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Updated: May 17, 2026
Evaluation of Cerebral Blood Flow Autoregulation in the Rat Using Laser Doppler Flowmetry
Published on: January 19, 2020
Cerebral blood flow autoregulation is preserved after continuous-flow left ventricular assist device implantation
Masahiro Ono1, Brijen Joshi, Kenneth Brady
1Department of Surgery, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
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).
Design:
Prospective, observational, controlled study.
Setting:
Academic medical center.
Participants:
Fifteen patients undergoing LVAD insertion and 10 patients undergoing CABG.
Measurements And Main 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.
