Preoperative blood-brain barrier disruption increased risk of postoperative cognitive decline after coronary artery bypass grafting: a prospective cohort study

Background: Cognitive decline after coronary artery bypass grafting (CABG) surgery is common and significantly impacts the long-term prognosis of coronary artery disease (CAD) patients. Nevertheless, the mechanisms of postoperative cognitive decline (POCD) and its early neuroimaging indicators remain unclear. Objectives: To explore whether blood-brain barrier disruption of computed tomography perfusion (CTP) is associated with POCD in patients with CABG. Methods: The study involved 116 participants (mean age 63.85 ± 8.10 years) with CAD who underwent CABG surgery as part of the IACV Study. A CTP scan was performed before the surgery to assess the permeable surface (PS) values of the frontal and temporal lobes. The Montreal Cognitive Assessment (MoCA) neurological scale was used to measure cognitive function before the surgery and again before discharge. Results: Overall, 24 (20.69%) developed POCD. All patients underwent the same anesthesia and postoperative analgesia, with no difference in postoperative blood loss and days of hospital discharge between the two groups. Patients with POCD exhibited higher PS in the right frontal lobe (0.20 [0.10, 0.30] vs 0.13 [0.07, 0.18], P = 0.009) and left frontal lobe (0.23 [0.11, 0.28] vs 0.14 [0.08, 0.22], P = 0.030). A notable decrease in total MoCA scores from 20.7 to 14.0 was seen in patients with POCD. Each 0.05 ml/100 g/min increase in PS of the right frontal lobe was associated with 1.32 times increase in the risk of developing POCD. Higher baseline PS values correlated with a greater decline in MoCA scores post-surgery ( ρ = −0.231, P = 0.0214). Conclusions: Almost one-fifth of patients develop POCD following CABG surgery, and preoperative elevation of frontal lobe PS is associated with POCD. These findings suggest that CTP-PS may serve as an imaging biomarker to identify patients at high risk for POCD.