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Issue: Issue 1 (2014) – Supplement 1


Original Article

Internal carotid artery stenosis: validation of Doppler velocimetric criteria

Author(s):
Ana Monteiro, Rosa Santos, Carmen Ferreira, Andreia Costa, and Elsa Azevedo
Abstract:
Background: Carotid endarterectomy is effective in reducing recurrent stroke in patients with carotid stenosis. Duplex sonography is widely used for diagnosing internal carotid artery (ICA) stenosis. Surgeons often base management decisions solely on this technique. Published velocimetric criteria should be validated in each laboratory. This study aims to validate Doppler velocimetric criteria for different grades of ICA stenosis and evaluate intracranial collateralization circuits.

Methods: Duplex scans from 10,435 consecutive patients routinely referred to our Neurosonology Unit from 2003 to 2011 were reviewed. Cases with ICA stenosis ?50% (ultrasonographic morphologic criteria) were grouped by percentage of stenosis (ECST method). Mean ICA peak-systolic (PSV) and end-diastolic velocities (EDV), carotid index and presence of collateral flow were recorded. Pearson’s coefficient was used to correlate percentage of stenosis and velocity parameters. One-way ANOVA was performed for the presence of collateralization.

Results: Nine-hundred and sixty cases of ICA stenosis ?50% were identified. The Pearson’s correlation values were R=0.802, p<0.001; R=0.724, p<0.001 and R=0.769, p<0.001 for the PSV, EDV and carotid index, respectively. The presence of collateral flow increased significantly for a stenosis ?70% (p<0.001). For stenosis ?70%, PSV >182 cm/s showed a sensibility of 80%, specificity of 82% and accuracy of 88%, EDV >61 cm/s showed a sensibility of 76%, specificity of 80% and accuracy of 86%, and carotid index >2.3 showed a sensibility of 82%, specificity of 82% and accuracy of 89%. These velocities were superior to the recently published consensus criteria for diagnosing stenosis ?70%. Collateral blood flow increased significantly for stenosis ?70% (p<0.001).

Conclusion: This work defined optimal velocimetric criteria for ICA stenosis in our laboratory, enabling the correct diagnosis when morphological criteria are lacking. The presence of collateralization was important to identify hemodinamically significant stenosis.

Keywords: Internal carotid artery stenosis, Velocimetric criteria, ECST, NASCET; Endarterectomy, Collateral blood flow.

International Journal of Clinical Neurosciences and Mental Health 2014; 1(Suppl. 1):S13

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