title: Reduced middle cerebral artery velocity during cross-clamp predicts cognitive dysfunction after carotid endarterectomy.
abstract: Transcranial Doppler (TCD) is a useful monitor that can be utilized during carotid endarterectomy (CEA). Cognitive dysfunction is a subtler and more common form of neurologic injury than stroke. We aimed to determine whether reduced middle cerebral artery (MCA) mean velocity (MV) predicts cognitive dysfunction and if so, whether a threshold of increased risk of cognitive dysfunction can be identified. One hundred twenty-four CEA patients were included in this observational study and neuropsychometrically evaluated preoperatively and 24 hours postoperatively. MCA-MV was measured by TCD and percentage of baseline during cross-clamp was calculated (MV(cross-clamp)/MV(baseline)). Patients with cognitive dysfunction had significantly lower MV during cross-clamp than those without cognitive dysfunction (33.1 ± 13.7 cm/s versus 39.6 ± 16.0 cm/s, p=0.02). In the final multivariate model, each percent reduction in MV was significantly associated with greater risk of cognitive dysfunction (odds ratio [OR]: 0.05 [95% confidence interval {CI} 0.01-0.23], p < 0.001) while statin use was associated with lower risk (OR: 0.33 [95% CI 0.12-0.92], p = 0.03). Using receiver operator characteristic curve analysis, the Youden index identified 72% of baseline MV during cross-clamp as the cutoff of maximum discrimination. Significantly more patients with MV < 72% of baseline during cross-clamp exhibited cognitive dysfunction than patients with MV ≥ 72% of baseline (74.1% versus 27.1%, p < 0.001). Reduced MCA-MV during cross-clamp is a predictor of cognitive dysfunction exhibited 24 hours after CEA. MCA-MV reduced to <72% of baseline, or a ≥28% reduction from baseline, is the threshold most strongly associated with increased risk of cognitive dysfunction. These observations should be considered by all clinicians that utilize intraoperative monitoring for CEA.
authors.affiliation: Department of Anesthesiology, Columbia University, 630 West 168th Street, P&S Box 46, New York, NY 10032, USA.
authors.forename: Joanna L
authors.initials: JL
authors.lastname: Mergeche
authors.affiliation: Department of Neurological Surgery, Columbia University, New York, NY, USA.
authors.forename: Samuel S
authors.initials: SS
authors.lastname: Bruce
authors.affiliation: Department of Neurological Surgery, Columbia University, New York, NY, USA; Department of Neurology, Columbia University, New York, NY, USA.
authors.forename: E
authors.initials: E
authors.lastname: Sander Connolly
authors.affiliation: Department of Anesthesiology, Columbia University, 630 West 168th Street, P&S Box 46, New York, NY 10032, USA; Department of Neurology, Columbia University, New York, NY, USA. Electronic address: ejh3@columbia.edu.
authors.forename: Eric J
authors.initials: EJ
authors.lastname: Heyer
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D019540:Area Under Curve; D001783:Blood Flow Velocity; D001921:Brain / Q000098:blood supply*; D016893:Carotid Stenosis / Q000601:surgery; D002560:Cerebrovascular Circulation / Q000502:physiology; D003072:Cognition Disorders / Q000209:etiology*; D004569:Electroencephalography; D016894:Endarterectomy, Carotid / Q000009:adverse effects*; D005260:Female; D006801:Humans; D064795:Intraoperative Neurophysiological Monitoring / Q000379:methods*; D008297:Male; D008875:Middle Aged; D020768:Middle Cerebral Artery / Q000000981:diagnostic imaging*; D012372:ROC Curve; D017585:Ultrasonography, Doppler, Transcranial
keywords: Carotid endarterectomy; Cognition; Cognitive dysfunction; Transcranial Doppler