unusual sites, such as cerebral vein thrombosis, splanchnic vein thrombosis, and retinal vein occlusion. These events are less common than venous thrombosis of the lower limbs or pulmonary embolism, but are often more challenging, both for the severity of clinical presentations and outcomes and for the substantial lack of adequate evidence from clinical trials. Based on the available data, we suggest anticoagulant treatment for all patients with cerebral vein thrombosis and splanchnic vein thrombosis. However, in both groups a non-negligible proportion of patients may present with concomitant bleeding at the time of diagnosis. This should not contraindicate immediate anticoagulation in patients with cerebral vein thrombosis, whereas for patients with splanchnic vein thrombosis anticoagulant treatment should be considered only after the bleeding source has been successfully treated and after a careful assessment of the risk of recurrence. Finally, there is no sufficient evidence to support the routine use of antithrombotic drugs in patients with retinal vein occlusion. Future studies need to assess the safety and efficacy of the direct oral anticoagulants in these settings.

Optimal Treatment of Retinal Vein Occlusion: Canadian Expert Consensus

Background: The availability of new therapeutic approaches, particularly intravitreal anti-vascular endothelial growth factor (anti-VEGF) therapies, has prompted significant changes to the established treatment paradigms for retinal vein occlusion (RVO). Better visual outcomes and significantly lower rates of adverse events have been noted in multiple large randomized clinical trials and have led to a new standard of care for this sight-threatening condition. Objective: To develop an expert consensus for the management of RVO and associated complications in the context of recent clinical evidence. Methods: The development of a Canadian expert consensus for optimal treatment began with a review of clinical evidence, daily practice, and existing treatment guidelines and algorithms. The expert clinicians (11 Canadian retina specialists) met on February 1, 2014, in Toronto to discuss their findings and to propose strategies for consensus. Results: The result of this expert panel is a consensus proposal for Canadian ophthalmologists and retina specialists treating patients presenting with RVO. Treatment algorithms specific to branch and central RVO (BRVO and CRVO) were also developed. Conclusions: The consensus provides guidelines to aid clinicians in managing RVO and associated complications in their daily practice. In summary, laser remains the therapy of choice when neovascularization secondary to RVO is detected. Adjunctive anti-VEGF could be considered in managing neovascularization secondary to RVO in cases of vitreous hemorrhage. Intravitreal anti-VEGF should be considered for symptomatic visual loss associated with center-involving macular edema on optical coherence tomography. Patients with BRVO and a suboptimal response to anti-VEGF could be treated with grid laser, and those with CRVO and an inadequate response to anti-VEGF may be candidates for intravitreal steroids.

Risk factors associated with retinal vein occlusion

AIMS

Retinal vein occlusion (RVO) is the most frequent retinal vascular disease after diabetic retinopathy in which arterial risk factors are much more relevant than venous factors. The objective was to evaluate the role of risk factors in the development of the first episode of RVO.

SUBJECTS AND METHODS

One hundred patients with RVO [mean age 56 years, 42% females and mean body mass index (BMI) 27.5 kg/m(2)] were recruited consecutively from the outpatient clinic of a tertiary hospital in Valencia (Spain). All subjects underwent clinical assessment including anthropometric and blood pressure measurements and laboratory test including homocysteine, antiphospholipid antibodies (aPLAs) and thrombophilia studies. In half of the subjects, a carotid ultrasonography was performed. Three control populations matched by age, sex and BMI from different population-based studies were used to compare the levels and prevalence of arterial risk factors. One cohort of young patients with venous thromboembolic disease was used to compare the venous risk factors.

RESULTS

Blood pressure levels and the prevalence of hypertension were significantly higher in the RVO population when compared with those for the general populations. There was also a large proportion of undiagnosed hypertension within the RVO group. Moreover, carotid evaluation revealed that a large proportion of patients with RVO had evidence of subclinical organ damage. In addition, homocysteine levels and prevalence of aPLAs were similar to the results obtained in our cohort of venous thromboembolic disease.

