Informativity of blood flow distribution in the precerebral arteries for determining the hemodynamic significance of carotid stenosis

Abstract

Introduction. Conventionally, hemodynamic significance of carotid stenosis is characterized with an increased peak systolic velocity up to 230 cm/s, which corresponds to 70 % carotid stenosis. This does not take into account changes of cerebral hemodynamics or collateral circulation, which can be determined by assessment of blood flow distribution in precerebral arteries. Aim – to evaluate blood flow redistribution in precerebral arteries in patients with critical carotid stenosis. Materials and methods. 40 patients (aged 49–80 y. o.) with critical carotid stenosis were studied (13 patients had 70–79 % stenosis, 11 patients – 80–89 %, and 16 patients – 90–99 % stenosis). Flow velocity index in precerebral arteries was determined with duplex scanning (Vivid e, USA), whereas linear blood flow velocity in intracranial arteries – with transcranial Doppler (MultiDop X, Germany). Results. In 60 % of patients, flow velocity index in ipsilateral carotid artery was reliably decreased (p<0.05). In 49 % of patients flow velocity index in contralateral carotid artery and blood flow velocity in contralateral anterior cerebral artery were reliably increased (p<0.05), as well as linear blood flow velocity in the contralateral anterior cerebral artery. Just in 39 % of patients flow velocity index in ipsilateral vertebral artery and linear blood flow velocity in ipsilateral posterior cerebral artery were increased (p<0.05). In 13 % of cases flow velocity index in the external carotid artery was increased (p<0.05). Conclusion. Thus, critical degree of carotid stenosis does not always indicate its hemodynamic significance. Flow velocity index distribution in precerebral arteries can be used as an additional criterion for assessing hemodynamic significance of carotid stenosis and, along with other indicators, should be taken into account when choosing treatment modality.