Total Tau protein as a novel biomarker for detection of neural injury following cardiopulmonary bypass in pediatric congenital heart surgery patients.

Objective: To investigate the association of Tau protein levels with postoperative evidence of neural injury following cardiopulmonary bypass (CPB) in pediatric cardiac surgery patients. Methods: One hundred forty-four consecutive pediatric cardiac surgery patients were recruited. Whole blood (3 mL) was collected in EDTA tubes from an arterial line at 5 time points: pre-midline incision, at 3 to 5 minutes on CPB, just prior to weaning from CPB, at 1 hour post-CPB, and at 24 hours post-CPB. Plasma was analyzed via an automated immunoassay for total Tau, a protein linked to brain injury. Tau levels over time were compared between 2 patient groups: age (neonates/infants age <365 days vs children age ≥365 days) and type of heart disease (cyanotic vs acyanotic). Results: Thirty-six patients had postoperative evidence of neural injury. Tau levels over time differed between the 2 groups. At the end of CPB and at 1 hour post-CPB, there were significant differences between patients stratified by age (neonates and infants vs older children; P < .001) and by type of congenital heart disease (cyanotic vs acyanotic; P < .05). At 24 hours post-CPB, each 10-pg/mL increase in total Tau corresponded to a 12% increased risk of neural injury (odds ratio, 1.122; 95% confidence interval, 1.043-1.206; P = .002). When stratified by neural injury, age, and type of congenital heart disease, Tau remained persistently elevated in all patients post-CPB compared to respective baseline levels (P < .001). Conclusions: 24-hour post-CPB plasma Tau may be a reliable marker of neural injury in the pediatric congenital heart surgery population.