CONCLUSIONS

The results indicate that hypertension is the key factor in the development of RVO, and that RVO can be the first manifestation of an undiagnosed hypertension. Furthermore, the majority of these patients had evidence of atherosclerotic disease. Among the venous factors, a thrombophilia study does not seem to be useful and only the prevalence of hyperhomocysteinaemia and aPLAs is higher than in the general population.

Risk Factors and Treatment Strategies in Patients With Retinal Vascular Occlusions

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.

Branch retinal vein occlusion: treatment modalities: an update of the literature

BACKGROUND

Retinal vein occlusion is the second most common retinal vascular disorder after diabetic retinopathy and is considered to be an important cause of visual loss. In this review, our purpose is to update the literature about the treatment alternatives for branch retinal vein occlusion.

METHODS

Eligible papers were identified by a comprehensive literature search of PubMed, using the terms "branch retinal vein occlusion," "therapy," "intervention," "treatment," "vitrectomy," "sheathotomy," "laser," "anti-VEGF," "pegaptanib," "bevacizumab," "ranibizumab," "triamcinolone," "dexamethasone," "corticosteroids," "non-steroids," "diclofenac," "hemodilution," "fibrinolysis," "tPA," and "BRVO." Additional papers were also selected from reference lists of papers identified by the electronic database search.

RESULTS

Treatment modalities were analyzed.

CONCLUSIONS

There are several treatment modalities for branch retinal vein occlusion and specifically for its complications, such as macular edema, vitreous hemorrhage, retinal neovascularization, and retinal detachment, including anti-aggregative therapy and fibrinolysis, isovolemic hemodilution, vitrectomy with or without sheathotomy, peripheral scatter and macular grid retinal laser therapy, non-steroid agents, intravitreal steroids, and intravitreal anti-vascular endothelial growth factors (anti-VEGFs).

Risk factors, antithrombotic treatment and outcome in retinal vein occlusion: an age-related prospective cohort study

OBJECTIVES

Antithrombotic treatment for retinal vein occlusion (RVO) is controversial, although RVO has been surmised as a predictor of a subsequent vascular event. We aimed to evaluate risk factors, the effects of antithrombotic therapy and the occurrence of subsequent vascular events in patients with a first episode of RVO, according to age of RVO onset.

METHODS

In this prospective cohort study, patients with central (CRVO) and branch RVO (BRVO) confirmed by fluorescein angiography were studied; they were divided according to age. Cardiovascular risk factors and thrombophilia were evaluated. Anticoagulants or aspirin were given for at least 3 months. Patients were followed every 6-12 months and vascular events were recorded.

RESULTS

One hundred CRVO and 32 BRVO patients were enrolled. Five of 60 (8.3%) patients <50 yr and 4/72 (5.5%) over 50 yr had a hereditary thrombophilic defect. One or more cardiovascular risk factors were found in 35 (58%) patients of the younger group, and in 66 (91%) of the older group (P < 0.001). Antithrombotic treatment led to both a satisfactory recanalization of occluded veins and visual acuity improvement especially in younger patients. Vascular events occurred in 19 (14%) cases after 4 ± 3.3 yr from RVO, more frequently in older than in younger patients (22% vs. 5%, P = 0.005).

CONCLUSIONS

Distribution of cardiovascular, but not of thrombophilic risk factors seems to be influenced by age in RVO patients. Patients with a first RVO, especially those >50 yr, are likely at risk of a subsequent vascular event.

