Cerebral hyperperfusion after carotid endarterctomy is associated with preoperative hemodynamic impairment and intraoperative cerebral ischemia

Abstract

The aim of this study was to investigate whether postoperative hyperperfusion is associated with preoperative cerebral hemodynamic impairment due to chronic ischemia and with acute cerebral ischemia during clamping of the internal carotid artery (ICA) during carotid endarterectomy (CEA). Transcranial cerebral oxygen saturation (SO₂) was monitored intraoperatively using near-infrared spectroscopy in 89 patients undergoing CEA for ipsilateral ICA stenosis (>70%). Cerebral blood flow (CBF) and cerebrovascular reserve capacity (CVRC) to acetazolamide were also measured using singlephoton emission computed-tomography (SPECT) before CEA. In addition, CBF was measured immediately after CEA. Hyperperfusion (CBF increase >100% compared with preoperative values) was observed immediately after CEA in 10 of 18 patients (56%) with reduced preoperative CVRC. Also, post-CEA hyperperfusion was observed in 9 of 16 patients (56%) whose SO₂ during clamping of the ICA decreased to less than 90% of the pre-clamping value. Logistic regression analysis demonstrated that reduced preoperative CVRC and reduced SO₂ during ICA clamping were significant independent predictors of the development of hyperperfusion immediately after CEA. In fact, all patients with reduced preoperat ive CVRC and reduced SO₂ dur ing ICA clamping developed post-CEA hyperperfusion.