Inflammation Disrupts the Brain Network of Executive Function After Cardiac Surgery

Objective To investigate postoperative functional connectivity alterations across impaired cognitive domains and their causal relationships with systemic inflammation. Background Postoperative cognitive dysfunction commonly occurs after cardiac surgery, and both systemic and neuroinflammation may trigger its development. Whether functional connectivity alterations underlying deficits in specific cognitive domains after cardiac surgery are affected by inflammation remain unclear. Methods Seventeen patients, who underwent cardiac valve replacement, completed a neuropsychological test battery and brain MRI scan before surgery and on days 7 and 30 after surgery compared to age-matched healthy controls. Blood samples were taken for TNF-α and IL-6 measurements. Seed-to-voxel FC of the left dorsolateral prefrontal cortex (DLPFC) was examined. Bivariate correlation and linear regression models were used to determine the relationships among cognitive function, FC alterations and cytokines. Results Executive function was significantly impaired after cardiac surgery. At day 7 follow-up, the surgical patients, compared to the controls, demonstrated significantly decreased DLPFC functional connectivity with the superior parietal lobe and attenuated negative connectivity in the default mode network, including the angular gyrus and posterior cingulate cortex. The left DLPFC enhanced the connectivity in the right DLPFC and posterior cingulate cortex, all of which were related to the increased TNF-α and decreased executive function up to day 7 after cardiac surgery. Conclusions The decreased functional connectivity of executive control network and its anticorrelation with the default mode network may contribute to executive function deficits following cardiac surgery. Systemic inflammation may trigger these transient FC changes and executive function impairments.