title: Impaired dynamic cerebral autoregulation and cerebrovascular reactivity in middle cerebral artery stenosis.
abstract: OBJECTIVE
  We sought to investigate the capacity of cerebral autoregulation and cerebrovascular reactivity (CVR) in patients with middle cerebral artery (MCA) stenosis.
  
  
  METHODS
  Twenty-one patients with MCA stenosis diagnosed by magnetic resonance angiography and 15 healthy controls were enrolled. Cerebral autoregulation was assessed by autoregulatory parameters (rate of recovery/phase/gain) derived from transfer function from spontaneous oscillations of cerebral blood flow velocity and blood pressure. CVR was tested by a rebreathing maneuver.
  
  
  RESULTS
  Rate of recovery, phase and CVR estimated from moderate MCA stenosis (rate of recovery  = 17.76 ± 8.21%/s, phase  = 26.93 ± 15.67°, and CVR  = 1.53 ± 0.84%/mmHg, respectively) were significantly different (p<0.05) from controls (rate of recovery  = 39.62 ± 27.99%/s, phase  = 55.66 ± 22.10°, and CVR = 2.18 ± 0.80%/mmHg, respectively). Rate of recovery (r = -0.698, p<0.001), phase (r = -0.738, p<0.001)) and CVR (r = -0.690, p<0.001) were all significantly correlated with the degree of stenosis.
  
  
  CONCLUSIONS
  Cerebral autoregulation and CVR were impaired in patients with ≥ 50% MCA stenosis. The measures of both hemodynamic properties were inversely correlated with the stenotic degree.
authors: Department of Neurology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China.
authors: Jie
authors: J
authors: Chen
authors: Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China.
authors: Jia
authors: J
authors: Liu
authors: Department of Neurology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China.
authors: Wei-Hai
authors: WH
authors: Xu
authors: Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China.
authors: Ren
authors: R
authors: Xu
authors: Department of Radiology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China.
authors: Bo
authors: B
authors: Hou
authors: Department of Neurology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China.
authors: Li-Ying
authors: LY
authors: Cui
authors: Department of Neurology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China.
authors: Shan
authors: S
authors: Gao
mesh_terms: D001783:Blood Flow Velocity / Q000502:physiology; D001794:Blood Pressure / Q000502:physiology; D016893:Carotid Stenosis / Q000503:physiopathology*; D002540:Cerebral Cortex / Q000503:physiopathology*; D002560:Cerebrovascular Circulation / Q000502:physiology*; D005260:Female; D006439:Hemodynamics / Q000502:physiology; D006706:Homeostasis / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D020768:Middle Cerebral Artery / Q000503:physiopathology*