The impact of S100b and persistent high levels of neuron-specific enolase on cognitive performance in elderly patients after cardio-pulmonary bypass

Primary objectives: The primary aim was to investigate the impact of neuron-specific enolase (NSE) and S100 calcium-binding protein B (S100b) on cognitive functioning after cardiopulmonary bypass (CPB). Research design: Prospective exploratory study. Setting: Psychiatric Consultation-Liaison Service, Ludwig-Maximilians-University Medical School, Munich, Germany. Participants: Thirty-four patients who underwent elective CPB. Measurements: Before the CPB and on the day before discharge neurocognitive tests based on the Syndrom Kurztest (SKT) were carried out. During the ICU stay and shortly after discharge from the ICU, the delirious state was evaluated daily using the Delirium-Rating-Scale. NSE and S100b levels were assayed before CPB, 24 hours and 48 hours post-operatively and on the day before discharge. Results: After the CPB, 1 day before discharge, six (17.6%) participants had sub-threshold cognitive deficits and seven (20.6%) had clinically significant cognitive deficits. A trend toward persistently high NSE levels at discharge indicates greater cognitive impairment at the time of discharge. After surgical intervention S100b is elevated in all patients, independent of cognitive status. Conclusions: Persistently high levels of NSE might be a useful biomarker to identify patients with cognitive performance impairments, while no significant correlation between levels of S100b and impaired cognitive function were found.