Glial fibrillary acidic protein plasma levels are correlated with degree of hypothermia during cardiopulmonary bypass in congenital heart disease surgery.
Objectives
Improved congenital heart defect (CHD) operations have reduced operative mortality to 3%. The major concern is now long-term neurological outcomes. We measured plasma glial fibrillary acidic protein (GFAP), an early marker of brain injury, during different phases of cardiopulmonary bypass (CPB), to correlate the increase of GFAP to clinical parameters or specific operative phases.


Methods
We performed a prospective, single-centre, observational study in children undergoing cardiac operations. We studied 69 children with CHD and biventricular heart physiology: 26 had tetralogy of Fallot; 17 transposition of the great arteries; and 26 ventricular/atrial septal defects with or without associated arch defects. GFAP levels were measured by ELISA at different stages of CPB. We recorded clinical and surgical parameters and applied multivariable and logistic regressions to assess which parameters were independent predictors of variations in plasma GFAP.


Results
GFAP increased during CPB and peaked at the end of rewarming. Multivariable regression showed degree of hypothermia as the only significant independent predictor of GFAP increase, adjusted for age, prematurity, type of CHD, cyanosis, aortic cross-clamp time, haemodilution, neurological risk time interval and rewarming rate. Temperature nadir and neurological risk time interval were significant independent predictors of a GFAP value  > 0.46 ng/ml.


Conclusions
Hypothermia degree during CPB is correlated with GFAP plasma increase in children with biventricular heart defects undergoing surgical repair. Rewarming is the most critical CPB phase for GFAP increase. The implication of high plasma GFAP is still under evaluation. Follow-up studies are ongoing to assess the reliability of GFAP as a marker of brain injury and/or as a predictor of neurodevelopmental abnormalities.
['Vedovelli|Luca|L|', 'Padalino|Massimo|M|', "D'Aronco|Sara|S|", 'Stellin|Giovanni|G|', 'Ori|Carlo|C|', 'Carnielli|Virgilio P|VP|', 'Simonato|Manuela|M|', 'Cogo|Paola|P|']
D015415:Biomarkers D001831:Body Temperature D001930:Brain Injuries D002315:Cardiopulmonary Bypass D005260:Female D005500:Follow-Up Studies D005904:Glial Fibrillary Acidic Protein D006330:Heart Defects, Congenital D006801:Humans D007035:Hypothermia D007036:Hypothermia, Induced D007223:Infant D008297:Male D011446:Prospective Studies D015203:Reproducibility of Results D012720:Severity of Illness Index
Congenital heart disease GFAP Brain injury Biomarkers Paediatrics White matter