Cerebrospinal fluid creatine kinase-BB isoenzyme activity and outcome after subarachnoid hemorrhage

Background: The brain is rich in creatine kinase-BB isoenzyme activity (CK- BB), which is not normally present in cerebrospinal fluid (CSF). Results of previous studies have shown that CK-BB can be detected in the CSF of patie nts with aneurysmal subarachnoid hemorrhage (SAH), but whether CK-BB levels correlate with patients; neurologic outcomes is unknown. Objective: To evaluate the relationship between CSF CK-BB level and outcome after SAH. Design: Prospective observational cohort. Setting: University-affiliated tertiary care center. Patients: Convenience sample of 30 patients seen for cerebral aneurysm flip ping. Interventions: We sampled and assayed CSF for CK isoenzymes a median of 3 d ays after SAH in 27 patients, and at;he time of unruptured aneurysm clippin g in 3 patients. Main Outcome Measures: Without knowledge of CK results, we assigned the Gla sgow Outcome Scale score early (approximate to 1 week) and late (approximat e to 2 months) after surgery. Results: Higher CSF CK-BB levels were associated with higher Hunt and Hess grades at hospital admission (Spearman rank correlation, rho = 0.69; P < .0 01), lower Glasgow Coma Scale scores at hospital admission (rho = -0.72; P < .001), and worse early outcomes on the Glasgow Outcome Scale (rho = -0.64 , P < .001). For patients with a favorable early outcome (Glasgow Outcome S cale score, 3-5), all CK-BB levels were less than 40 U/L. With a cutoff val ue of 40 U/L, CK-BB had a sensitivity of 70% and a specificity of 100% for predicting unfavorable early outcome (Glasgow Outcome Scale score, 1-2). Ha ving a CK-BB level greater than 40 U/L increased the chance of an unfavorab le early outcome, from 33% (previous probability) to 100%, whereas a CK-BB level of 40 U/L or less decreased it to 13%. Similar findings were obtained when considering late outcomes. Conclusion: The level of CSF CK-BB may help predict neurologic outcome afte r SAH.