厳格な術後血圧管理にもかかわらず術後過灌流により遅発性脳出血を呈したもやもや病の1例

Asymptomatic Intracerebral Hemorrhage under Strict Blood Pressure Control due to Postoperative Cerebral Hyperperfusion in a Patient with Moyamoya Disease

Ⅰ．はじめに

　もやもや病は両側内頚動脈終末部，前および中大脳動脈近位部が進行性に狭窄・閉塞し，その付近に異常血管網の発達を認める原因不明の疾患である¹⁴⁾．浅側頭動脈・中大脳動脈（STA-MCA）吻合術は本疾患による脳虚血を改善するための確立した治療法であるが⁹⁾，もやもや病に対する直接バイパス術後急性期の潜在的合併症として過灌流症候群が注目されている^{1-3,5,6,8,11,12)}．

　われわれは，2004年3月以降もやもや病にてバイパス術を行った全症例に対して術後急性期にN-isopropyl-p-¹²³I-Iodoamphetamine SPECT（¹²³I-IMP-SPECT）による脳血流の評価を行い，バイパス吻合部位周囲の局所的高灌流が虚血発作に類似した一過性局所神経脱落症状や術後遅発性の頭蓋内出血の原因となっていることを報告してきた^1-3)．さらに，術後過灌流症候群は動脈硬化性閉塞性脳血管障害患者と比較し，もやもや病において有意に高頻度であることを明らかにした⁵⁾．今回，われわれは，術直後より過灌流症候群予防のために厳格な血圧管理を行ったにもかかわらず，無症候性の遅発性脳出血を呈したもやもや病の1例を経験したので報告する．

　We report a case of moyamoya disease manifesting as asymptomatic intracerebral hemorrhage due to postoperative cerebral hyperperfusion,despite the prophylactic intensive blood pressure control. This 35-year-old man initially suffered from right upper quadrantanopsia and was found to have cerebral infarction in the left occipital lobe due to moyamoya disease. He also manifested preoperatively a small intracerebral hemorrhage at the left caudate nucleus. The left cerebral hemisphere showed apparent hemodynamic compromise,thus he underwent left superficial temporal artery-middle cerebral artery (STA-MCA) anastomosis with indirect pial synangiosis. He was subjected to prophylactic strict blood pressure control postoperatively to avoid hyperperfusion syndrome. The N-isopropyl-p-¹²³I-Iodoamphetamine SPECT (¹²³I-IMP-SPECT) 1 day after surgery showed intense increase in cerebral blood flow (CBF) at the site of the anastomosis,and further blood pressure lowering was attempted. He did not suffer from neurologic deterioration during the postoperative period,while computed tomography (CT) 7 days after surgery revealed asymptomatic intracerebral hematoma (ICH) at the subcortex under the site of the anastomosis. Cerebral hyperperfusion is a potential complication of revascularization surgery for moyamoya disease. Accurate diagnosis and proper management of hyperperfusion are essential to avoid deleterious neurologic event due to hyperperfusion.