Neuroinflammation and Postoperative Delirium in Cardiac Surgery

Up to 50% of patients over 60 years old develop postoperative delirium following cardiac surgery. Delirium increases morbidity and mortality, and may lead to long-term cognitive impairment similar to patients with a diagnosis of Alzheimer's disease. The underlying mechanisms behind delirium are not understood, and therefore the current prevention and treatment strategies are inadequate. Several hypotheses exist for the pathophysiology of delirium, one of which is the role of neuroinflammation. The stress associated with high-risk procedures such as cardiac surgery may lead to systemic inflammation causing endothelial dysfunction and disruption of the blood brain barrier (BBB). When this occurs, the brain is susceptible to neuronal injury via neuroinflammation after which a state of delirium may ensue. To characterize the mechanisms of neuroinflammation in delirium, the investigators will explore the biomarkers most closely linked to each step of the proposed pathway.

Study Overview

• Status: Completed
• Conditions: Delirium; Cardiac Surgery

Detailed Description

Aim 1a. Test the hypothesis that endothelial injury is associated with delirium. The investigators hypothesize that endothelial dysfunction is associated with an increased incidence of delirium after cardiac surgery. To test this hypothesis, the investigators will measure biomarkers from subjects undergoing cardiac surgery. Blood samples from three time points [baseline, upon arrival to the intensive care unit (ICU), and postoperative day 1 (POD1)] will be analyzed and compared between patients that did and did not develop postoperative delirium.

Aim 1b. Test the hypothesis that BBB disruption is associated with delirium. The investigators hypothesize that disruption in the BBB is associated with an increased incidence of delirium after cardiac surgery. To test this hypothesis, the investigators will measure levels of biomarkers at baseline, upon arrival to the ICU, and on POD1.

Aim 1c. Test the hypothesis that neuronal injury is associated with delirium. The investigators hypothesize that neuronal injury is associated with an increased incidence of delirium after cardiac surgery. To test this hypothesis, the investigators will measure levels of biomarkers at baseline, upon arrival to the ICU, and on POD1.

• Study Type: Observational
• Enrollment (Actual): 630

Contacts and Locations

Study Locations

• United States
  • Tennessee
    • Nashville, Tennessee, United States, 37232
      • Vanderbilt University Medical Center

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years and older (Adult, Older Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

• Sampling Method: Non-Probability Sample

Study Population

Patients over the age of 18 undergoing open heart surgery

Description

Inclusion Criteria:

• open heart surgery

Exclusion Criteria:

• acute coronary syndrome with troponin leak or unrelenting angina
• liver dysfunction (transaminases 2x normal)
• history of myopathy or liver dysfunction on prior statin therapy
• use of potent CYP3A4 inhibitors such as antifungal azoles, macrolide antibiotics, HIV protease inhibitors, and nefazodone.
• pregnancy or breast feeding
• cyclosporine use
• dialysis
• history of kidney transplant
• fibrate users who cannot stop fibrate use

Study Plan

How is the study designed?

Design Details

• Observational Models: Cohort
• Time Perspectives: Prospective

Number of groups / cohorts

1

Cohorts and Interventions

Group / Cohort
Cardiac surgery patients

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
change in endothelial dysfunction	biomarker of endothelial dysfunction to be measured at 3 time points	baseline, postoperative day 0, postoperative day 1
change in blood brain barrier disruption	biomarker of blood brain barrier disruption to be measured at 3 time points	baseline, postoperative day 0, postoperative day 1
change in neuronal injury	biomarker of neuronal injury to be measured at 3 time points	baseline, postoperative day 0, postoperative day 1

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
delirium as screened with CAM-ICU	CAM-ICU measured twice daily by research assistant to screen for delirium	twice daily after surgery until discharge from ICU (12 hours, 24 hours, 36 hours, 48 hours, 60 hours, 72 hours, 84 hours, 96 hours, continuing every 12 hours up to 24 weeks)

Collaborators and Investigators

• Sponsor: Vanderbilt University

Study record dates

Study Major Dates

• Study Start (Actual): January 1, 2016
• Primary Completion (Actual): March 1, 2017
• Study Completion (Actual): March 1, 2017

Study Registration Dates

• First Submitted: February 5, 2016
• First Submitted That Met QC Criteria: February 22, 2016
• First Posted (Estimate): February 23, 2016

Study Record Updates

• Last Update Posted (Actual): September 17, 2018
• Last Update Submitted That Met QC Criteria: September 13, 2018
• Last Verified: September 1, 2018

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Mental Disorders; Nervous System Diseases; Neurologic Manifestations; Confusion; Neurobehavioral Manifestations; Neurocognitive Disorders; Delirium
• Other Study ID Numbers: 160032

Drug and device information, study documents

• 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