Abstract and Introduction
Abstract
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/m2] 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.
Introduction
In recent years, knowledge of the pathophysiology and risk factors for retinal vein occlusion (RVO) has aroused great interest since they represent potential advances in prophylaxis and treatment.[1–3] Retinal vein occlusion is the most common retinal vascular disease after diabetic retinopathy. The occlusion can occur both at the level of the central retinal vein (CRVO) adjacent to the lamina cribrosa of the optic nerve, as well as at the distal retinal branches (BRVO) typically in arteriovenous intersections. Central retinal vein occlusion is a common cause of unilateral sight loss, and BRVO can produce different levels of visual impairment which generally progress during the natural evolution of the disease.[4]
The real incidence of RVO is difficult to assess because of the high percentage of asymptomatic cases that only are discovered a posteriori, when RVO occur. For Fontela et al.,[5] this incidence would be 2.14/1000 patients for a population over 40 years and 5.36/1000 in one over the age of 64. It is estimated that around 16 million people in the world may have RVO in at least one eye.[6,7] Branch retinal vein occlusion is four times more frequent than is CRVO, and the bilateral event rate is very rare, accounting for 5% of cases.[3,4,8]
Systemic and local factors have been implicated in RVO. Among the local factors, short longitudinal axis, open-angle glaucoma and ocular hypertension are all situations that could compromise retinal venous flow. The potential role of thrombophilia including proteins C and S, antithrombin III deficiencies, Factor V Leiden, hyperhomocysteinaemia and antiphospholipid syndrome (APS) has been analysed in several studies.[9–11] Branch retinal vein occlusion at the junction of sclerotic arteries highlights the importance of arterial risk factors in the aetiology of RVO and, therefore, numerous studies have assessed the possible role of hypertension, dyslipidaemia, obesity and diabetes.[11]
Retinal bleeding, oedema and neovascularisation of the iris, anterior chamber angle and of the retina are all complications of the RVO leading to a partial or total loss of sight.[3,12]
Related to the therapy of RVO, some local treatments such as laser photocoagulation,[13,14] corticoids[15,16] or vascular endothelial growth factor (VEGF) inhibitors[17] had been applied. Among the general treatments: isovolemic haemodilution,[18] antiplatelet drugs,[19–21] low molecular weight heparins[20,21] and fibrinolytics[22] had all been used with different results. Although the evidence is still scarce, the results of some of the above-mentioned studies might suggest that LMWH can be superior to other general treatments.[1]
However, none of them is totally effective,[23,24] so a good prophylaxis achieved by a thorough knowledge of the associated risk factors is needed in order to decrease the incidence of RVO.
Taking into account the magnitude of the problem and the necessity of preventive actions, our aim is not only to describe the risk factors already present in a consecutive series of patients with RVO, but also to compare the levels and prevalence of these risk factors with suitable populations for both arterial and venous factors.
Int J Clin Pract. 2014;68(7):871-881. © 2014 Blackwell Publishing
