Stroke patients with carotid disease have a high risk of recurrence of disease. By measuring
cerebral blood flow volume (BFV) using extracranial duplex technique for clinical estimation of
intracranial collaterals, we aimed to investigate the relationship between the presence of intracranial
collaterals and stroke recurrence in stroke patients with carotid disease. Consecutive stroke patients
indicated for carotid duplex ultrasound investigations in our hospital were recruited during three
years’ period. Carotid stenosis was diagnosed as ≥50% stenosis and extracranial arterial BFV was
measured by using color velocity imaging quantification ultrasound (CVIQ) software. Presence of
intracranial collateral flow was defined as a blood flow volume of either 370 mL/min in common
carotid artery or ≥120 mL/min in vertebral artery. Univariate and multivariate analyses were performed
to determine the independent predictors of recurrent stroke. One hundred and twelve stroke
patients (19.1%) with 50% carotid stenosis were recruited from consecutive ischemic stroke patients.
During a mean follow-up of 28.6±13.1 months, recurrent stroke was recorded in 32 (28.6%)
out of the total recruited patients. Estimated by blood flow volume measured by CVIQ, the patients
with intracranial collateral flow had a lower rate of recurrent stroke than those without (9.5% vs.
33%, P=0.032). After adjusting for potential confounders, the presence of CVIQ-estimated intracranial
collateral flow was an independent protector of recurrent stroke (OR, 0.169; 95% CI, 0.034-
0.842; P=0.03). It could be concluded that blood supply through intracranial collateral flow estimated
by CVIQ technique may protect stroke patients with carotid stenosis from suffering recurrent stroke.
Keywords: Collateral circulation, carotid stenosis, stroke, ultrasonography, BFV.
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