Impact of the Supra-Aortic Trunks and Circle of Willis Patency on the Neurological Compensation during Carotid Endarterectomy

Abstract

Background: One of the most critical phases of carotid endarterectomy (CEA) is the carotid cross-clamping test, which is a concrete evaluation of efficacy of collateral cerebral perfusion. Some studies revealed a strong correlation between tolerance to carotid cross-clamping and postoperative transient ischemic attack (TIA)/stroke complications. The aim of the study is to make a global analysis of supra-aortic trunks (SAT) and circle of Willis (CoW) patency to predict the tolerance to carotid cross-clamping preoperatively.

Methods: We observed retrospectively 503 patients who underwent CEA under local anesthesia between January 2012 and 2017. We analyzed single preoperative risk factors, drug therapy, and vessels patency of the group of patients who did or did not present neurological symptoms at carotid cross-clamping. Afterward, we created a cerebral perfusion score (P_TOT) to estimate the efficacy of collateral cerebral perfusion and we compared the results from both groups. The score ranges from 0 (hypothetical total occlusion of the SAT and CoW) to 0.65 in case of patency of all arterial districts. Moreover, we evaluated postoperative complication rates.

Results: Patients with previous neurological symptoms, female gender, and diabetes correlate with a lower tolerance to carotid cross-clamping (odds ratio: 2.57, 2.78, and 2.57, respectively; P value < 0.05). The SAT and CoW score revealed that patients with score <0.2 more frequently did not tolerate carotid cross-clamping (P value 0.01). Patients who required an intraoperative shunt presented a higher risk of TIA/stroke within 30 days from surgery than those with a better neurological compensation (P value 0.03).

Conclusions: The efficacy of cerebral mechanisms of compensation during carotid cross-clamping reflects the capability of the brain to adapt to ischemic insults, and this also correlates with the postoperative risk of TIA/stroke. It is possible to identify preoperatively patients with a higher risk of neurological intolerance at carotid cross-clamping. This score could be a useful method to make a further stratification of risk of neurological complications and eventually to prefer a general anesthesia and the use of shunt for those with P_TOT < 0.2.