Changes of cerebral hemodynamics after unilateral carotid endarterectomy for severe stenotic lesions of bilateral internal carotid artery

Objective To investigate the changes of cerebral hemodynamics after unilateral carotid endarterectomy (CEA) for severe stenotic lesions of bilateral internal carotid artery (ICA). Methods The clinical data of 41 consecutive patients with ICA stenosis admitted to Department of Neurosurgery, the First Affiliated Hospital of Soochow University from February 2012 to June 2018 were retrospectively studied. All patients were diagnosed by multi-modal images based on cerebrovascular ultrasound results with severe stenotic lesions of bilateral ICA and underwent unilateral CEA. The patency of anterior communicating arteries (ACoA) and posterior communicating arteries (PCoA) were evaluated by CT angiography (CTA) before and after CEA. According to postoperative CTA revealing whether ACoA was patent or not, 41 cases were divided into ACoA patent group (15 cases) and ACoA non-patent group (26 cases). We used transcranial Doppler (TCD) and CT perfusion imaging (CTP) to evaluate these changes of cerebral hemodynamics after operation in two groups, and analyzed their clinical outcomes. Results (1) Changes of cerebral collateral circulation based on CTA images: After CEA, the opening rate of ACoA increased significantly [pre-operation: 4.9% (2/41), postoperation: 36.6% (15/41)], and all the PCoA on the operated side were closed [pre-operation: 51.2% (21/41), postoperation: 0%]. In contrast, the opening rate of PCoA remained unchanged on the non-operated side [pre-operation: 46.3% (19/41), postoperation: 46.3% (19/41)]. (2) Changes of TCD parameters: Compared with the mean velocity (Vm) and pulsatility index (PI) before surgery, those of the middle cerebral artery (MCA) on the operated side of two groups and on the non-operated side of ACoA patent group were significantly increased (all P 0.05). There was no significant difference in Vm or PI of MCA on the operated side or PI of MCA on non-operated side between two groups after operation (all P>0.05), whereas the Vm of MCA on non-operated side in the ACoA patent group was significantly higher than that in ACoA non-patent group (P 0.05). There were no significant differences in CTP parameters on the operated side between two groups after operation (all P>0.05), whereas the CTP parameters on the non-operated side in ACoA patent group were significantly improved compared with those in ACoA non-patent group (all P<0.05). (4) Clinical outcomes: The neurological function deficits of brain areas supplied by ICA on the operated side improved in both groups. As to the neurological function deficits of brain areas supplied by ICA on the non-operated side, the improvement rate in ACoA patent group was higher than that in ACoA non-patent group (7/15 vs. 5/26, P=0.024). Conclusion After unilateral CEA for severe stenotic lesions of bilateral ICA, the opening of ACoA could simultaneously improve the cerebral perfusion on the non-operated side. Key words: Carotid stenosis; Endarterectomy, carotid; Collateral circulation; Hemodynamics