Increased prevalence of factor V Leiden in patients with retinal vein occlusion and under 60 years of age

[Cardiovascular risk factors, haemostasis and antithrombotic treatment in retinal vessel occlusion]

Venous and arterial retinal vascular occlusions are age-related disorders, generally associated with classical cardiovascular risk factors, rather than an isolated ocular disease. As affected patients often also have an increased general risk for other vascular diseases, such as ischemic stroke, an interdisciplinary clarification of cardiovascular risk factors and systemic comorbidities is essential for all patients. Extended hemostaseological investigations may be recommended in those patients who do not match the typical risk profile. Patients at a young age by the time of manifestation, without conventional risk factors as well as patients with an increased risk of developing antiphospholipid syndrome may require a selective clinical investigation including testing for thrombophilic risk factors. Recent studies have clearly demonstrated an association between coagulation and lipid metabolism disorders and the development of both retinal vein and artery occlusions in specific subgroups of patients. Therapeutic approaches to treat retinal vascular occlusions or reduce the long-term risk of recurrences with anticoagulant or antiplatelet drugs have not gained widespread acceptance. However, intravenous thrombolysis may be a valuable treatment option for central retinal artery occlusions within a short time to treatment therapeutic window. For defined disorders of the coagulation system, the administration of antithrombotic drugs to reduce the general vascular risk can be a reasonable approach. This article provides an overview of cardiovascular risk factors, the general vascular risk and the current state of knowledge on ophthalmologically relevant disorders of coagulation and lipid metabolism in patients with venous and arterial retinal vascular occlusions.

Hypercoagulability Testing and Hypercoagulable Disorders in Young Central Retinal Vein Occlusion Patients

PURPOSE

To determine frequency of hypercoagulability testing and hypercoagulable states in patients with central retinal vein occlusion (CRVO) younger than 50 years.

DESIGN

Retrospective cohort study.

PARTICIPANTS

Deidentified patients younger than 50 years with newly diagnosed CRVO from a national insurance claims database.

METHODS

The de-identified Clinformatics Data Mart Database (Optum) containing medical claims from a commercial and Medicare Advantage insurance database was used. All outpatient medical claims (office visits, associated diagnoses, and laboratory testing) and demographic data for each beneficiary during their enrollment were accessible.

MAIN OUTCOME MEASURES

Prevalence of (1) laboratory hypercoagulable workup within 90 days of CRVO diagnosis, (2) new diagnosis of a hypercoagulable state within 1 year of CRVO diagnosis, and (3) diagnosis of hypertension, diabetes mellitus (DM), and hyperlipidemia.

RESULTS

One thousand one hundred eighty-one patients met inclusion criteria. Six hundred seventy-one patients (56.8%) were men, 450 patients (38.1%) had undergone hypercoagulable testing within 90 days, and 136 patients (11.5%) were diagnosed with a hypercoagulable state within 1 year after CRVO diagnosis. This proportion was similar between those patients with DM, hypertension, or hyperlipidemia (10.5% [65/620]) and those without (12.7% [71/561]; P = 0.28). Of the 136 patients diagnosed with a hypercoagulability state, 68.4% (93/136) had undergone testing within 90 days of CRVO diagnosis and 31.6% (43/136) did not. Of those who had not undergone hypercoagulability testing, 5.9% (43/731) were diagnosed with a hypercoagulable state within 1 year compared with 20.7% (93/450) in those who were tested (P < 0.001).

CONCLUSIONS

The prevalence of a hypercoagulable state within 1 year of CRVO diagnosis in patients younger than 50 years was 11.5%, and the prevalence was similar between patients with atherosclerotic risk factors and those without. Rate of testing was only 38.1%. Future research should examine the usefulness of uniform hypercoagulable testing in young CRVO patients.

Methylenetetrahydrofolate reductase polymorphisms as risk factors for retinal venous occlusive disease: A literature review

The role of polymorphisms of methylenetetrahydrofolate reductase (MTHFR) gene in retinal vein occlusion (RVO) is a theme of discussion since the first reports of RVO in patients with MTHFR C677T mutation and without classic acquired risk factors for retinal vascular disease. The association between MTHFR polymorphisms and RVO has been studied over the last 20 years producing conflicting results. This review aims to summarize the literature concerning the role MTHFR polymorphisms as risk factors for RVO.

