The investigation of patients with retinal vascular occlusion

Retinal vessel structure measurement using spectral-domain optical coherence tomography

PURPOSE

To assess the reliability and validity of spectral-domain optical coherence tomography (SD-OCT) measurements of retinal vessel lumen diameters and wall thicknesses.

METHODS

SD-OCT was used to characterize the circular region around the optic disc of 40 eyes (20 subjects). The inner and outer sides (vitreal and choroidal sides) of the vessel wall and the luminal diameter were measured using intensity graphs.

RESULTS

Mean arterial and venous luminal diameters were 95.1±16.1 and 132.6±17.8 μm, respectively. The wall thicknesses of inner and outer sides of the artery were 23.9±4.9 and 21.2±3.5 μm, respectively. The wall thicknesses of the inner and outer sides of the vein were 20.7±4.2 and 16.3±4.3 μm, respectively. There were significant differences between the inner and outer wall thicknesses in both the artery and vein (P<0.01). Intra- and interobserver intraclass correlation coefficients (ICCs) for lumen measurements were >0.95, and for wall thicknesses were >0.85, except for the outer wall thickness measurements. The mean value of outer and inner wall thicknesses showed good reproducibility, with ICCs of >0.85.

CONCLUSION

Intensity graph-assisted measurements using SD-OCT provided more objective information in finding boundaries of vessels. Luminal diameters and wall thicknesses obtained with OCT showed good overall reproducibility, with inner wall thicknesses being thicker, and with better reproducibility compared with outer wall thicknesses, where ICC values were the lowest among the inner wall thicknesses, mean thicknesses of inner and outer walls, and luminal diameters. When using SD-OCT measurements, caution is therefore advised when using only the outer wall as representative of the wall thicknesses.

Cardiovascular and thrombophilic risk factors in patients with retinal artery occlusion

This article evaluates the prevalence of cardiovascular and thrombophilic risk factors in patients with retinal artery occlusion. Forty-one patients with a first episode of a retinal artery occlusion underwent complete ophthalmic examination, routine blood testing and specific laboratory tests for thrombophilia, such as fasting and postmethionine homocysteine, lipoprotein(a), plasminogen activator inhibitor-1, factor VIII, factor V Leiden, factor II G20210A polymorphism, lupus anticoagulant and anticardiolipin antibodies. The control population consisted of 100 healthy individuals comparable as regards age and sex. At univariate analysis, hypertension, smoking, dyslipidaemia (both high cholesterol and triglyceride levels), antiphospholipid antibodies, hyperhomocysteinaemia, elevated factor VIII and lipoprotein(a) levels were significantly associated with retinal artery occlusion; at multivariate analysis, adjusted for age, sex, traditional and thrombophilic risk factors, smoking, hypercholesterolaemia, elevated homocysteine and lipoprotein(a) levels confirmed their independent role as risk factors for retinal artery occlusion. In conclusion, the results of the present pilot study demonstrate that the prevalence of hypercholesterolaemia and smoking and the 'thrombophilic burden' are increased in patients with retinal artery occlusion. Our findings may have implications for the management of these patients, suggesting the need for an intensive and tailored secondary prevention and new therapeutic approaches.

RETINAL VASCULAR OCCLUSION IN PATIENTS INFECTED WITH HUMAN IMMUNODEFICIENCY VIRUS

PURPOSE

To describe the clinical features of retinal vascular occlusions (macrovasculopathy) and the proportion of affected patients with human immunodeficiency virus (HIV) infection.

METHODS

Retrospective chart review of all HIV-infected individuals with retinal vascular occlusions seen at a single tertiary care clinic between November 1983 and May 1998.

RESULTS

Retinal vascular occlusion was found in 38 eyes of 33 (1.3%) of the 2,484 consecutive patients examined. Of the 33 patients, 16 (48.5%) had central retinal vein occlusion, 9 (27.3%) had branch retinal vein occlusion, 4 (12.1%) had hemiretinal vein occlusion, and 1 each (3.0%) had central retinal arterial occlusion, branch retinal arterial occlusion, and combined hemiretinal vein occlusion and branch retinal artery occlusion. One patient (3.0%) had Purtscher-like retinopathy in one eye. Multiple regression analysis revealed that macrovasculopathy was associated with the presence of noninfectious retinal microvasculopathy (odds ratio, 5.76; 95% confidence interval, 2.59-12.80). Vision at the time of diagnosis ranged between 20/20 and no light perception. Twenty-five (75.8%) of the 33 patients had follow-up examinations for a mean period of 9.1 months. Ocular findings during follow-up included capillary dropout in 3 patients (11.5%), posterior pole neovascularization in 4 (15.4%), vitreous hemorrhage in 4 (15.4%), and optic atrophy in 6 (23.1%). Vision at the last eye examination ranged between 20/20 and no light perception and was 20/200 or worse in 15 (39.5%) of 38 eyes.

