破裂急性期にバルーン閉塞試験を行い母血管閉塞が可能であった錐体部巨大内頚動脈瘤破裂の1例

Ruptured Giant Thrombosed Aneurysm at the Internal Carotid Artery Successfully Treated with Endovascular Internal Trapping Following Emergent Balloon Occlusion Test: A Case Report

Ⅰ．はじめに

　内頚動脈錐体部巨大動脈瘤は稀であるが一般的に予後不良であり，治療に難渋することが多い．直達手術，脳血管内手術いずれにおいても動脈瘤のみの処置は不可能なことが多く，母血管閉塞が行われることが多い．その場合，バルーン閉塞試験（balloon occlusion test：BOT）にて血行動態の評価が有用であることは言うまでもなく，虚血耐性が得られない症例においてはバイパス術を併用する．しかし，緊急を要する症例では迅速な判断，対応が求められる一方，耐性の有無を正確に判断することが難しい場合が多い．今回われわれは，鼻出血で発症し出血性ショックを呈した内頚動脈錐体部巨大血栓化動脈瘤に対し，緊急でBOTを行い，引き続き母血管閉塞が可能であった症例を経験したので，出血発症急性期におけるBOTのマネジメントについて文献的考察を加え報告する．

　The authors report a case of ruptured giant thrombosed aneurysm successfully treated with endovascular internal trapping following emergent balloon occlusion test (BOT),and discuss its clinical implications regarding emergent BOT.

　A 41-year-old female showing massive epistaxis was referred to our institute for the treatment of a giant aneurysm. Computed tomography and digital subtraction angiography revealed a giant thrombosed aneurysm located at the petrous portion of the right internal carotid artery with an erosion of the petrous bone. Emergent BOT was performed under the monitoring of regional oxygen saturation of the brain (rSO₂) and stump pressure as well as neurological changes and confirmed tolerance for permanent internal artery occlusion with a little change of rSO₂ and stump pressure. Endovascular internal trapping was performed with detachable coils and the postoperative course was uneventful. Magnetic resonance imaging showed a decrease in the size of the aneurysm three month after the treatment, and the aneurysm got organized four years later.

　For ruptured aneurysms,emergent BOT is sometimes difficult to perform due the neurological deterioration or inability to prepare radioisotope for single photon computed tomography. Nevertheless,monitoring of rSO₂ and stump pressure as well as neurological changes can be of help for decision making concerning the treatment strategy. Endovascular treatment following BOT is a feasible and life-saving approach for emergent management of ruptured internal carotid artery aneurysms presented with massive epistaxis.