Genetic correlation between Prothrombin G20210A polymorphism and retinal vein occlusion risk

The aim of this study was to perform an updated meta-analysis to quantitatively investigate the association between G20210A polymorphism of Prothrombin gene and the risk of retinal vein occlusion (RVO), based on the available publications with inconsistent results. We utilized the Stata software to perform the heterogeneity test, association test, Begg's and Egger's tests, and sensitivity analysis. We searched three on-line databases (PubMed, Embase, and WOS) and obtained a total of 422 articles. Based on our selection criteria, 24 case-control studies were finally enrolled in this overall meta-analysis; a subgroup analysis by the factors ethnicity, control source, and RVO type was done. Through the association test of overall meta-analysis, we did not observe a significant difference between RVO cases and controls under the A vs G (allele) (z=1.49, P=0.137), A vs G (carrier) (z=1.42, P =0.155), GA vs GG (z=1.50, P=0.135), and GA+AA vs GG (z=1.50, P=0.135). Furthermore, we observed similar negative results in the association test of subgroup analysis (all P>0.05). Heterogeneity, Begg's, and Egger's tests excluded the presence of high heterogeneity and publication bias. Statistically stable results were observed in the sensitivity analyses. Based on integrated analysis of the current evidence, Prothrombin gene G20210A polymorphism is likely unrelated to the risk of RVO.

Factor V G1691A is associated with an increased risk of retinal vein occlusion: a meta-analysis

We performed a meta-analysis to investigate the association between the Factor V G1691A polymorphism and the risk of retinal vein occlusion (RVO). This analysis included 37 studies involving 2,510 cases and 3,466 controls. Factor V G1691A was associated with an increased risk of RVO in the allele, heterozygote, dominant, and carrier models (PA < 0.001, odds ratios >1), but not the homozygote or recessive models (PA > 0.05). Similar results were observed in a meta-analysis of central retinal vein occlusion (CRVO) and when comparing Caucasian subgroups to population-based controls. These data demonstrate that the G/A genotype of Factor V G1691A is associated with an increased risk of RVO/CRVO in a Caucasian population.

No evidence for thrombophilia in patients with retinal venous occlusion: a systematic GRADE-based review

Retinal venous occlusion represents a common retinal disorder that untreated often leads to severely reduced vision. While general risk factors for vascular disease are known to increase the risk of an event, the role of thrombophilia is controversial. The purpose of this systematic review was to evaluate the evidence for thrombophilia investigation in patients presenting with retinal venous occlusion. Eligible studies were identified by a MESH-based search in PubMed 11-13 of March 2015. The level of evidence was stated according to the guidelines published by the GRADE working group using three levels for quality of evidence: high, moderate and low. A total of 118 studies relating to the study question were identified. After excluding case stories, commentaries, cross-sectional studies and reviews/expert opinions, 28 original papers and two meta-analyses were included in the final qualitative synthesis. The majority of studies were small case-control studies, and only one large cohort study was identified. No randomized controlled trials were retrieved. All the studies were categorized as low quality of evidence. Systematic thrombophilia screening in patients presenting with retinal venous occlusion cannot be recommended.

Association of retinal vein occlusion, homocysteine, and the thrombophilic mutations in a Turkish population: A case-control study

PURPOSE

To compare homocysteine and thrombophilic mutations for the methylenetetrahydrofolate reductase (MTHFR) C677T, factor V Leiden, and prothrombin G20210A between retinal vein occlusion (RVO) and healthy controls in a Turkish population.

MATERIALS AND METHODS

Forty-nine subjects with RVO were compared for homocysteine status and the MTHFR C677T, prothrombin G20210A, and factor V Leiden mutations with those of 68 healthy controls. Then, the groups were subdivided into two subgroups according to age (less than 50 years old, equal to or more than 50 years old) and were further compared.

