S100B as a biomarker of blood-brain barrier disruption after thoracoabdominal aortic aneurysm repair: a secondary analysis from a prospective cohort study.

Purpose: The objective of this study was to determine whether the magnitude of the peripheral inflammatory response to cardiovascular surgery is associated with increases in blood-brain barrier (BBB) permeability as reflected by changes in cerebrospinal fluid (CSF)/plasma S100B concentrations.

Methods: We conducted a secondary analysis from a prospective cohort study of 35 patients undergoing elective thoracoabdominal aortic aneurysm repair with (n = 17) or without (n = 18) cardiopulmonary bypass (CPB). Plasma and CSF S100B, interleukin-6 (IL-6), and albumin concentrations were measured at baseline (C) and serially for up to five days.

Results: Following CPB, the median [interquartile range] plasma S100B concentration increased from 58 [32-88] pg·mL at C to a maximum concentration (C) of 1,131 [655-1,875] pg·mL over a median time (t) of 6.3 [5.9-7.0] hr. In the non-CPB group, the median plasma S100B increased to a lesser extent. There was a delayed increase in CSF S100B to a median C of 436 [406-922] pg·mL in the CPB group at a t of 23.7 [18.5-40.2] hr. In the non-CPB group, the CSF concentrations were similar at all time points. In the CPB group, we did not detect significant correlations between plasma and CSF S100B with plasma IL-6 [r = 0.52 (95% confidence interval [CI], -0.061 to 0.84)] and CSF IL-6 [r = 0.53 (95% CI, -0.073 to 0.85)] concentrations, respectively. Correlations of plasma or CSF S100B levels with BBB permeability were not significant.

Conclusion: The lack of parallel increases in plasma and CSF S100B following CPB indicates that S100B may not be a reliable biomarker for BBB disruption after thoracoabdominal aortic aneurysm repair employing CPB.

Trial Registration: www.clinicaltrials.gov (NCT00878371); registered 7 April 2009.