Concentration of Matrix Metalloproteinase-9 in the Jugular Bulb during Carotid Endarterectomy Correlates with Severity of Intraoperative Cerebral Ischemia

Abstract

Background: Matrix metalloproteinase (MMP)-9 targets major components of the basal lamina of cerebral blood vessels and is a biochemical marker of blood-brain barrier disruption. The goal of this study was to determine whether plasma concentrations of MMP-9 in the jugular bulb during carotid endarterectomy (CEA) correlate with severity of intraoperative cerebral ischemia. Methods:In 41 patients undergoing CEA for ipsilateral internal carotid artery (ICA) stenosis, plasma samples for measurement of MMP-9 concentration were intraoperatively obtained from a venous catheter inserted into the ipsilateral jugular bulb. Transcranial cerebral oxygen saturation using near-infrared spectroscopy was also monitored intraoperatively to assess the severity of the ischemic insult during ICA clamping. Results: The MMP-9 concentrations were significantly higher after ICA declamping than before ICA clamping (p = 0.0023). A strong linear correlation was observed between the severity of the ischemic insult during carotid clamping and the increase in MMP-9 levels after ICA declamping (r = 0.776; p < 0.0001). At the postoperative neurological assessment, 3 patients showed transient minor neurological deficits. The MMP-9 level in the jugular bulb after ICA declamping was increased in patients with postoperative transient neurological deficits relative to those without. Conclusions: The concentration of MMP-9 in the jugular bulb during CEA correlates with the severity of intraoperative cerebral ischemia.