RESULTS

Mean plasma level of homocysteine was similar, but the frequency of hyperhomocysteinemia was significantly higher in the RVO group when compared with the control group (22.5% and 8.8%, respectively, p = 0.037). The frequency of all thrombophilic mutations was similar between the groups (p > 0.05). The frequency of all thrombophilic mutations and homocysteine levels was also similar between age subgroups (p > 0.05). Only hyperhomocysteinemia was significantly different between subgroups (p = 0.037); the frequency of hyperhomocysteinemia was significantly different in RVO patients less than 50 years old (22.7%) from that in healthy controls less than 50 years old (11.1%). Two RVO patients (4.1%) with bilateral involvement had MTHFR C677T mutation.

CONCLUSIONS

Screening for thrombophilic mutations such as MTHFR C677T, factor V Leiden, and prothrombin G20210A in RVO patients at all ages seems to be unnecessary and not cost-effective. However, thrombophilic disorders should be screened selectively, focusing on young individuals, especially with bilateral involvement, without additional cardiovascular risk factors, or a family history of thrombosis.

Thrombophilic Mutations as Risk Factor for Retinal Vein Occlusion

Background:

Retinal vein occlusion (RVO) is the second most common retinal vein disease and an important cause of blindness and visual morbidity. Many conditions are associated with RVO but the real role of the thrombophilic mutations is still unclear.

Aim:

To evaluate the potential role of thrombophilic mutations in RVO.

Methods:

We have evaluated 113 patients with RVO and compared with 104 volunteer controls. The controls were all healthy blood donors without previous venous thromboembolism episode or arterial thromboembolism episode. All patients were tested for 5 gene variants (here all named as mutations): factor V ( FV) Leiden (G1691A), factor II ( FII; G20210A), 5,1-methylenetetra-hydrofolate reductase ( MTHFR; C677T), plasminogen activator inhibitor 1 ( PAI-1; 4G/5G), and angiotensin-converting enzyme ( ACE; Del/Ins). Statistical analysis were performed by the 2-tailed chi-square test.

Results:

Statistical test showed that TT homozygous patients of the MTHFR C677T mutation ( P = .017) and heterozygous GA patients of the FII G20210A mutation ( P = .018) were significantly higher than that in controls. For FV Leiden, even if the values were higher in patients than in controls, P value was not statistically significant. Conversely, for the ACE (Ins/Del) and PAI-1 (4G/5G) mutations, no difference was observed among genotypes of patients with RVO and control participants.

Conclusions:

In our study, the FII G20210A and the MTHFR C677T mutations resulted significantly higher in patients than in controls; in contrast, thrombophilic mutation of FV, ACE, and PAI-1 genes was not statistically correlated with RVO. In spite of having found an association between some thrombophilic mutations and RVO, more studies with a major number of patients are necessary to determine the final role of these gene variants.

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.

Genetic polymorphisms associated with retinal vein occlusion: a Greek case-control study and meta-analysis

BACKGROUND

The genetic background of retinal vein occlusion (RVO) remains unclear. In the current study, we aimed to replicate polymorphisms related to thrombophilia/hypofibrinolysis in a Greek population and also systematically summarize current evidence available on the topic.

MATERIALS AND METHODS

A total of 48 RVO patients and 53 controls were genotyped for factor V H1299R and V Leiden, β-fibrinogen G455A, PAI-1 4G/5G, ACE I/D, HPA1, prothrombin G20210A, factor XIII Val34Leu, MTHFR A1298C and C677T polymorphisms. We examined the association between RVO and the above polymorphisms under a per-allele genetic model in a Greek unrelated case/control population. Additionally, searching PubMed up to January 2012, we identified existing evidence on these polymorphisms and performed meta-analyses.

RESULTS

A total of three polymorphisms had nominally significant associations with RVO. These associations pertained to ACE D allele (odds ratio, OR, 2.08 [95% CI, 1.12-3.85], p = 0.02); factor XIII 34Leu allele (OR = 0.41 [95% CI, 0.18-0.95], p = 0.037] and MTHFR 677T variant (OR = 2.20 [95% CI 1.10-4.40], p = 0.026). We performed a meta-analysis on the associations between RVO and PAI-1 (n = 5), factor V Leiden (n = 21), MTHFR C677T (n = 19) and prothrombin G20210A (n = 21). We observed nominally significant associations only for PAI-1 (OR = 1.27 [95% CI, 1.02-1.60, p = 0.036]) (I(2) = 44.7%), and factor V Leiden (OR = 1.40 [95% CI, 1.07-1.84, p = 0.015]) (I(2) = 3.6%) using random effects model.

