American Surgical Association
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Serologic Markers of Brain Injury Associated to Cognitive Function After Cardiopulmonary Bypass
Basel Ramlawi, M.D.*, James L. Rudolph, MD*, Shigetoshi Mieno, MD*, Jun Feng, MD, PhD*, Cesario Bianchi, MD, PhD*, Kamal Khabbaz, M.D.*, Munir Boodhwani, M.D.*, Sue E. Kevkoff, ScD*, Edward R. Marcantonio, MD*, Frank W. Sellke, MD
BIDMC - Harvard Medical School, Boston, MA, BIDMC - Harvard Medical School, Brookline, MA, BIDMC - Harvard Medical School, Brookline, MA, BIDMC - Harvard Medical School, Brookline, MA

Objective: Neurologic injury following cardiac surgery ranges from debilitating stroke to subtle neurocognitive deficits(NCD). The clinical role of serologic markers of brain injury has been limited due to lack of reliability. We studied markers of central nervous system(CNS) injury in relation to clinical neurologic outcome (NCD) following cardiopulmonary bypass(CPB).
Methods: Forty patients, enrolled prospectively, undergoing CABG and/or valve surgery with CPB were administered a neurocognitive battery preoperatively and postoperatively(POD4). Battery consisted of validated assessments covering memory, executive function, naming, attention, fluency and premorbid intelligence. NCD was defined as one standard deviation from baseline on ≥25% of tasks. CNS injury was assessed through increase in levels of serum axonal Tau protein (dichotomous variable) and s100ß protein. Analysis of Variance(ANOVA), Mann-Whitney and Spearman Correlation were used for statistical analysis.
Results: Patients studied had an NCD rate of 40% (16 of 40) with a mean age 73±3.9 years. Characteristics at baseline and known predictors of NCD such as age, education level and perioperative temperature were not significantly different between patients with/without NCD. Both s100ß and Tau protein were significantly more elevated following CPB in patients with NCD compared to patients without NCD as described in table below. Moreover, NCD patients had a prolonged elevation in s100ß that persisted until the POD4 measurement.
Conclusions: Subtle CNS injury following CPB, such as NCD, is associated with elevations in markers of axonal CNS injury after surgery. Combining these serologic tests would potentially enhance diagnostic accuracy of these complications.
S100ß and Tau Protein Associated to NCD in Cardiac Surgical Patients
MarkerNCD Group
No NCD Group
p-ValueStatistical Test
S100ß - µg/L (Pre/6hrs/POD4)Inter-group effect0.031Rep. Meas. ANOVA
S100ß - Pre Surgery13.8±9.820.1±6.3NS(0.38)Mann-Whitney
S100ß - 6 Hrs post CPB59.6±36.929.3±14.30.028Mann-Whitney
S100ß - POD 416.0±4.93.6±1.70.011Mann-Whitney
Tau Protein(%Increase pre vs 6hrs)81%21%0.019Spearman Correlation

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