Release of brain-specific creatine kinase and neuron-specific enolase into cerebrospinal fluid after hypothermic and normothermic cardiopulmonary bypass in coronary artery surgery
Coronary artery bypass (CABG) surgery is successfully managed with normothermic cardiopulmonary bypass (CPB) using warm blood cardioplegia. The lack of the protective effect of hypothermia, however, might make the central nervous system vulnerable. Thirty-six patients were randomized into normothermic CPB (36-37 degrees C) (NTCPB group, n=18) and hypothermic CPB (28 degrees C) (HTCPB group, n=18) in order to examine whether normothermic or hypothermic CPB induces the release of the intracellular brain enzymes, creatine kinase (CK), its brain-specific isoenzyme (CK-BB), and neuron-specific enolase (NSE) into cerebrospinal fluid (CSF). In addition, clinical neurologic examination and neuropsychologic assessment were done preoperatively, 5 d and 11-23 mo postoperatively. One patient in each group suffered a stroke after surgery. Two patients in the normothermic group had minor neurologic complications. The cognitive decline after operation was similar in the NTCPB and HTCPB groups. CSF enzymes from normothermic and hypothermic CABG patients without gross neurologic complications were not significantly higher than CSF enzymes from orthopaedic reference patients. CABG patients with neurologic complications had higher enzyme concentrations. Cognitive decline after the operation correlated statistically significantly with CSF enzyme concentrations in the NTCPB group, but not in the HTCPB group. CABG operation without major neurologic complication does not induce the release of CK, CK-BB or NSE enzymes into CSF, irrespective of whether the CPB is normothermic or hypothermic.