近赤外線スペクトロスコピーを用いて頚動脈ステント留置術後過灌流現象を評価する妥当性についての検証

Abstract

Hyperperfusion syndrome is a complication of carotid artery stenting (CAS) that leads to a poor outcome. Therefore, prevention of hyperperfusion syndrome is important in the perioperative management of CAS. We performed CAS under general anesthesia with both proximal balloon protection and distal filter protection. We used the Invos system to monitor regional cerebral oxygen saturation (rSO2) for 2 days after CAS. Although the Invos system provides continuous and less-invasive monitoring, rSO2 values may be influenced by the patient's respiratory or circulatory conditions. In this study, we compared perioperative rSO2 monitoring and single-photon emission computed tomography (SPECT) imaging, and report the efficacy of rSO2 monitoring in predicting hyperperfusion syndrome.Methods: SPECT was performed before and one day after CAS; rSO2 monitoring was continuously performed from immediately before induction of general anesthesia until two days after CAS.Results: In total, 44 patients underwent 49 CAS operations at our institution between January 2012 and December 2013. One patient who did not undergo SPECT imaging 1 day after CAS was excluded. The median age of all patients was 74 years and 88% patients were male. One patient experienced asymptomatic subarachnoid hemorrhage after CAS. According to the SPECT imaging results, hyperperfusion phenomenon was diagnosed in 4 patients, in 3 of whom the increase in the ratio of rSO2 on balloon deflation was above 0.2 and the decrease in ratio of rSO2 on balloon inflation was below 0.15. In one of these 4 patients, compared to the preoperative status, the difference between ipsilateral rSO2 and contralateral rSO2 increased by more than 5% after CAS.Conclusion: A change in the rSO2 ratio by proximal balloon protection could be one of the indices of hyperperfusion phenomenon. In some cases, rSO2 monitoring alone may not detect hyperperfusion. Therefore, another method such as SPECT imaging may be used in combination with rSO2 to detect hyperperfusion syndrome after CAS.