Early Detection of Brain Damage in Children With Congenital Heart Disease After Cardiovascular Surgery

This prospective observational study will enrol 30 children up to 1 year of age with congenital heart disease requiring surgery with extracorporeal circulation at a single paediatric intensive care centre. After parental/guardian consent, peripheral blood will be collected for ELISA measurement of secretoneurin, GFAP, neuron-specific enolase, S100B, UCHL-1, neurofilament light chain, and total tau at the following time points: within 24 hours preoperatively; 1 hour after arrival from the operating theatre; and 24, 48, 72, 96 hours and 7 days postoperatively. All participants will undergo EEG within the first 24 hours and on postoperative day 7. Between postoperative week 1 and week 2, 15 participants will undergo brain MRI under sedation or general anaesthesia. Perioperative and postoperative clinical variables will be abstracted (e.g., cardiopulmonary bypass duration, major artery clamp duration, inotrope/vasoactive support, arrhythmias, and markers of organ hypoperfusion including lactate and regional oxygen saturation). Associations between biomarker trajectories and EEG/MRI evidence of brain injury will be assessed using repeated-measures modelling; ROC analyses will explore biomarker thresholds where applicable.