Factors related to improvement of cerebrovascular reserve after superficial temporal artery to middle cerebral artery anastomosis for patients with atherosclerotic steno-occlusive disease.

Abstract

This study aimed to investigate factors related to improvement of hemodynamics and evaluated the usefulness of intraoperative Doppler for predicting postoperative hemodynamics in patients with cerebrovascular atherosclerotic steno-occlusive disease (CASD) of the internal carotid artery (ICA) or middle cerebral artery (MCA) who were treated with extracranial-intracranial (EC-IC) bypass surgery. Forty-eight patients with CASD of the ICA or MCA who were treated by superficial temporal artery to middle cerebral artery bypass with a follow-up longer than 12months were enrolled. Repeated transient ischemic attack or completed ischemic stroke was observed under optimal medical therapy in all patients. Intraoperative blood flow velocity of the MCA was evaluated by a Doppler flowmeter. Cerebral blood flow and cerebrovascular reserve (CVR) were evaluated using N-isopropyl-[123I] p-iodoamphetamine (IMP) single photon emission computed tomography (SPECT) preoperatively and 3months after surgery. Imaging and clinical data were retrospectively reviewed. CVR was significantly increased postoperatively (p = 0.03). One year after the operation, two (4.2%) patients developed cerebral infarction. The change in MCA flow velocity just after anastomosis compared with pre-anastomosis proximal and distal of the anastomosis site was a median of 3.0 and 2.6 times, respectively. However, there was no significant association between changes in intraoperative MCA flow velocity and postoperative CVR. Multivariate analysis showed that the presence of a lower estimated glomerular filtration rate (eGFR) was an independent risk factor for a decrease in CVR (p = 0.036). A higher eGFR might have prognostic value for improvement in CVR after EC-IC bypass surgery in patients with CASD and misery perfusion.