Independent role of circle of Willis for peri-procedural evaluation of carotid endarterectomy in patients with severe carotid stenosis

Abstract

Objectives: In patients with severe carotid stenosis (CS), collateral circulation via circle of Willis (CoW) is considered a compensatory response to maintain blood flow. The aim of this study was to evaluate the impact of CoW in patients with severe CS throughout carotid endarterectomy (CEA).

Methods: A database of patients (n = 124) undergoing CEA was sampled from 2013 to 2020. Severe CS was defined as 90-99% caliber stenosis and collateral circulation was identified by CoW opening. Baseline characteristics, Age-related white matter change (ARWMC) score, immediate neurologic events (INEs) and manifestations were recorded and compared. Correlation and regression analysis for CoW were further investigated.

Results: All patients enrolled were divided into two groups regarding to the visualized CoW opening and complete CoW was noticed in 57 patients. The prevalence of complete CoW was higher among asymptomatic patients (n = 39, 68.4%), while higher percentage of TIA or previous stroke were noticed in incomplete CoW (n = 45, 67.2%). Patients with incomplete CoW had a significantly higher median ARWMC score and remarkable cerebral perfusion deficit (P < 0.05*). Totally, 4 INEs (6.0%) were noted in patients with incomplete CoW after CEA. Cerebral hyperperfusion syndrome (CHS) was noticed in 10 patients and early-phase of postoperative hypertension (EPOH) in 15 ones with incomplete CoW versus patients with complete CoW (14.9% and 22.4% vs 3.5% and 7.0%, P < 0.05). Correlation analysis showed strong relationship between CoW opening and peri-operative factors like pre-operative symptoms, ARWMC, CHS and EPOH (P < 0.05*). Overall, CoW opening was an independent predictor of both CHS and EPOH (95% CI, 0.021-0.715 and 0.060-0.949, P < 0.05*) with logistic regression.

Conclusions: Sufficient collateral circulation via CoW may promote ipsilateral cerebral perfusion and mitigate WMC in patients with severe CS. In addition, collaterals may improve the predictive power of the risk scale for post-procedural complications after CEA.

Keywords: Carotid endarterectomy; Circle of Willis; Immediate neurologic events; Severe carotid stenosis; White matter changes.