頚動脈ステント留置術後の過灌流症候群のモニタリングに経頭蓋カラードプラ検査による左右比が有用であった1例

Left to Right Ratio of Transcranial Color-coded Sonography for Monitoring Hyperperfusion Syndrome after Carotid Artery Stenting: A Case Report

Ⅰ．はじめに

　頚動脈内膜剝離術（carotid endarterectomy：CEA）や頚動脈ステント留置術（carotid artery stenting：CAS）後の過灌流症候群の頻度は低いが致死的な頭蓋内出血につながるため，早期の発症予測や発症時の周術期管理が重要となる．過灌流のモニタリングとして経頭蓋カラードプラ（transcranial color-coded sonography：TCCS）による患側の中大脳動脈（middle cerebral artery：MCA）の平均血流速度の術前値との比（術前比）が有用である¹⁾．今回，われわれはCAS後過灌流症候群のモニタリングとしてTCCSを使用し術前比に加え左右比も考慮することにより，有効な周術期管理を行い得た症例を経験したので報告する．われわれが渉猟し得た限りでは，TCCSの左右比の有用性を示したのは本論文が初めてである．

　Hyperperfusion syndrome is a significant complication after carotid endarterectomy (CEA) or carotid artery stenting (CAS). A few reports have shown that an increase in the ratio of mean flow velocity (MFV) of the middle cerebral artery (MCA) of the affected side by transcranial color-coded sonography (TCCS) is useful for the evaluation of hyperperfusion after CEA or CAS. We report a case of hyperperfusion syndrome after CAS in which not only the increased ratio of the affected side based on preoperative mean flow velocity,but also the left to right ratio (L/R ratio) was useful for monitoring hyperperfusion. A 48-year-old man was admitted to our hospital because of cerebral infarction of the right internal carotid artery (ICA) due to stenosis of the right ICA at origin. The preoperative L/R ratio of MFV of the MCA by TCCS was 0.58. We performed CAS and the patient then developed hyperperfusion syndrome with epilepsy and was intubated under the management of strict blood control. We performed TCCS daily and the patient was extubated when the L/R ratio of MFV of the MCA decreased to 1.1 from a maximum of 2.6,although the increased ratio of MFV of the MCA of the affected side was still higher than 1.4. The patient went home without any complications from hyperperfusion. When there is preoperative laterality of cerebral blood flow,the L/R ratio of MFV by TCCS can be useful for monitoring hyperperfusion after CEA or CAS.