Cerebral Autoregulation Monitoring During Cardiac Surgery

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Know the risks and potential benefits of clinical studies and talk to your health care provider before participating. Read our disclaimer for details. Identifier: NCT00981474
Recruitment Status : Recruiting
First Posted : September 22, 2009
Last Update Posted : March 30, 2018
National Heart, Lung, and Blood Institute (NHLBI)
Information provided by (Responsible Party):
Charles W Hogue, Northwestern University

Brief Summary:
Neurological complications from cardiac surgery are an important source of operative mortality, prolonged hospitalization, health care expenditure, and impaired quality of life. New strategies of care are needed to avoid rising complications for the growing number of aged patients undergoing cardiac surgery. This study will evaluate novel methods for reducing brain injury during surgery from inadequate brain blood flow using techniques that could be widely employed.

Condition or disease Intervention/treatment Phase
Thoracic Surgery Cardiopulmonary Bypass Drug: blood pressure maintenance based on cerebral blood flow autoregulation measurement Drug: Control group Not Applicable

Detailed Description:
Brain injury during cardiac surgery results primarily from cerebral embolism and/or reduced cerebral blood flow (CBF). The latter is of particular concern for the growing number of surgical patients who are aged and/or who have cerebral vascular disease. Normally, CBF is physiologically autoregulated (or kept constant) within a range of blood pressures allowing for stable cerebral O2 supply commensurate with metabolic demands. Cerebral autoregulation is impaired in patients undergoing cardiac surgery who have cerebral vascular disease and in many others due to other conditions. This could lead to brain injury since current practices of targeting low mean arterial blood pressure empirically (usually 50-70 mmHg) during cardiopulmonary bypass may expose patients with impaired cerebral autoregulation to cerebral hypoperfusion. The hypothesis of this proposal is that targeting mean arterial pressure during cardiopulmonary bypass to a level above an individual's lower autoregulatory threshold reduces the risk for brain injury in patients undergoing cardiac surgery. Monitoring of cerebral autoregulation will be performed in real time using software that continuously compares the relation between arterial blood pressure and CBF velocity of the middle cerebral artery measured with transcranial Doppler and with cerebral oximetry measured with near infrared spectroscopy. The primary end-point of the study will be a comprehensive composite outcome of clinical stroke, cognitive decline, and/or new ischemic brain lesions detected with diffusion weighted magnetic resonance (MR) imaging. Delirium assessed using a validated procedure that includes validated tools is a secondary outcome measure. Autoregulation is mediated by reactivity of cerebral resistance vessels. A secondary aim of this proposal is to evaluate whether near infrared reflectance spectroscopy can be used to trend changes in cerebral blood volume and provide a reliable monitor of vascular reactivity (the hemoglobin volume index). Assessments for extra-cranial and intra-cranial arterial stenosis will be performed using MR angiography to control for this potential confounding variable in the analysis. Finally, an additional aim of the study will be to assess whether preoperative transcranial Doppler examination of major cerebral arteries can identify patients who are prone to the composite neurological end-point. Near infrared oximetry is non-invasive, continuous, requires little care-giver intervention and, thus, could be widely used to individualize patient blood pressure management during surgery. Brain injury from cardiac surgery is an important source of operative mortality, prolonged hospitalization, increased health care expenditure, and impaired quality of life. Developing strategies to reduce the burden of this complication has wide public health implications.

Study Type : Interventional  (Clinical Trial)
Estimated Enrollment : 490 participants
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Double (Participant, Outcomes Assessor)
Primary Purpose: Prevention
Official Title: Continuous Cerebral Autoregulation Monitoring to Reduce Brain Injury From Cardiac Surgery
Actual Study Start Date : September 1, 2009
Estimated Primary Completion Date : June 1, 2019
Estimated Study Completion Date : August 31, 2019

Resource links provided by the National Library of Medicine

MedlinePlus related topics: Heart Surgery

Arm Intervention/treatment
Active Comparator: Control
Blood pressure targets during cardiopulmonary bypass based on institutional standards of empiric management.
Drug: Control group
Institutional standard of care.

Experimental: Intervention
Blood pressure management based on cerebral autoregulation data.
Drug: blood pressure maintenance based on cerebral blood flow autoregulation measurement
Blood pressure lowered or raised

Primary Outcome Measures :
  1. Composite neurological outcome of clinical stroke or new ischemic brain lesion on diffusion weighted MRI or neurocognitive dysfunction 4 to 6 weeks after surgery. [ Time Frame: Perioperative ]

Secondary Outcome Measures :
  1. Postoperative Delirium [ Time Frame: Postoperative days 1-3 ]
    Assessed with Confusion Assessment Method or Confusion Assessment Method-ICU along with adjudication by team of experts

Information from the National Library of Medicine

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Ages Eligible for Study:   60 Years and older   (Adult, Older Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   No

Inclusion Criteria:

  • Male or female patients undergoing primary or re-operative CABG and/or valvular surgery that requires CPB who are at high risk for neurologic complications (stroke or encephalopathy) as determined by a Johns Hopkins risk score of >0.1

Exclusion Criteria:

  • Contraindication to MRI imaging (e.g., permanent pacemaker, cerebral arterial vascular clips)
  • Liver function test before surgery more than twice the upper limit of institutional normal
  • Pre-existing renal dysfunction defined as an estimated glomerular filtration rate of ≤60 mL/min, or current renal dialysis
  • Emergency surgery
  • Inability to attend outpatient visits
  • Visual impairment or inability to speak and read English. The patient will be excluded from further study if an adequate temporal window for TCD monitoring can not be identified before surgery.

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its identifier (NCT number): NCT00981474

Contact: Charles W Hogue, MD 3129262949

United States, Illinois
Northwestern Memorial Hospital Recruiting
Chicago, Illinois, United States, 60611
Contact: Paul Fitzgerral, BSN    312-926-2949   
Principal Investigator: Charles W. Hogue, MD         
Sponsors and Collaborators
Northwestern University
National Heart, Lung, and Blood Institute (NHLBI)

Publications automatically indexed to this study by Identifier (NCT Number):
Responsible Party: Charles W Hogue, Professor, Northwestern University Identifier: NCT00981474     History of Changes
Other Study ID Numbers: 680
1R01HL092259 ( U.S. NIH Grant/Contract )
First Posted: September 22, 2009    Key Record Dates
Last Update Posted: March 30, 2018
Last Verified: March 2018
Individual Participant Data (IPD) Sharing Statement:
Plan to Share IPD: No

Studies a U.S. FDA-regulated Drug Product: No
Studies a U.S. FDA-regulated Device Product: No
Product Manufactured in and Exported from the U.S.: No

Keywords provided by Charles W Hogue, Northwestern University:
cardiac surgery; brain injury; cerebral autoregulation