Association between preoperative blood-brain barrier permeability and postoperative delirium in older patients undergoing cardiac surgery: a pilot study.

Background: Postoperative delirium (POD) is a frequent and serious complication in older adults after cardiac surgery. Blood-brain barrier (BBB) dysfunction is implicated in cognitive decline, but its preoperative role in POD remains underexplored. This pilot study aimed to investigate the association between preoperative regional BBB permeability, assessed by dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI), and POD in older patients undergoing off-pump coronary artery bypass grafting (OPCABG).

Gut dysbiosis is associated with increased blood-brain barrier permeability and cognitive impairment in elderlies with coronary heart disease.

Objective: The gut-brain axis is recognized as a critical pathway through which gut microbiota influences neurological health. However, the complex interplay between gut microbiota composition, blood-brain barrier (BBB) integrity, and cognitive function in elderly individuals with coronary heart disease (CHD) experiencing mild cognitive impairment (MCI) remains insufficiently elucidated. This study aimed to investigate these relationships in a cohort of 40 elderlies with CHD, comparing those with MCI to those with normal cognition (NC), focusing on microbial diversity, specific taxa alterations, BBB permeability, and their correlations with cognitive performance.