Long-term outcomes of carotid endarterectomy with eversion technique in patients with an open circle of Willis: A multicenter registry study.

Introduction: Carotid endarterectomy (CEA) is a surgery aimed at removing atherosclerotic plaque from the carotid artery. There are classical and eversion CEA techniques. The eversion technique is the most popular because it does not require the use of implants. Eversion CEA is also associated with a lower risk of restenosis in the late postoperative period. During the surgery, the carotid artery is clamped and blood flow to the brain comes from the contralateral carotid artery and vertebral arteries. However, if the circle of Willis (COW) is not closed, compensatory mechanisms for protecting the brain are reduced, which can lead to the development of an intraoperative stroke.

Purpose: To analysis of in-hospital and long-term CEA outcomes in patients with different types of closed and non-closed COW.

Methods: This is a multicenter Russian study. In the period from 2010 to 2020. 641 eversion CEA were performed. Depending on the type of structure of the COW, six groups of patients were formed: Type 1 - Closed posterior part (CRS) - in the presence of the posterior communicating (PCOMA) and P1 segment of the posterior cerebral (PCA) arteries; Type 2 - Intermediate type of structure of the posterior part (ISRP) - with hypoplasia of PCOMA or PCA; Type 3 - Open back part (OBP) - in the absence of PCOMA or PCA; Type 4 - Closed anterior part (CFS) - in the presence of the anterior communicating artery (ACOMA) and the A1 segment of the anterior cerebral artery (ACA); Type 5 - Intermediate type of anterior part structure (IFPS) - with ACOMA or ACA hypoplasia; Type 6 - Open Front Section (OFS) - in the absence of ACOMA or ACA. The long-term follow-up period was 107.3 ± 14.6 months. The end points of the study were death, ischemic stroke, transient ischemic attack (TIA), myocardial infarction (MI), ICA thrombosis, hemodynamically significant restenosis of the internal carotid artery, bleeding, and combined endpoint (death + ischemic stroke + TIA + MI).The type of distribution was determined using the Kolmogorov-Smirnov criterion. Group comparisons were performed using the Kruskal-Wallis and Pearson chi-square tests. Differences were assessed as significant at < .05. According to clinical and demographic characteristics, the majority of patients were male and elderly. In 20% of cases, patients had a history of MI and/or stroke/TIA. Diabetes mellitus was diagnosed in 10%. There were no significant differences between groups in EuroSCOREII.

Results: In the long-term postoperative period, the largest number of deaths occurred in groups 5 and 6 (13 (45.1%) and 12 (30.1%)). The majority of strokes were diagnosed in groups 3 (OBP) and 5 (IFPS) (7 (13.5%) and 9 (17.6%)). The highest value of the combined end point (death + stroke/TIA + MI) was obtained in groups 3 (OBP), 5 (IFPS), and 6 (OFS) (23 (44.2%), 26 (50.1%), and 23 (58.9%)).

Conclusion: The eversion technique of carotid endarterectomy for carotid artery stenosis is the most preferred. The greatest number of complications of eversion CEA in the hospital and long-term follow-up periods is observed in patients with OBP, IFPS, and OFS. In the presence of an unstable plaque, a temporary shunt can be used, which will exclude the pharmacological increase in blood pressure and the associated risk of embolization.