CONCLUSIONS

Our results suggest that there may be an association between increased risk for RVO and ACE I/D, MTHFR C677T, PAI-1 4G/5G and factor V Leiden polymorphisms, whereas the Val34Leu variant may exert a protective effect.

The role of prothrombotic factors in the ocular manifestations of abusive and non-abusive head trauma: a feasibility study

OBJECTIVES

Retinal hemorrhage is a cardinal manifestation of abusive head injury. Thrombophilia is relatively common in the general population and in adults can be associated with retinal hemorrhage. The specificity of retinal hemorrhage for abusive head trauma in the presence of prothrombotic factors, in particular following non-abusive head trauma, has not been investigated. Our objective was to determine whether the hypothesis that prothrombotic factors affect specificity of retinal hemorrhage to AHT can be tested. This may have important ramifications both for diagnosis and expert witness testimony.

METHODS

To investigate the feasibility of studying this issue, we conducted a prospective cohort study of children with abusive and non-abusive head trauma. Thrombophilia screening and ophthalmic examinations were performed.

RESULTS

Six of 30 admitted children were fully enrolled. Enrollment obstacles included caregiver stress, animosity towards allegations of abuse, child protection services involvement, and research phlebotomy coordination. Prevalence of thrombophilia was high in children with retinal hemorrhage and in 1 case the question of hemorrhage adjudicated as abuse was considered in light of a history of a fall.

CONCLUSION

We estimate that to answer the critical question of retinal hemorrhage specificity for abuse in the presence of thrombophilia will require 53 centers for a 1 year study or 18 centers for a 3-year study. We identify potential obstacles and interventions.

[Thrombophilic and systemic risk factors in patients with retinal vein occlusion]

Over the past years there has been a dramatic increase in the number of identifiable causes of thrombophilia. However, as retinal vein occlusions (RVO) have a strong pathogenic correlation with the presence of hypertension or arteriosclerosis and the average age of affected patients is usually within the sixth or seventh decade of life, thrombophilia screening of RVO patients poses a particularly difficult diagnostic challenge. It is clear that to use medical resources appropriately and improve the level of interdisciplinary patient care in RVO, subgroup analysis is required. Just recently, some studies have demonstrated the significant role of coagulation disorders in specific subgroups of RVO patients and have provided recommendations for clinical practice. These results indicate that thrombophilic risk factors are significantly more prevalent among patients equal or less than 45 years of age at the time of RVO or a previous thromboembolic event, among patients with a remarkable family history of thromboembolism prior to the age of 45 years, or among patients without cardiovascular risk factors. According to these data, thrombophilia screening should be considered in these selected subgroups.

Management of macular edema secondary to branch retinal vein occlusion: an evidence-based update

Retinal vein occlusions are common retinal vascular disorders with the potential for significant vision-related morbidity. Retinal vein occlusions are classified as either branch retinal vein occlusion (BRVO), central retinal vein occlusion (CRVO), or hemiretinal vein occlusion (HRVO) based on the specific occlusion site. The most common cause of decreased vision in patients afflicted with BRVO is the accumulation of fluid within the macula (macular edema). The Branch Vein Occlusion Study (BVOS) demonstrated the efficacy of grid laser photocoagulation in the treatment of BRVO-related macular edema. After publication of that report, grid laser became the standard of care for decreased vision due to BRVO-associated macular edema in patients similar to those enrolled in the BVOS. However, several recent major randomized, controlled clinical trials have investigated new therapeutic modalities for the treatment of decreased vision due to macular edema secondary to BRVO. This article aims to provide insight into current evidence-based approaches to management of macular edema secondary to BRVO. A companion article reviews approaches for management of macular edema secondary to CRVO.

[Retrospective case analysis of ophthalmological and systemic risk factors in patients with retinal vascular occlusion]

OBJECTIVE

The aim was to determine systemic risk factors for acute central retinal artery occlusion (CRAO) and central retinal vein occlusion (CRVO) and to evaluate the usefulness of systemic diagnostics in CRAO and CRVO.