CONCLUSIONS

Patients with HIV infection have a small risk of retinal vascular occlusion, but complications and visual loss are common in affected patients. There is a strong association between noninfectious retinal microvasculopathy and retinal vein occlusions.

Bilateral central retinal vein occlusion with multiple intracerebral hemorrhage in a neonate

Central retinal vein occlusion and intracerebral hemorrhage are rare diseases during infancy and are both related to venous thrombosis. We present the case of a full-term male hydrops infant without specific neurologic symptoms initially but later demonstrating bilateral central retinal vein occlusion and intracerebral hemorrhage. We conclude that routine funduscopic examination in high-risk newborns should be seriously considered.

Embolic central retinal artery occlusion detected by orbital color Doppler imaging

OBJECTIVE

To describe the detection of emboli to the retrobulbar circulation using orbital color Doppler imaging in patients with central retinal artery occlusions (CRAO) without visible retinal emboli.

DESIGN

Noncomparative, retrospective, observational case series.

PATIENTS AND METHODS

Twenty-nine patients with CRAO, without funduscopic evidence of embolic material within the retinal arterioles, underwent neuroophthalmic examination and evaluation with orbital color Doppler imaging.

MAIN OUTCOME MEASURES

The detection of retrobulbar plaques using orbital color Doppler imaging.

RESULTS

Nine of 29 (31%) patients with CRAO demonstrated hyperechoic retrobulbar plaques. All nine patients had visual acuity of counting fingers or worse at presentation. Six of the nine patients (67%) had a history of hypertension, and seven (78%) had coronary artery disease as vascular risk factors for arterial occlusive disease. Two of the nine patients (22%) subsequently died from cardiac-related events.

CONCLUSIONS

This study demonstrates that orbital color Doppler imaging is an important diagnostic procedure for establishing embolism as the cause of CRAO when no emboli are visible in the retinal circulation. This noninvasive technology enables prompt differentiation of embolic disease from arterial occlusion caused by intrinsic atherosclerosis, vasospasm, or vasculitis from giant cell arteritis. Recognition of emboli has important management implications for these patients.

Monitoring of the thromboxane A2/prostacyclin ratio in the urine of patients with retinal vascular occlusion through the low-dose-aspirin therapy using the gas chromatography/selected ion monitoring method

We determined the levels of the stable urinary metabolites of thromboxane A2 and prostacyclin, 11-dehydro-thromboxane B2 (11-dehydro-TXB2) and 2,3-dinor-6-keto-prostaglandin F1alpha (2,3-dinor-6-keto-PGF1alpha) in patients with retinal vascular occlusion (RVO) to elucidate the change of the thromboxane A2/prostacyclin (TX/PGI) ratio with this disease and the effect of low-dose-aspirin therapy. 11-Dehydro-TXB2 and 2,3-dinor-6-keto-PGF1alpha were converted to 1-methyl ester-propylamide-9,12,15-tris-dimethylisopropylsilyl ether derivative and 1-methyl ester-6-methoxime-9,12,15-tris-dimethylisopropylsilyl ether derivative, respectively, and applied to a gas chromatography/selected ion monitoring. The average level of 11-dehydro-TXB2 in 30 patients with RVO was 1038 +/- 958 pg/mg creatinine. It was significantly higher than that of 27 healthy volunteers, which was 616 +/- 294 pg/mg creatinine (p < 0.05 with unpaired t-test). However, 2,3-dinor-6-keto-PGF1alpha levels were not significantly different between these two groups. The average ratio of TX/PGI in the RVO patients was 32 +/- 26 and it was significantly higher than that of healthy volunteers, 17 +/- 10 (p < 0.01). Patients with central retinal artery occlusion or branch retinal artery occlusion showed greatly high 11-dehydro-TXB2 levels and TX/PGI ratios, although the number of patients was limited in the current study. After the administration of low-dose aspirin (40 mg/day) for about 1 month, the TX/PGI ratio decreased to around the normal level. Following the levels for up to 10 months, they also remained at the normal level. These observations suggested that the 11-dehydro-TXB2 levels and the TX/PGI ratio reflect the pathological conditions of RVO and are useful markers of the treatment.

