Quinze-Vingts Hospital, DHU SightMaintain, INSERM-DHOS CIC 1423, Paris, F-75012 and Université Pierre et Marie Curie-Paris 6, Paris, France.
Institut Supérieur d'Electronique de Paris, Paris, France.
JAMA Ophthalmol. 2015 Aug;133(8):947-50. doi: 10.1001/jamaophthalmol.2015.1132.
Arteriovenous nickings (AVNs) in the retina are the cause of retinal vein occlusions and are also surrogates of cerebrovascular aging. The prevalent mechanistic model of AVNs stating that arteries crush veins remains somewhat unchallenged despite the lack of evidence other than fundus photographs. Here, we observed that venous nicking may be observed in the absence of physical contact with an arteriole.
This observational study, conducted from January 2013 to September 2014, included 7 patients showing remodeling of a venous segment close to a retinal arteriole without arteriovenous overlap were imaged by adaptive optics imaging. Affected venous segments showed a variable association of nicking, narrowing, deviation, and opacification. Venous segments were deviated toward the arterioles in 6 of the 7 cases. The degree of venous narrowing ranged from 40% to 77%, while at these sites, the width of the intervascular space ranged from 16 µm to 42 µm. Similar features were identified in typical AVNs.
Arteriovenous nickings do not necessarily involve an arteriovenous compression. Instead, the topology of venous changes suggests a retractile process originating in the intervascular space. These findings have important implications for the understanding of retinal vein occlusions and of cerebrovascular aging.
视网膜动静脉吻合（AVN）是视网膜静脉阻塞的原因，也是脑血管老化的替代标志物。尽管除眼底照片外缺乏其他证据，但动脉压迫静脉的普遍机制模型仍然存在一些争议。在这里，我们观察到，在没有与小动脉物理接触的情况下，可能会观察到静脉吻合。
这项观察性研究于 2013 年 1 月至 2014 年 9 月进行，包括 7 名患者，他们的视网膜小动脉附近的静脉段发生重塑，但没有动静脉重叠，通过自适应光学成像进行了成像。受影响的静脉段显示吻合、变窄、偏离和混浊的可变关联。在 7 例中有 6 例静脉段向小动脉偏离。静脉狭窄程度从 40%到 77%不等，而在这些部位，血管间空间的宽度从 16 µm 到 42 µm 不等。在典型的 AVN 中也发现了类似的特征。
动静脉吻合不一定涉及动静脉压迫。相反，静脉变化的拓扑结构表明，源自血管间空间的退缩过程。这些发现对理解视网膜静脉阻塞和脑血管老化具有重要意义。