METHODS

The study consisted of a retrospective chart review including 80 patients (CRAO 38, CRVO 42). All patients underwent systemic diagnostics including blood pressure measurement, blood cholesterol level, carotid Doppler imaging, transthoracic echocardiography (TTE), intraocular pressure measurement, glaucoma history and presence of thrombophilic factors. A systemic medical history was obtained.

RESULTS

Systemic hypertension was found in 76.3% CRAO and 75.6% CRVO patients. Abnormal cardiac findings were detected in 61% (CRAO) and 22% (CRVO). Abnormal carotid findings were detected in 44.1% for CRAO and 9.5% for CRVO. Pathological thrombophilic factors were found in both groups for approximately 15%.

CONCLUSIONS

TTE and carotid Doppler are important tools in the diagnosis of sources of emboli in patients with CRAO, while for CRVO abnormal findings are revealed by TTE and carotid Doppler less often. Thrombophilia should be ruled out in the absence of common risk factors, especially in younger patients and systemic hypertension should be adequately controlled.

Retinal vein thrombosis: pathogenesis and management

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.

The role of thrombophilia in patients with retinal vein occlusion and no systemic risk factors

OBJECTIVE

The role of thrombophilia in the etiology of retinal vein occlusion (rVO) has not been adequately clarified. The aim of this study was to examine the prevalence of thrombophilia among RVO patients with and without systemic risk factors and among patients younger and older than 50 years.

DESIGN

Prospective case-control study.

PARTICIPANTS

One hundred and twenty one patients with RVO, including 92 with acquired risk factors (hypertension, hyperlipidemia, and diabetes mellitus) and 29 without these factors. The control group included 60 persons matched for age, sex, and risk factors.

METHODS

All participants were screened for Leiden mutation (FV Leiden), hyperprothrombinemia (20210 G/A mutation) and deficiency of protein C, S, and antithrombin.

RESULTS

The prevalence of FV Leiden was significantly higher among RVO patients without risk factors (24.1%) than among controls without risk factors (0%; p = 0.034) and among RVO patients with acquired disorders (4.3%; p = 0.001). No significant differences were found in the prevalence of the other investigated thrombophilic factors. In all, 37.9% patients without acquired risk factors were positive for at least 1 thrombophilic factor compared with 7.6% RVO patients with acquired risk factors (p < 0.001) and 8.3% of the controls (p < 0.001). There was no significant difference in the prevalence of thrombophilic disorders among RVO patients according to age.

CONCLUSIONS

FV Leiden is significantly more frequent among RVO patients without acquired risk factors. Thrombophilia plays a much more important role in the pathogenesis of RVO in patients without acquired risk factors. Screening for thrombophilia is thus indicated only for patients in whom these factors have been excluded.

In retinal vein occlusion platelet response to thrombin is increased

INTRODUCTION

Retinal vein occlusion is a major cause of ocular morbidity. The precise mechanism leading to thrombosis in retinal vein occlusion has not yet been clearly elucidated. Several risk factors have been identified, including hypertension diabetes, history of cardiovascular disease, hypercholesterolemia, hyperhomocysteinaemia, increased ocular pressure and glaucoma. Although thrombus formation in the vein plays a significant role in the onset of retinal vein occlusion, the relationship between platelet aggregation and retinal vein occlusion remains to be clarified.

MATERIALS AND METHODS

In the present study the platelet response to thrombin in a selected group of retinal vein occlusion patients was investigated. Retinal vein occlusion patients 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 total protein tyrosine phosphorylation, p38MAPK and cytosolic phospholipase A(2) phosphorylation, arachidonic acid release, intracellular calcium levels, thromboxane B(2) and superoxide anion formation were measured.

RESULTS

Results show that platelets of patients were more responsive to thrombin than healthy subjects. In resting or in thrombin stimulated platelets of patients total protein tyrosine phosphorylation, p38MAPK and cytosolic phospholipase A(2) phosphorylation were increased. Also arachidonic acid release, thromboxane B(2) and superoxide anion formation were higher in patients than in healthy subjects. In addition intracellular calcium rise induced by thrombin was increased in patients.

CONCLUSIONS

Altogether data suggest that platelet hyperaggregability inducing thrombus formation might be an important factor in the onset and/or development of retinal vein occlusion.