A hypercoagulable and hypofibrinolytic state is detectable by global methods in patients with retinal vein occlusion

The pathogenesis of retinal vein occlusion (RVO), has not been well understood. Recent data have shown the efficacy of an anticoagulant therapy with LMWHs in the treatment of acute RVO suggesting the presence of a hypercoagulable state in these patients. New global tests for detection of hypercoagulability and hypofibrinolysis have become available and their application might improve the knowledge of the pathophysiology of RVO and, potentially, its treatment. The aim of our study was to evaluate coagulation and fibrinolytic alterations by two global tests in RVO patients: Endogenous Thrombin Potential (ETP) and Clot Lysis Time (CLT), respectively. We studied 81 RVO patients (40 males; median age 61 years) and a control group matched for age and sex. The ETP was measured by functional chromogenic assay and expressed as the time until thrombin burst (LagTime), Time to peak (T(max)), Peak amount of thrombin generation (C(max)) and ETP. CLT was determined by a plasma-based, tissue factor-induced clot lysis assay. C(max), ETP and CLT values were significantly higher in RVO patients than in controls (C(max)p = 0.010; ETP p < 0.001; CLT p < 0.001) and remained significantly associated with the disease at the multivariate analysis adjusted for cardiovascular risk factors. Our results indicate that -beyond the assay of different parameters associated with clotting activation and lysis- global methods might allow us to easily detect the presence of hypercoagulability and hypofibrinolysis in RVO patients. Further studies should assess the possible clinical value of our data in the management of RVO patients.

Unusual site thrombosis

Venous thromboses in unusual sites are rare and heterogenous manifestations of venous thromboembolism (VTE). These uncommon diseases are each characterized by peculiar pathophysiological and clinical features, mainly reflecting the different characteristics of the organs of origin. Moreover, the relative frequency and importance of risk factors associated with their development may be different compared to those of the classical manifestations of VTE, such as deep vein thrombosis of the lower limbs or pulmonary embolism. The need for anticoagulant therapy for unusual site thrombosis (UST) is generally accepted. However, several questions remain unanswered: what is the best therapeutic agent, is it safe, and for how long should it be used? These questions persist mainly due to the low level of available evidence given the rarity of these diseases. The short- and long-term prognoses, and in particular the risk of recurrence and mortality, are quite heterogenous among the different manifestations of UST and even within each of them, depending mainly on the predisposing causes.

Atherosclerotic and thrombophilic risk factors in patients with ischemic central retinal vein occlusion

PURPOSE

To investigate atherosclerotic and thrombophilic risk factors in patients affected by acute ischemic and nonischemic central retinal vein occlusions (CRVOs).

METHODS

One hundred and three patients with acute unilateral CRVO (41 ischemic and 62 nonischemic) were studied. The frequency of traditional cardiovascular risk factors was assessed, and the plasma levels of a variety of thrombophilic markers were measured. Univariate logistic regression was performed to determine risk factors for ischemic CRVO.

RESULTS

Arterial hypertension, hypercholesterolemia, postmethionine hyperhomocysteinemia (HHcy), elevated factor VIII, and reduced folic acid and B6 plasma levels were more frequent in patients with ischemic CRVO than in those with nonischemic CRVO (P = 0.030, P = 0.025, P = 0.011, P < 0.001, P < 0.001, and P = 0.044, respectively). Risk factors for ischemic CRVO were arterial hypertension (odds ratio [OR], 3.22; 95% confidence interval [CI], 1.13-9.21; P = 0.037), hypercholesterolemia (OR, 3.03; 95% CI, 1.06-8.65; P = 0.042), reduced folic acid levels (OR, 6.77; 95% CI, 1.59-28.79; P = 0.011), and elevated FVIII levels (OR, 6.17; 95% CI, 2.56-14.82; P < 0.001). Postmethionine HHcy was associated with low folic acid levels (r = -0.413; P = 0.007; OR, 9.33; 95% CI, 2.06-42.18; P = 0.005).

CONCLUSION

The results of the present study suggest that some atherosclerotic and thrombophilic risk factors may increase the risk of having an ischemic form of CRVO.

Central and hemicentral retinal vein occlusion: role of anti-platelet aggregation agents and anticoagulants

OBJECTIVE

To investigate systematically the role of anti-platelet-aggregating drugs or anticoagulants in central retinal vein occlusion (CRVO) and hemi-CRVO.

DESIGN

Cohort study.

PARTICIPANTS

Six hundred eighty-six consecutive patients with CRVO (567 patients, 585 eyes) and nonischemic hemi-CRVO (119 patients, 122 eyes).

