title: Efficacy of Cerebral Autoregulation in Early Ischemic Stroke Predicts Smaller Infarcts and Better Outcome.
abstract: OBJECTIVE
  Effective cerebral autoregulation (CA) may protect the vulnerable ischemic penumbra from blood pressure fluctuations and minimize neurological injury. We aimed to measure dynamic CA within 6 h of ischemic stroke (IS) symptoms onset and to evaluate the relationship between CA, stroke volume, and neurological outcome.
  
  
  METHODS
  We enrolled 30 patients with acute middle cerebral artery IS. Within 6 h of IS, we measured for 10 min arterial blood pressure (Finometer), cerebral blood flow velocity (transcranial Doppler), and end-tidal-CO2. Transfer function analysis (coherence, phase, and gain) assessed dynamic CA, and receiver-operating curves calculated relevant cut-off values. National Institute of Health Stroke Scale was measured at baseline. Computed tomography at 24 h evaluated infarct volume. Modified Rankin Scale (MRS) at 3 months evaluated the outcome.
  
  
  RESULTS
  The odds of being independent at 3 months (MRS 0-2) was 14-fold higher when 6 h CA was intact (Phase > 37°) (adjusted OR = 14.0 (IC 95% 1.7-74.0),p= 0.013). Similarly, infarct volume was significantly smaller with intact CA [median (range) 1.1 (0.2-7.0) vs 13.1 (1.3-110.5) ml,p= 0.002].
  
  
  CONCLUSIONS
  In this pilot study, early effective CA was associated with better neurological outcome in patients with IS. Dynamic CA may carry significant prognostic implications.
authors.affiliation: Department of Neurology, São João Hospital Center, Faculty of Medicine, University of Porto , Porto , Portugal.
authors.forename: Pedro
authors.initials: P
authors.lastname: Castro
authors.affiliation: Department of Pharmacology, Physiology and Neuroscience, Rutgers Biomedical Health Sciences, Newark, NJ, USA; Department of Veteran Affairs, Veterans Biomedical Institute, War Related Illness and Injury Study Center, East Orange, NJ, USA; Cardiovascular Electronics, National University of Ireland Galway, Galway, Ireland.
authors.forename: Jorge Manuel
authors.initials: JM
authors.lastname: Serrador
authors.affiliation: Faculty of Medicine, Cardiovascular Centre, Institute of Physiology, University of Lisbon , Lisbon , Portugal.
authors.forename: Isabel
authors.initials: I
authors.lastname: Rocha
authors.affiliation: Department of Neurology, Division of Stroke and Neurocritical Care, Northwestern University Feinberg School of Medicine , Chicago, IL , USA.
authors.forename: Farzaneh
authors.initials: F
authors.lastname: Sorond
authors.affiliation: Department of Neurology, São João Hospital Center, Faculty of Medicine, University of Porto , Porto , Portugal.
authors.forename: Elsa
authors.initials: E
authors.lastname: Azevedo
keywords: blood pressure; cerebral autoregulation; ischemic stroke; stroke; transcranial Doppler