title: Cerebral blood flow autoregulation is preserved after continuous-flow left ventricular assist device implantation.
abstract: OBJECTIVE
  To compare cerebral blood flow (CBF) autoregulation in patients undergoing continuous-flow left ventricular assist device (LVAD) implantation with that in patients undergoing coronary artery bypass grafting (CABG).
  
  
  METHODS
  Prospective, observational, controlled study.
  
  
  METHODS
  Academic medical center.
  
  
  METHODS
  Fifteen patients undergoing LVAD insertion and 10 patients undergoing CABG.
  
  
  RESULTS
  Cerebral autoregulation was monitored with transcranial Doppler and near-infrared spectroscopy. A continuous Pearson correlation coefficient was calculated between mean arterial pressure (MAP) and CBF velocity and between MAP and near-infrared spectroscopic data, rendering the variables mean velocity index (Mx) and cerebral oximetry index (COx), respectively. Mx and COx approach 0 when autoregulation is intact (no correlation between CBF and MAP), but approach 1 when autoregulation is impaired. Mx was lower during and immediately after cardiopulmonary bypass in the LVAD group than in the CABG group, indicating better-preserved autoregulation. Based on COx monitoring, autoregulation tended to be better preserved in the LVAD group than in the CABG group immediately after surgery (p = 0.0906). On postoperative day 1, COx was lower in the LVAD group than in the CABG group, indicating preserved CBF autoregulation (p = 0.0410). Based on COx monitoring, 3 patients (30%) in the CABG group had abnormal autoregulation (COx ≥0.3) on the first postoperative day but no patient in the LVAD group had this abnormality (p = 0.037).
  
  
  CONCLUSIONS
  These data suggest that CBF autoregulation is preserved during and immediately after surgery in patients undergoing LVAD insertion.
authors.affiliation: Department of Surgery, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
authors.forename: Masahiro
authors.initials: M
authors.lastname: Ono
authors.forename: Brijen
authors.initials: B
authors.lastname: Joshi
authors.forename: Kenneth
authors.initials: K
authors.lastname: Brady
authors.forename: R Blaine
authors.initials: RB
authors.lastname: Easley
authors.forename: Kathy
authors.initials: K
authors.lastname: Kibler
authors.forename: John
authors.initials: J
authors.lastname: Conte
authors.forename: Ashish
authors.initials: A
authors.lastname: Shah
authors.forename: Stuart D
authors.initials: SD
authors.lastname: Russell
authors.forename: Charles W
authors.initials: CW
authors.lastname: Hogue
mesh_terms: D000368:Aged; D001794:Blood Pressure / Q000502:physiology; D002560:Cerebrovascular Circulation / Q000502:physiology*; D001026:Coronary Artery Bypass / Q000639:trends; D005260:Female; D006353:Heart-Assist Devices / Q000639:trends; D006706:Homeostasis / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010865:Pilot Projects; D011446:Prospective Studies