METHODS

At first visit, all patients had a detailed ophthalmic and medical history (including the use of anti-platelet aggregating drugs or anticoagulants), and comprehensive ophthalmic and retinal evaluation. Visual evaluation was carried out by recording visual acuity, using the Snellen visual acuity chart, and visual fields with a Goldmann perimeter. The same ophthalmic evaluation was performed at each follow-up visit. At the initial visit, CRVO and hemi-CRVO were classified as nonischemic and ischemic.

MAIN OUTCOME MEASURES

Visual acuity, visual fields, and severity of retinal hemorrhages.

RESULTS

All 3 types of CRVO, showed a significantly greater severity of retinal hemorrhages among aspirin users than nonusers (P<0.001). Initial visual acuity and visual fields were significantly worse in aspirin users than nonusers in nonischemic CRVO and hemi-CRVO, but did not differ for ischemic CRVO. Among patients with nonischemic CRVO who initially had 20/60 or better visual acuity, there was a significant association of aspirin use with visual acuity deterioration. The odds ratio of visual acuity deterioration, adjusting for age, diabetes, ischemic heart disease, and hypertension, for aspirin users relative to nonusers was 2.24 (95% confidence interval [CI], 1.14-4.41; P = 0.020). Of those whose macular edema resolved, overall cumulative visual acuity outcome also suggested a higher percentage with deterioration among aspirin users, odds ratio for deterioration of 3.62 (95% CI, 0.97-13.54; P = 0.05) for aspirin users relative to nonusers. For the nonischemic CRVO patients with 20/70 or worse visual acuity at the initial visit, after resolution of macular edema, improvement in visual acuity was less likely in the aspirin users than in nonusers (odds ratio, 0.18; 95% CI, 0.04-0.72; P = 0.016).

CONCLUSIONS

Findings of this study indicate that, for patients with CRVO and hemi-CRVO, the use of aspirin, other anti-platelet aggregating agents, or anticoagulants was associated with a worse visual outcome and no apparent benefit.

FINANCIAL DISCLOSURE(S)

The author(s) have no proprietary or commercial interest in any materials discussed in this article.

Retinal vein occlusions: a review for the internist

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.

Low molecular weight heparin for the treatment of retinal vein occlusion: a systematic review and meta-analysis of randomized trials

Retinal vein occlusion is a frequent cause of visual loss for which few effective therapies are available. Anticoagulation with low molecular weight heparin might be of value in its treatment. We conducted a systematic review and meta analysis of randomized trials evaluating the effect of low molecular weight heparin in patients with retinal vein occlusion. Data sources included MEDLINE, EMBASE, HealthSTAR, the Cochrane Library, Lilacs, the Investigative Ophthalmology and Visual Science database and gray literature. Main outcome was the mean difference between the visual acuity measured at baseline and at six months expressed in the logMAR scale. Secondary outcome was a composite of any adverse ocular outcome including: worsening of visual acuity, visual fields or fluorescein angiography, or development of iris neovascularization, any neovascularization or neovascular glaucoma. Subgroup analyses for branch versus central retinal vein occlusion were conducted. We identified 1,084 references of which 3 studies comparing low molecular weight heparin with aspirin (229 evaluable patients) were included. Overall, the pooled mean visual acuity difference was -0.23 logMAR (95% CI -0.38, -0.09; P=0.002) in favor of low molecular weight heparin. Low molecular weight heparin was associated with a 78% risk reduction for developing any adverse ocular outcome (pooled RR 0.22; 95% CI 0.10, 0.46; P<0.001). In subgroup analyses benefits seemed lower in branch retinal vein occlusion. No increased vitreous hemorrhages were observed. In patients with retinal vein occlusion treatment with low molecular weight heparin seems to be associated with improvement in the visual acuity and less adverse ocular outcomes. These benefits might differ in patients with central as opposed to branch retinal vein occlusion. Further studies are required to confirm these findings and clarify its benefits in specific subgroups of patients before definitive recommendations can be made.