頚動脈ステント留置術後に多発性分節性脳血管攣縮による低灌流で脳梗塞を合併した1例

Possible Cerebral Infarction due to Multiple Segmental Cerebral Vasospasms after Carotid Artery Stenting:A Case Report

Ⅰ．はじめに

　頚動脈ステント留置術（carotid artery stenting：CAS）の合併症として，術中や術後にプラークより生じる血栓塞栓症による脳虚血性合併症や過灌流症候群による症状がよく知られている．また，血圧低下，徐脈，脳血管攣縮などが原因で低灌流となる遅発性脳虚血性合併症が起こることも指摘されている．これらは，入院期間中に症状の改善を認めることが多く，臨床経過のみからは過灌流症候群などと鑑別することが困難で，十分には認識されていない．今回，われわれは症候性両側頚部内頚動脈狭窄症に対し右側CASを施行したところ，術後2日に左大脳半球の著明な低灌流による意識障害，片麻痺，運動失語症状が出現した症例を経験した．脳虚血症状出現時，頭部MRAでは両側脳血管に多発性，分節状の狭窄を認めた．1週間の昇圧で症状は改善し，分節状の狭窄は4週間で消失した．この経過からCAS術後に一過性に多発性分節性脳血管攣縮による低灌流を来したと考えた．過灌流症候群と反対の病態であるが，早急に対処すべき病態と考え報告する．

　A 62-year-old man was admitted due to consciousness disturbance and motor aphasia. Magnetic resonance（MR）images demonstrated watershed infarctions in the territory of the left middle cerebral artery, occlusion of the left internal carotid artery, and severe stenosis of the right internal carotid artery at the neck. He was treated with a recombinant tissue plasminogen activator. One month later, angiography revealed recanalization of the left internal carotid artery with residual severe stenosis at the neck. We attempted carotid artery stenting（CAS）on the left internal carotid artery, but could not pass the guide wire through the stenosis. Therefore, we performed CAS on the right carotid artery instead. At the second day after CAS, the patient showed consciousness disturbance, right hemiparesis, and motor aphasia. MR images showed a new infarction in the left cerebral hemisphere and bilateral multifocal segmental arterial constrictions. By keeping his blood pressure at a high enough level for one week, his symptoms were relieved, and MR images showed resolution of the vessel constrictions. From this case, we can conclude that this kind of multiple segmental vasospasms after CAS require contrasting treatments to those for hyperperfusion syndrome. Interventionalists should be aware of this condition and its treatments.