Is there a relationship between serum S-100 beta protein and neuropsychologic dysfunction after cardiopulmonary bypass?

Objectives: Over the past decade, the glial protein S-100 beta has been used to detect cerebral injury in a number of clinical settings including cardiac surgery. Previous investigations suggest that S-100 beta is capable of identifying patients with cerebral dysfunction after cardiopulmonary bypass. Whether detection of elevated levels S-100 beta reflects long-term cognitive impairment remains to be shown. The present study evaluated whether perioperative release of S-100 beta after coronary artery operations with cardiopulmonary bypass could predict early or late neuropsychologic impairment. Methods: A total of 100 patients undergoing elective coronary bypass without a previous history of neurologic events were prospectively studied. To exclude noncerebral sources of S-100 beta, we did not use cardiotomy suction or retransfusion of shed mediastinal blood. Serial perioperative measurements of S-100 beta were performed with the use of a new sensitive immunoluminometric assay up to 8 hours after the operation. Patients underwent cognitive testing on a battery of 11 tests before the operation, before discharge from the hospital, and 3 months later. Results: No significant correlation was found between S-100 beta release and neuropsychologic measures either 5 days or 3 months after the operation, Conclusion: Despite using a sensitive immunoluminometric assay of S-100 beta, we found no evidence to support the suggestion that early release of S-100 beta may reflect long-term neurologic injury capable of producing cognitive impairment.