Ocular vascular thrombotic events: a diagnostic window to familial thrombophilia (compound factor V Leiden and prothrombin gene heterozygosity) and thrombosis

In a 12-member, 3-generation kindred with conjoint inheritance of G1691A factor V Leiden (FVL) and G20210A prothrombin gene (PTG) mutations, identified through a proband with amaurosis fugax and his father with nonarteritic ischemic optic neuropathy (NAION), the authors' hypothesis was that ocular thrombosis was a diagnostic window to familial thrombophilia-thrombosis. The authors used polymerase chain reaction (PCR) measures for thrombophilia (FVL, PTG, C677T-A1298C methylenetetrahydrofolate reductase [MTHFR], platelet glycoprotein PLA1A2) and hypofibrinolysis (plasminogen activator inhibitor-1 4G4G). The 39-year-old white male proband, with amaurosis fugax and transient ischemic attacks (TIA), was found to be a compound heterozygote for FVL and PTG mutations. His symptoms resolved only after coumadin. His 44-year-old brother (deep venous thrombosis [DVT]) and 46-year-old sister (DVT, pulmonary embolus [PE]) were compound FVL-PTG gene heterozygotes. Of 4 asymptomatic children born to these 3 siblings, 2 were FVL heterozygotes and 2 PTG heterozygotes. The proband's 69-year-old father, with NAION and ischemic stroke, had PTG heterozygosity, familial high factor VIII, and compound MTHFR C677T-A1298C mutation with homocysteinemia. The proband's 61-year-old aunt had PTG heterozygosity, recurrent DVT, and mesenteric artery thrombosis. The proband's 67-year-old mother, free of thrombotic events, was a FVL heterozygote, had high factor VIII, and PAI-1 4G4G homozygosity. In this extended kindred, ocular thrombotic events (amaurosis fugax, NAION) were associated with variegated thrombotic events, including TIA, ischemic stroke, DVT, PE, and mesenteric artery thrombosis, and opened a diagnostic window to family screening and treatment for complex thrombophilias, which had previously been undiagnosed.

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

PURPOSE

Atherosclerotic and thrombophilic risk factors may be causes of central retinal vein occlusion (CRVO). The aim of this study was to evaluate the prevalence of the aforesaid risk factors in patients with recurrent CRVOs and patients with a single episode of CRVO.

METHODS

Seventeen patients with recurrent CRVO and 30 with a single episode of CRVO were enrolled. The atherosclerotic risk factors investigated were hypertension, diabetes, smoking, and dyslipidemia. Specific laboratory tests for the following thrombophilic markers were performed: homocystinemia (Hcy), lipoprotein (a), factor VIII, factor II G20210A and factor V G1691A polymorphisms, lupus anticoagulant, anticardiolipin antibodies, plasminogen activator inhibitor-1, and deficit of vitamins B6, B12, and folic acid. A multivariate analysis, adjusted for age, gender, traditional and thrombophilic risk factors, was performed. Statistical significance was set at p<or=0.05.

RESULTS

Hypercholesterolemia, hypertriglyceridemia, fasting, and postmethionine hyperhomocysteinemia (HHcy) were more prevalent in recurrent CRVO patients (p<0.001, p<0.001, p=0.006, and p=0.005, respectively). At multivariate analysis, hypercholesterolemia (OR: 5.04, 95% CI 1.39-18.17; p=0.025), hypertriglyceridemia (OR: 5.60, 95% CI 1.52-20.61; p=0.017), fasting HHcy (OR: 5.77, 95% CI 1.39-23.89; p=0.028), and postmethionine HHcy (OR: 10.88, 95% CI 2.50-47.42; p=0.002) were found to be significantly associated with recurrent CRVO.

CONCLUSIONS

Dyslipidemia and hyperhomocysteinemia are independent risk factors for the occurrence of recurrent CRVO. A complete assessment of atherosclerotic and thrombophilic risk factors in CRVO patients. In addition, the need for a specific treatment is suggested.

