Radiographic absence of the posterior communicating arteries and the prediction of cognitive dysfunction after carotid endarterectomy

Abstract

Object: Approximately 25% of patients exhibit cognitive dysfunction 24 hours after carotid endarterectomy (CEA). One of the purported mechanisms of early cognitive dysfunction (eCD) is hypoperfusion due to inadequate collateral circulation during cross-clamping of the carotid artery. The authors assessed whether poor collateral circulation within the circle of Willis, as determined by preoperative CT angiography (CTA) or MR angiography (MRA), could predict eCD.

Methods: Patients who underwent CEA after preoperative MRA or CTA imaging and full neuropsychometric evaluation were included in this study (n = 42); 4 patients were excluded due to intraoperative electroencephalographic changes and subsequent shunt placement. Thirty-eight patients were included in the statistical analyses. Patients were stratified according to posterior communicating artery (PCoA) status (radiographic visualization of at least 1 PCoA vs of no PCoAs). Variables with p < 0.20 in univariate analyses were included in a stepwise multivariate logistic regression model to identify predictors of eCD after CEA.

Results: Overall, 23.7% of patients exhibited eCD. In the final multivariate logistic regression model, radiographic absence of both PCoAs was the only independent predictor of eCD (OR 9.64, 95% CI 1.43-64.92, p = 0.02).

Conclusions: The absence of both PCoAs on preoperative radiographic imaging is predictive of eCD after CEA. This finding supports the evidence for an underlying ischemic etiology of eCD. Larger studies are justified to verify the findings of this study. Clinical trial registration no.: NCT00597883 ( http://www.clinicaltrials.gov ).

Keywords: BMI = body mass index; CA = carotid artery; CAS = CA stenosis; CBF = cerebral blood flow; CEA = carotid endarterectomy; CTA = CT angiography; DM = diabetes mellitus; EEG = electroencephalography; HTN = hypertension; MI = myocardial infarction; MRA = MR angiography; PCA = posterior cerebral artery; PCoA = posterior communicating artery; PVD = peripheral vascular disease; carotid endarterectomy; circle of Willis; cognitive dysfunction; computed tomography angiography; eCD = early cognitive dysfunction; magnetic resonance angiography; vascular disorders.