Retinopathy in systemic lupus erythematosus: pathogenesis and approach to therapy

The starting point in the assessment of SLE-retinopathy is the clinical examination by ophthalmoscopy and retinal fluorescein angiography. It is noted that two major clinical forms of retinopathy may occur in SLE; (1st) the "classic" type characterized by cotton-wool spots with or without intraretinal hemorrhages, and (2nd) the thrombosis of larger retinal blood vessels, such as central or branch arteries/veins. However, a well-defined pathogenetic classification of SLE-retinopathy has still not been proposed as yet. A practical classification based on the pathogenesis could be of aid to commence a more appropriate treatment. The aims of this paper are; (1st) to focus on the most implicate mechanisms of retinal vascular disease in SLE, (2nd) to mention the most common features associated with the different forms of retinopathy, and finally (3rd) to assess the prevalence of retinopathy in SLE. In our opinion, it seems that two major types of retinopathy exist in SLE: firstly, the Hughes' retinopathy due to antiphospholipid-induced retinal vascular thrombosis, for which anticoagulation is the best treatment, and secondly, the "classic" retinopathy in which at least two major causes could be associated; vasculitis and accelerated atherosclerosis. In patients with "classic" retinopathy, the most appropriate treatment still needs to be established. If "classic" retinopathy is due to vasculitis, immunosuppressive drugs should be administered, while if atherosclerosis play an etiologic role, a prophylaxis with antioxidants or the use of low-dose aspirin should be assessed.

Accuracy of visible retinal emboli for the detection of cardioembolic lesions requiring anticoagulation or cardiac surgery. Retinal Emboli of Cardiac Origin Study Group

AIM

To determine the accuracy of visible retinal emboli as a diagnostic "test" for the likelihood of receiving anticoagulation or cardiac surgery based on the results of transthoracic echocardiography, in the setting of acute retinal arterial occlusion.

METHODS

A multicentre retrospective diagnostic study at Kingston Eye Centre, Queen's University, Kingston, Ontario; Wills Eye Hospital, Philadelphia; Ottawa Eye Institute, Ottawa, Ontario; and the Halifax Infirmary, Halifax, Nova Scotia of 104 patients with both embolic and nonembolic acute retinal arterial obstruction who underwent transthoracic echocardiography was performed, to determine the accuracy of visible retinal emboli as a diagnostic "test" for anticoagulation or cardiac surgery. Anticoagulation or surgical intervention on the basis of abnormalities was detected solely through the technology of transthoracic echocardiography.

RESULTS

41 patients had visible retinal emboli (calcific, cholesterol, or fibrin). The remaining 63 had no evidence of embolic disease. The sensitivity of emboli for the likelihood of a patient receiving anticoagulation or cardiac surgery was 50%. The specificity, positive predictive value, and negative predictive value were 62%, 15%, and 90%, respectively. The likelihood ratio (LR = 1.31) obtained given the presence of a visible retinal embolus was neither clinically nor statistically significant (LR+ve = 1.31; 95% CI (0.91, 3.16)). This likelihood ratio, when applied to a patient with a pretest probability of 50%, results in a post-test probability of 56.7%.

CONCLUSIONS

These results demonstrate that the presence of a visible retinal embolus should not be the sole determinant of whether to order transthoracic echocardiography, as the likelihood ratio for a patient receiving anticoagulation or cardiac surgery, given the presence of a visible retinal embolus was only 1.31.

Retinal artery occlusion

A 54-year-old man presented with an acute painless loss of vision. He had a three-month history of malaise, weight loss, and episodic sweating. Physical examination showed a thin, febrile man with a petechial rash over the lower legs. Cardiac auscultation revealed an apical thrill and pansystolic murmur. Dental hygiene was poor. The diagnosis, mechanisms and treatment of retinal artery occlusion associated with bacterial endocarditis are reviewed.