Cardiac surgery with valve replacement temporarily disrupts the hippocampal memory network

Area of Science:

• Neuroscience
• Cardiology
• Immunology

Background:

• Systemic inflammation following heart valve replacement surgery is linked to cognitive impairment.
• Valvular heart disease and post-surgical inflammation may impact cognition and hippocampal functional connectivity (FC).

Purpose of the Study:

• To investigate the effects of valvular heart disease and post-valve replacement surgery inflammation on cognitive function.
• To examine the impact on the functional connectivity (FC) of the hippocampal memory network.

Main Methods:

• Cognitive function tests, inflammatory cytokine measurements, and functional magnetic resonance imaging (fMRI) were used.
• Hippocampal functional connectivity (FC) networks were analyzed before surgery and at 7 and 30 days post-surgery.
• Correlations between FC, memory, and inflammation were assessed using bivariate correlation and structural equation modeling.

Main Results:

• Patients showed impaired memory and decreased hippocampal FC at 7 days post-surgery, associated with increased inflammation.
• Pre-surgery and 7-day post-surgery FC abnormalities normalized by 30 days post-surgery.
• Higher systemic inflammation correlated significantly with poorer memory and reduced hippocampal network FC.

Conclusions:

• Heart valve replacement surgery causes temporary disruption to the hippocampal memory network.
• This disruption leads to transient memory decline.
• The effects are reversible within 30 days post-surgery.