Associations Between Mean Arterial Pressure During Cardiopulmonary Bypass And Biomarkers Of Cerebral Injury In Patients Undergoing Cardiac Surgery: Secondary Results From A Randomized Controlled Trial

OBJECTIVES: Cardiac surgery is associated with risk of cerebral injury and mean arterial pressure (MAP) during cardiopulmonary bypass (CPB) is suggested to be associated with cerebral injury. The `Perfusion Pressure Cerebral Infarcts' (PPCI) trial randomized patients undergoing coronary artery bypass grafting (CABG) and/or aortic valve replacement to a MAP of 40-50 or 70-80 mmHg during CPB and found no difference in clinical or imaging outcomes between the groups. We here present PPCI trial predefined secondary end points, consisting of biomarkers of brain injury.METHODS: Blood was collected from PPCI trial patients at baseline, 24 and 48 h after induction of anaesthesia and at discharge from the surgical ward. Blood was analysed for neuron-specific enolase, tau, neurofilament light and the glial marker glial fibrillary acidic protein. Linear mixed models were used to analyse differences in biomarker value changes from baseline between the 2 MAP allocation groups.RESULTS: A total of 193 (98%) patients were included. We found no differences in biomarker levels over time from baseline to discharge between the 2 MAP allocation groups (P-NSE = 0.14, P-Tau = 0.46, P-NFL = 0.21, P-GFAP = 0.13) and the result did not change after adjustment for age, sex and type of surgery.CONCLUSIONS: We found no significant differences in levels of biomarkers of neurological injury in patients undergoing elective or subacute CABG and/or aortic valve replacement randomized to either a target MAP of 40-50 mmHg or a target MAP of 70-80 mmHg during CBP.