Primary Vascular Occlusion in IRVAN (Idiopathic Retinal Vasculitis, Aneurysms, Neuroretinitis) Syndrome

IRVAN is a rare retinal vascular disease characterized by the presence of aneurysmal dilations along the retinal arteriolar tree. Visual loss occurs from sequelae to proliferative changes or due to severe macular exudation and rarely from secondary vascular occlusion following laser photocoagulation of the aneurysms. We herein report a patient with a primary vascular occlusion in a patient with IRVAN and suggest that such patients may already have a natural predisposition to develop a vascular occlusion.

Neuroprotective effect of treatment with calcium antagonists on hypertensive retina

The influence of hypertension and of treatment with the dihydropyridine-type Ca2+ antagonists lercanidipine, manidipine, nicardipine, and nimodipine and with non dihydropyridine-type vasodilator hydralazine on retinal nervous and glial fibrillary acidic protein (GFAP) immunoreactive astrocytes were investigated in male spontaneously hypertensive rats (SHR). Normotensive Wistar-Kyoto (WKY) were used as normotensive references group. Treatment of animals with oral equi-hypotensive doses of the above compounds started at 14 weeks of age and lasted for 12 weeks. Microanatomical analysis was extended to samples of frontal cortex and occipital cortex used as reference tissue. Different compounds investigated decreased to a similar extent systolic blood pressure values with the exception of nimodipine that in spite of the high dose used exerted a less pronounced hypotensive activity. Morphological changes including reduced thickness of retina and of inner plexiform, outer nuclear and layer of inner and outer segments plus outer limiting layer, and loss of ganglionic neurons were observed. GFAP-immunoreactive astrocyte hypertrophy was also found in control SHR. These phenomena were countered by treatment by treatment with dihydropyridine-type Ca2+ antagonists and to a lesser extent by hydralazine. The different Ca2+ antagonists tested exerted a similar protective effect on retinal, but not on brain neurons. The sensitivity of retina and cerebral cortex to anti-hypertensive treatment may be related to a different density of L-type Ca2+ channels in structures investigated or to kinetic reasons. The demonstration of a neuroprotective effect of Ca2+ antagonists on retina of SHR suggests that these compounds might protect to a some extent retina from hypertensive injury.

Systemic disorders associated with retinal vascular occlusion

Occlusions of the retinal arterial and venous circulations are common causes of severe visual decline and can affect all age groups. Acute retinal arterial obstruction is often associated with critical cerebrovascular and cardiovascular disease that may require systemic treatment. Retinal venous obstruction may be the presentation of significant systemic hypertension, diabetes mellitus, and a greater risk for cardiovascular morbidity. Additional metabolic and hematologic abnormalities have been identified in patients with retinal occlusive disease. The authors review recent advances in the study of systemic conditions associated with retinal vascular occlusions and offer guidelines for appropriate medical evaluation of patients with retinal occlusive disease.

The influence of randomized trials on the use of anticoagulants for atrial fibrillation

INTRODUCTION

Anticoagulants and anti-platelet drugs have been shown in randomized trials to reduce the risk of stroke in patients with atrial fibrillation (AF). We therefore investigated their use in patients known to be in AF before a stroke, transient ischaemic attack (either cerebral or ocular) or retinal artery occlusion to assess the influence of trials on clinical practice.

METHODS

Inpatients and outpatients with acute stroke, transient ischaemic attack or retinal artery occlusion were prospectively identified by a stroke physician from 1990 to 1997. The presence or absence of AF before the vascular event, and prior use of anticoagulant and anti-platelet drugs were recorded at the time of the assessment and verified using information from general practitioner and hospital case notes.

RESULTS

Of 1934 patients with stroke or retinal artery occlusion, 191 (10%) were in AF before their ischaemic event. Anticoagulants had been used in 40 (21%) of these, but only in 32 (2%) of the 1743 patients in sinus rhythm [odds ratio (OR) 14.2, 95% confidence interval (CI) 8.6-23.2]. Anti-platelet drugs had been used in 62 (32%) of those with AF compared with 500 (30%) of those in sinus rhythm (OR 1.2, 95% CI 0.9-1.64). Of the 161 patients in AF without contraindications to anticoagulants, only 36 (22%) were taking them. Although there was a statistically significant increase in anticoagulant use from 8% in 1990 to 23% in 1996, this could be explained solely by a fall in the age of the patients referred to our hospital.

CONCLUSION

Anticoagulation is probably under-used in AF. We found no conclusive evidence that anticoagulation trials have influenced clinical practice. This raises issues about the dissemination and implementation of trial results.

[Mitral valve prolapse. A possible cause of retinal vascular occlusion in young patients]

Retinal vessel occlusion in the elderly is considered to be of arteriosclerotic etiology, but in young patients the reasons for retinal vessel occlusions are manifold and much more obscure. We report on five patients under the age of 45 years who had retinal artery occlusion or retinal vein obstruction. A detailed general investigation revealed nothing but an identical cardiac abnormality in all five cases: mitral valve prolapse (MVP). A potential explanation for the coincidence of retinal vessel occlusion and MVP might be local hyperaggregability of platelets generated by the prolapsing mitral valve. In conclusion, to prevent retinal vessel occlusion from recurring in patients with proven MVP, medication containing platelet aggregation inhibitors should be given.