解離性後大脳動脈瘤に対してステント併用コイル塞栓術を施行した1例

Stent-Assisted Coil Embolization of a Dissecting Aneurysm of the Posterior Cerebral Artery:A Case Report

Ⅰ．はじめに

　後大脳動脈瘤（posterior cerebral artery aneurysm：PCAAN）は全脳動脈瘤の0.7〜3%と稀である⁵⁾．また，PCAANは前方循環系の動脈瘤と比べて解離性動脈瘤が多いとされているが，その多くはP2 segmentに発生し，P1 segmentの解離性動脈瘤の報告は少ない¹⁵⁾．この部位は解剖学的特性から治療方法や手技に関しても議論の分かれるところである¹⁵⁾．今回われわれは，破裂解離性PCAANに対し，亜急性期にステント併用コイル塞栓術を施行した1例を経験したので，文献的考察を加えて報告する．

　Dissecting aneurysms of the posterior cerebral artery（PCA）are rare, especially those at the P1 segment. Here, we describe the case of a 57-year-old woman with a subarachnoid hemorrhage（SAH). Computed tomography angiography（CTA）and digital subtraction angiography（DSA）revealed a small（3mm）dissecting aneurysm with the typical pearl-and-string sign at the right P1 segment. Fourteen days after onset, the patient developed aphasia. DSA revealed vasospasm of the right middle cerebral artery, and we performed endovascular treatment by the intra-arterial injection of 1-(5-isoquinolinesulfonyl）homopiperazine. After this treatment, the patient's symptoms recovered immediately. Vertebral angiography revealed enlargement of the dissecting aneurysm（up to 7mm diameter). We started a loading dose of 300mg aspirin and 400mg clopidogrel after observing growth of the aneurysm. Fifteen days after onset, we performed a stent-assisted coil embolization, and obtained nearly complete obliteration of the aneurysm with preserved patency of the parent artery. Six-month follow-up DSA demonstrated complete occlusion of the aneurysm with good patency of the stented PCA；the patient was at modified Rankin Scale 1. In the treatment of ruptured dissecting aneurysms, parent vessel occlusion（PVO）with aneurysm is common. However, PVO may cause both cerebral infarction of the distal area and perforator occlusion of the occluded vessel. Stent-assisted coil embolization can preserve parent vessel flow and obliterate the aneurysm. Stents offer a therapeutic alternative for PCA dissecting aneurysms, especially when PVO cannot be tolerated.