Persistent primitive proatlantal arteryの狭窄により脳梗塞を発症した症例に対するステント術

Stenting for Cerebral Infarction due to Stenosis of a Persistent Primitive Proatlantal Artery: A Case Report

Ⅰ．はじめに

　原始遺残動脈にはtrigeminal artery, otic artery, hypoglossal artery, proatlantal arteryがあり，胎生期を過ぎても存在している症例に関して多くの報告がなされている^{1,3,6,7,9,11,12)}．原始遺残動脈は通常吻合血管として機能しており，内外頚動脈や椎骨脳底動脈あるいは後頭動脈側の血管に障害を来した場合には，側副血行として機能する半面，血行力学的原因から動脈瘤を合併したとの報告も認められる^1,7,8,10)．

　今回われわれは，原始遺残動脈の1種であるpersistent primitive proatlantal artery（PPPA）の起始部狭窄病変が原因と推測される脳梗塞発症例に対し，ステント治療を行うことで良好な経過を得た1例を経験した．原始遺残動脈自体に対し血管内治療を行った症例は過去に報告例がなく，非常に稀な治療例であると思われる．

　Cerebrovascular disorders complicated by persistent primitive arteries are commonly reported, but, we herein present a 78-year-old man with cerebral infarction due to stenosis of a persistent primitive artery by itself. Cerebral angiography revealed bilateral vertebral artery aplasia to be complicated by a persistent primitive proatlantal artery which had become an important collateral circulation pathway. While the patient was hospitalized because of mild sensory impairment, he also developed visual field constriction and cerebellar symptoms due to recurrent stroke despite anticoagulation treatment. Based on the results of various examinations, cerebral embolism, probably caused by stenosis at the origin of the persistent proatlantal artery, was diagnosed. Carotid artery stenting for the stenosis was planned. A filter protection device was found to be very useful for stenting with maintenance of blood flow in the persistent primitive proatlantal artery. There have been no reports of stenting in persistent primitive proatlantal arteries, such as that our present case is considers. It provides valuable information on the management of this rare disorder.