Introduction: Whereas large studies identified that contralateral carotid occlusion (CCO) has higher perioperative stroke risk in patients who underwent carotid endarterectomy (CEA), single-center studies have not confirmed this. Circle of Willis (CoW) is considered an important collateral network to maintain blood flow during cross-clamping in carotid endarterectomy (CEA). The aim of this study was to evaluate the impact of the CCO in association with CoW on immediate neurological event (INE) after CEA without shunt protection. Methods: We reviewed the clinical data and outcomes of 114 patients (80 males mean age 65.9±8.7 years) who underwent CEA with CCO under general anesthesia between 01.01.2013 and 30.06.2018. Patients who had CEA with shunt (46) and with inadequate intracranial imaging (16) were excluded. Indications were asymptomatic (75%) and symptomatic (25%) carotid artery disease. CTAs were reviewed independently by two vascular radiologists who were blinded for treatment outcomes. Imaging assessment included the vertebral and carotid circulation and each segment of the CoW. Segments were classified as normal, hypoplastic (diameter ˂ 1mm) or absent. CoW was assessed for short semicircle (ipsilateral P1 and Pcom) and long (from the contralateral P1 to the ipsiA1) semicircles considered as sufficient if there were normal segments between the basilar and the ipsilateral middle cerebral artery (MCA). INE was defined as any transient ischemic attack (TIA) and stroke diagnosed immediately after the procedure. Results: Of the 52 included patients only two had a stroke (3.8%) in the postoperative period. From the two strokes one was immediate after the surgery. In addition of this stroke there were 3 immediate TIAs giving the 4 (7.7%) INE. Only one third of this study population (n=18; 34%) had normal, 17 patients (33%) had at least one hypoplastic segments and other 17 (33%) had missing segments between the clamped carotid and the basilar artery - short semicircle. There was no neurologic event with normal short semicircle. From the 4 INE two patients had hypoplastic and two had absent short semicircle. In all INE cases the other, long semicircle was insufficient as well. Conclusion: Contralateral carotid occlusion carries insignificant risk of INE or stroke after CEA with cross-clamping without shunt protection, when CoW collateral flow support is sufficient. In patients with CCO shunting is recommended when the collateral flow between the ipsilateral MCA and the basilar artery is compromised. Disclosure: Nothing to disclose
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