網膜血管病での動静脈短絡

Arteriovenous shunt in retinal vascular diseases

　閉塞性網膜血管病494眼の螢光眼底造影所見の解析の結果，網膜中心静脈閉塞症2眼，網膜中心動脈閉塞症2眼，網膜粟粒血管瘤症2眼で動静脈短絡路を同定した。これまでの脈なし病，糖尿病性網膜症，網膜静脈分枝閉塞症での動静脈短絡路の観察と合わせ，動静脈短絡路の形成過程と発生病態に関する共通因子を検討した。動静脈短絡路の形成過程には，優先血行路を介するものと，動静脈交叉部での吻合によるものが観察された。優先血行路形成には，動静脈間の圧落差の低下が関係しており．動静脈吻合形成には，血管壁の脆弱化が関係していると考えられた。動静脈短絡路は，多数の病的状態で網膜血管がとる基本的な血管反応のひとつであると結論される。

We observed, in previous studies, frequent arter-iovenous shunt formation in Takayasu's disease, diabetic retinopathy and branch retinal vein occlu-sion. We reviewed fluorescein angiograms in 494 eyes with other retinal vascular diseases. We paid particular attention to locate arteriovenous shunts in the retina. We could identify functional arter-iovenous shunts in 6 eyes: 2 eyes with central retinal vein occlusion, 2 eyes with central retinal artery occlusion and 2 eyes with retinal miliary angiomatosis. These shunts were formed either through development of preferential circulatory channels or through anastomosis at arteriovenous crossings.

There were two common underlying features in these six diseases with arteriovenous shunts in the retina: a decrease in arteriovenous pressure head and fragility of the retinal vascular wall. The for-mer would facilitate formation of preferential channels and the latter anastomosis at the arterio-venous crossings. We postulate that arteriovenous shunt formation is one of the basic patterns of retinal vascular reaction in pathological circum-stances.