title: The carotid artery as an alternative site for dynamic autoregulation measurement: an inter-observer reproducibility study.
abstract: The internal carotid artery (ICA) has been proposed as an alternative site to the middle cerebral artery (MCA) to measure dynamic cerebral autoregulation (dCA) using transcranial Doppler ultrasound (TCD). Our aim was to test the inter-operator reproducibility of dCA assessment in the ICA and the effect of interaction amongst different variables (artery source × operator × intra-subject variability). Two operators measured blood flow velocity using TCD at the ICA and MCA simultaneously on each side in 12 healthy volunteers. The autoregulation index (ARI) was estimated by transfer function analysis. A two-way repeated measurements ANOVA with post-hoc Tukey tested the difference between ARI by different operators and interaction effects were analysed based on the generalized linear model. In this healthy population, no significant differences between operator and no interaction effects were identified amongst the different variables. This study reinforced the validity of using the ICA as an alternative site for the assessment of dCA. Further work is needed to confirm and extend our findings, particularly to disease populations.
authors.affiliation: Department of Neurology, Hospital das Clinicas, University of São Paulo School of Medicine, São Paulo, Brazil. Electronic address: rcnogueira28@gmail.com.
authors.forename: R C
authors.initials: RC
authors.lastname: Nogueira
authors.affiliation: Department of Cardiovascular Sciences, University of Leicester, Leicester LE2 7LX, UK.
authors.forename: N P
authors.initials: NP
authors.lastname: Saeed
authors.affiliation: Department of Neurosurgery, Hospital das Clinicas, University of São Paulo School of Medicine, São Paulo, Brazil.
authors.forename: E
authors.initials: E
authors.lastname: Bor-Seng-Shu
authors.affiliation: Department of Neurosurgery, Hospital das Clinicas, University of São Paulo School of Medicine, São Paulo, Brazil.
authors.forename: M J
authors.initials: MJ
authors.lastname: Teixeira
authors.affiliation: Department of Cardiovascular Sciences, University of Leicester, Leicester LE2 7LX, UK; NIHR Biomedical Research Unit in Cardiovascular Science, Glenfield Hospital, Leicester LE3 9QP, UK.
authors.forename: T G
authors.initials: TG
authors.lastname: Robinson
authors.affiliation: Department of Cardiovascular Sciences, University of Leicester, Leicester LE2 7LX, UK; NIHR Biomedical Research Unit in Cardiovascular Science, Glenfield Hospital, Leicester LE3 9QP, UK.
authors.forename: R B
authors.initials: RB
authors.lastname: Panerai
mesh_terms: D000328:Adult; D000368:Aged; D000704:Analysis of Variance; D001921:Brain / Q000098:blood supply* / Q000378:metabolism*; D002339:Carotid Arteries / Q000000981:diagnostic imaging* / Q000378:metabolism*; D005260:Female; D006706:Homeostasis; D006801:Humans; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D017585:Ultrasonography, Doppler, Transcranial
keywords: Dynamic cerebral autoregulation; Internal carotid artery; Measurement reproducibility; Middle cerebral artery; Transcranial Doppler ultrasound