title: Baroreflex and cerebral autoregulation are inversely correlated.
abstract: BACKGROUND
  The relative stability of cerebral blood flow is maintained by the baroreflex and cerebral autoregulation (CA). We assessed the relationship between baroreflex sensitivity (BRS) and CA in patients with atherosclerotic carotid stenosis or occlusion.
  
  
  RESULTS
  Patients referred for assessment of atherosclerotic unilateral >50% carotid stenosis or occlusion were included. Ten healthy volunteers served as a reference group. BRS was measured using the sequence method. CA was quantified by the correlation coefficient (Mx) between slow oscillations in mean arterial blood pressure and mean cerebral blood flow velocities from transcranial Doppler. Forty-five patients (M/F: 36/9), with a median age of 68 years (IQR:17) were included. Thirty-four patients had carotid stenosis, and 11 patients had carotid occlusion (asymptomatic: 31 patients; symptomatic: 14 patients). The median degree of carotid steno-occlusive disease was 90% (IQR:18). Both CA (P=0.02) and BRS (P<0.001) were impaired in patients as compared with healthy volunteers. CA and BRS were inversely and strongly correlated with each other in patients (rho=0.58, P<0.001) and in healthy volunteers (rho=0.939; P<0.001). Increasing BRS remained strongly associated with impaired CA on multivariate analysis (P=0.004).
  
  
  CONCLUSIONS
  There was an inverse correlation between CA and BRS in healthy volunteers and in patients with carotid stenosis or occlusion. This might be due to a relative increase in sympathetic drive associated with weak baroreflex enhancing cerebral vasomotor tone and CA.
authors.affiliation: Department of Clinical Neurosciences, University of Cambridge, School of Clinical Medicine.
authors.forename: Nathalie
authors.initials: N
authors.lastname: Nasr
authors.forename: Marek
authors.initials: M
authors.lastname: Czosnyka
authors.forename: Anne
authors.initials: A
authors.lastname: Pavy-Le Traon
authors.forename: Marc-Antoine
authors.initials: MA
authors.lastname: Custaud
authors.forename: Xiuyun
authors.initials: X
authors.lastname: Liu
authors.forename: Georgios V
authors.initials: GV
authors.lastname: Varsos
authors.forename: Vincent
authors.initials: V
authors.lastname: Larrue
mesh_terms: D000328:Adult; D000368:Aged; D017704:Baroreflex; D001783:Blood Flow Velocity; D001794:Blood Pressure; D016893:Carotid Stenosis / Q000473:pathology / Q000503:physiopathology*; D002560:Cerebrovascular Circulation; D005260:Female; D006801:Humans; D002537:Intracranial Arteriosclerosis / Q000473:pathology / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies