Compensatory patterns of collateral flow in stroke patients with unilateral and bilateral carotid stenosis
Hui Fang1,2, Bo Song1, Bo Cheng2
1Department of Neurology, the First Affiliated Hospital of Zhengzhou University, No.1 Jianshe East Road, Erqi District, Zhengzhou, Henan, PR China.
Insights
In acute stroke patients, unilateral carotid stenosis increases blood flow in the opposite carotid artery. Bilateral stenosis leads to increased vertebral artery blood flow, indicating compensatory mechanisms for cerebral perfusion.
Area of Science:
- Neurology
- Vascular Medicine
- Medical Imaging
Background:
- Collateral pathways are crucial for maintaining cerebral blood flow in patients with carotid stenosis.
- Understanding hemodynamic compensation is vital for managing acute stroke patients.
Purpose of the Study:
- To investigate hemodynamic patterns in relation to internal carotid artery (ICA) stenosis in acute stroke patients.
- To quantify blood flow volume (BFV) changes in response to varying degrees of carotid stenosis.
Main Methods:
- A cohort of 586 acute stroke patients was analyzed.
- Carotid duplex identified internal carotid artery stenosis (≥50% diameter reduction).
- Color velocity imaging quantification ultrasound (CVIQ) measured blood flow volume in common carotid arteries (CCAs) and vertebral arteries (VAs).
Main Results:
- 19.1% of patients had ICA stenosis (13.8% unilateral, 5.3% bilateral).
- Unilateral stenosis showed significantly higher contralateral CCA blood flow (325.5 mL/min vs. 242.2 mL/min).
- Bilateral stenosis demonstrated increased vertebral artery blood flow (22% of cerebral blood flow) compared to no stenosis (14.8%) or unilateral stenosis (16.9%).
Conclusions:
- Contralateral carotid artery blood flow compensates for reduced flow in unilateral internal carotid artery stenosis.
- Posterior circulation, via vertebral arteries, compensates for decreased brain perfusion in bilateral internal carotid artery stenosis.
Background:
Collateral pathways are important in maintaining adequate cerebral blood flow in patients with carotid stenosis. We aimed to evaluate the hemodynamic patterns in relation to carotid stenosis in acute stroke patients.
Methods:
Consecutive 586 stroke patients in a hospital based cohort were included in the present study. Carotid duplex was performed to identify patients with absolute minimal diameter reductions of 50% or greater in their internal carotid arteries (ICAs). Color velocity imaging quantification ultrasound (CVIQ) was used to measure extracranial arterial blood flow volume (BFV) in bilateral common carotid arteries (CCAs) and bilateral vertebral arteries (VAs). The absolute values of BFV and the ratios were compared between patients with and without ICA stenosis.
Results:
Among 586 acute ischemic stroke patients (mean age: 67.5 ± 12.4y), ICA stenosis was detected in 112 patients (19.1%), including unilateral ICA stenosis in 81 patients (13.8%) and bilateral ICA stenosis in 31 patients (5.3%). Among patients with unilateral ICA stenosis, the BFV in contralateral CCA was significantly higher than that in ipsilateral CCA (325.5 ± 99.8 mL/min vs. 242.2 ± 112.2 mL/min, P < 0.001). Among patients with bilateral ICA stenosis, the sum of BFV in bilateral VAs accounted for 22% of the whole cerebral blood flow, which was significantly higher than that in those without ICA stenosis (14.8%, P < 0.001) or with unilateral ICA stenosis (16.9%, P = 0.007).
Conclusions:
In patients with unilateral carotid stenosis, contralateral carotid blood flow increases to compensate decreased blood flow, while posterior circulation may compensate for the decreased brain perfusion in those with bilateral carotid stenosis.
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