Branch retinal vein occlusion: pathogenesis, visual prognosis, and treatment modalities

In branch retinal vein occlusion (BRVO), abnormal arteriovenous crossing with vein compression, degenerative changes of the vessel wall and abnormal hematological factors constitute the primary mechanism of vessel occlusion. In general, BRVO has a good prognosis: 50-60% of eyes are reported to have a final visual acuity (VA) of 20/40 or better even without treatment. One important prognostic factor for final VA appears to be the initial VA. Grid laser photocoagulation is an established treatment for macular edema in a particular group of patients with BRVO, while promising results for this condition are shown by intravitreal application of steroids or new vascular endothelial growth factor inhibitors. Vitrectomy with or without arteriovenous sheathotomy combined with removal of the internal limiting membrane may improve vision in eyes with macular edema which are unresponsive to or ineligible for laser treatment.

Ocular vascular thrombotic events: central retinal vein and central retinal artery occlusions

We prospectively assessed associations of thrombophilia- hypofibrinolysis with central retinal vein occlusion (CRVO) (40 patients) and central retinal artery occlusion (CRAO) (9 patients). We used polymerase chain reaction measures for thrombophilia (factor V Leiden, prothrombin, C677T MTHFR, platelet glycoprotein PlA1/A2) and hypofibrinolysis (plasminogen activator inhibitor-1 4G4G). Serologic thrombophilia measures included protein C, protein S (total and free) and antithrombin III, homocysteine, lupus anticoagulant, anticardiolipin antibodies IgG-IgM, and factors VIII and XI. Serologic hypofibrinolysis measures included Lp(a) and plasminogen activator inhibitor activity. For comparison with 40 CRVO and 9 CRAO patients, 80 and 45 race-gender matched controls were studied. The factor V mutation was more common in CRVO (3/40, 8%) than controls (0/79, 0%), P = .036, as was high (>150%) factor VIII (12/40, 30%) versus (4/77, 5%), P = .0002. Low antithrombin III (<80%) was more common in CRVO (5/39, 13%) than in controls (2/73, 3%), P = .049. Homocysteine was high (> or =13.5 micromol/L) in 5/39 (13%) CRVO patients versus 2/78 controls (3%), P = .04. Three of 9 CRAO patients (33%) had low (<73%) protein C versus 2/37 controls (5%), P = .044. Two of 9 CRAO patients (22%) had high (> or =13.5 micromol/L) homocysteine versus 0/42 controls (0%), P =. 028. Four of 9 CRAO patients had the lupus anticoagulant (44%) versus 4/33 (12%) controls (P = .050). CRVO is associated with familial thrombophilia (factor V Leiden, factor VIII, low antithrombin III, homocysteinemia), and CRAO is associated with familial and acquired thrombophilia (low protein C, homocysteinemia, lupus anticoagulant), providing avenues for thromboprophylaxis, and triggering family screening.

Gain-of-function gene mutations and venous thromboembolism: distinct roles in different clinical settings

OBJECTIVE

To calculate the prevalence of common gain of function gene mutations in patients with different clinical manifestations of venous thromboembolism.

DESIGN AND SETTING

Case-control study in two hospitals in Italy.

PARTICIPANTS

387 patients with venous thromboembolism and 286 controls.

MAIN MEASURES

Factor V (FV) Leiden, factor II (FII) A20210 and JAK2 V617F mutations.

RESULTS

Among patients with deep vein thrombosis in one leg, 23 (20.9%) carried FV Leiden and FII A20210 mutations. Similar figures were observed in patients with cerebral vein thrombosis (CVT; n = 9; 20.0%) and in patients presenting with splanchnic vein thrombosis (SVT; n = 26; 18.7%). A lower prevalence was obtained in patients with retinal vein thrombosis (n = 11; 11.8%). The JAK2 F617 mutant allele was found in 27 (21.1%) patients with SVT, but in none of the patients presenting with a thrombotic event from different districts. 13 of the 27 JAK2 V617F-positive subjects with SVT were previously known to have a myeloproliferative disease (MPD). Three other patients had a diagnosis of MPD after the occurrence of the thrombotic event.

CONCLUSION

Carriership of FV Leiden or FII A20210 mutations identifies an at-risk condition for venous thrombosis in the lower extremities, SVT or CVT. In patients with SVT, screening for the JAK2 V617F mutation may be useful in recognising patients who should be carefully observed for the subsequent development of overt MPD. Thus, genetic tests may play a different role, various clinical manifestations of venous thromboembolism being associated with distinct risk profiles.