Limit of intraoperative near-infrared spectroscopy monitoring during endovascular thrombectomy in acute ischemic stroke.

Endovascular thrombectomy is recommended for a persistent ischemic penumbra if recanalization cannot be achieved by the intravenous (IV) administration of recombinant tissue-plasminogen activator (rt-PA) alone. Although endovascular thrombectomy is a powerful treatment for major cerebral artery occlusion, the monitoring of recanalization and reperfusion during acute ischemic stroke presents a therapeutic challenge, and a previous study reported the usefulness of near-infrared spectroscopy (NIRS) for intraoperative monitoring during emergency endovascular thrombectomy for acute large ischemic stroke. Here we present our experience with a relevant case series. We applied NIRS monitoring during endovascular thrombectomy in two patients with large ischemic stroke following carotid artery occlusion and one patient with a non-large ischemic stroke caused by a distal middle cerebral artery (MCA) occlusion. In the patients with large ischemic stroke, complete recanalization of the internal carotid artery was achieved, and NIRS revealed a very good regional oxygen saturation (rSO) response. By contrast, in the patient with non-large ischemic stroke, the rSO did not change, despite complete recanalization of the distal MCA. Our findings suggest the limited usefulness of intraoperative NIRS monitoring during emergency endovascular thrombectomy for non-large acute ischemic stroke caused by a distal MCA occlusion. However, intraoperative NIRS monitoring could be used practically to detect recanalization of the major artery during thrombectomy and early IV rt-PA administration in cases involving major artery occlusion.