This study will examine the hypothesis that changes in the cognition (i.e. thinking and memory) after anesthesia and surgery are correlated with changes in markers of Alzheimers Disease in the fluid around the brain and spinal cord (i.e. cerebrospinal fluid, or CSF), and/or changes in brain connectivity. The investigators will also examine whether different types of anesthesia have different effects on these CSF markers of Alzheimers disease, or different effects on thinking and memory after anesthesia and surgery, or differential effects on the correlation between cognitive changes and CSF marker changes.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
DIAGNOSTIC
Masking
DOUBLE
Enrollment
191
Duke University Medical Center
Durham, North Carolina, United States
Correlation Between Perioperative Change in Cerebrospinal Fluid (CSF) Markers of Alzheimers Disease and Perioperative Cognitive Change
Spearman correlation was used here as the CSF markers follow a skewed distribution. Spearman correlation describes the strength of the monotonic relationship between two measures and is bounded between -1 and 1. Negative values indicate an inverse relationship while positive values mean that the variables move in tandem.
Time frame: Baseline to 6 weeks
Correlation Between Perioperative Change in Ratios of Cerebrospinal Fluid (CSF) Markers of Alzheimers Disease and Perioperative Cognitive Change
Spearman correlation was used here as the ratio of CSF markers follow a skewed distribution. Spearman correlation describes the strength of the monotonic relationship between two measures and is bounded between -1 and 1. Negative values indicate an inverse relationship while positive values mean that the variables move in tandem.
Time frame: Baseline to 6 weeks
Continuous Cognitive Index Score Change Difference Between Anesthetic Agent Groups
To characterize cognitive function over time, while minimizing potential redundancy in the cognitive measures, a factor analysis was performed on the 10 cognitive test scores from baseline. To quantify overall cognitive function, a baseline cognitive index was first calculated as the mean of the preoperative domain scores. The cognitive index score has a mean of zero, thus any positive score is above the mean, any negative score is below the mean. A continuous change score was then calculated by subtracting the baseline from the 6-week cognitive index. A negative change score indicating decline and a positive score indicating improvement. The resulting outcome measure is unbounded with a standard deviation of 0.31 in the full surgical cohort.
Time frame: Baseline to 6 weeks
Change in CSF Markers of Alzheimers Disease by Anesthetic Agent Group
CSF Markers of Alzheimer's Disease over time in the subjects treated with propofol versus those treated with isoflurane.
Time frame: Baseline to 6 weeks
Change in Ratio of CSF Markers of Alzheimers Disease by Anesthetic Agent Group
Change in ratio of CSF Markers of Alzheimer's Disease over time in the subjects treated with propofol versus those treated with isoflurane.
Time frame: baseline to 6-weeks
Perioperative CSF Tau/Abeta Ratio Change
The perioperative change in the CSF tau/Abeta ratio from the start of anesthesia/surgery to 24 hours later.
Time frame: Baseline to 24 hours
This platform is for informational purposes only and does not constitute medical advice. Always consult a qualified healthcare professional.