title: Serum protein S100 as marker of postoperative delirium after off-pump coronary artery bypass surgery: secondary analysis of two prospective randomized controlled trials.
abstract: BACKGROUND
  To investigate the predictive value of S100 (biochemical marker of neuroglial injury) for the occurrence of postoperative delirium (POD) in patients undergoing off-pump coronary artery bypass (OPCAB)-surgery.
  
  
  METHODS
  We enrolled 92 patients older than 18 years undergoing elective OPCAB-surgery. Serum-levels of S100 were determined at baseline (BL), end of surgery (EOS) and on the first postoperative day (PD1). Postoperatively, all-patients were evaluated daily until PD5 for the presence of POD using the confusion assessment method (CAM) or the confusion assessment method for the intensive care unit (CAM-ICU) for patients in the intensive care unit (ICU).
  
  
  RESULTS
  The overall incidence of POD was 21%. S100-values on PD1 significantly predicted the occurrence of POD during the later hospital stay [area under the curve (AUC)=0.724 (95% confidence interval (CI): 0.619-0.814); p=0.0001] with an optimal cut-off level of 123 pg mL-1 (sensitivity 100%, specificity 44%). Below this value, the absence of POD was predicted correctly in 43.66% of patients without POD [negative predictive value (NPV) of 100% (95%CI: 88.8%-100.0%) - positive predictive value of 29.8% (95%CI: 18.4%-43.4%) and likelihood ratio (LR) of the negative result of 0.0].
  
  
  CONCLUSIONS
  S100-levels <123 pg mL-1 measured on PD1 reliably rule out the development of POD after elective OPCAB-surgery. This finding warrants testing whether S100-levels could be used for a risk stratification of cardiac surgical patients and for the initiation of preventive measures against POD in patients with high postoperative S100-levels.
authors.forename: Layth
authors.initials: L
authors.lastname: Al Tmimi
authors.forename: Marc
authors.initials: M
authors.lastname: Van de Velde
authors.forename: Bart
authors.initials: B
authors.lastname: Meyns
authors.forename: Bart
authors.initials: B
authors.lastname: Meuris
authors.forename: Paul
authors.initials: P
authors.lastname: Sergeant
authors.forename: Koen
authors.initials: K
authors.lastname: Milisen
authors.forename: Hans
authors.initials: H
authors.lastname: Pottel
authors.forename: Koen
authors.initials: K
authors.lastname: Poesen
authors.forename: Steffen
authors.initials: S
authors.lastname: Rex
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015415:Biomarkers / Q000097:blood*; D002318:Cardiovascular Diseases / Q000601:surgery*; D047549:Coronary Artery Bypass, Off-Pump / Q000009:adverse effects*; D003693:Delirium / Q000097:blood / Q000175:diagnosis* / Q000209:etiology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011183:Postoperative Complications; D011379:Prognosis; D011446:Prospective Studies; D009418:S100 Proteins / Q000097:blood*
chemical_list: D015415:Biomarkers; D009418:S100 Proteins