title: Preoperative neutrophil-lymphocyte ratio and outcome from coronary artery bypass grafting.
abstract: BACKGROUND
  An elevated preoperative white blood cell count has been associated with a worse outcome after coronary artery bypass grafting (CABG). Leukocyte subtypes, and particularly the neutrophil-lymphocyte (N/L) ratio, may however, convey superior prognostic information. We hypothesized that the N/L ratio would predict the outcome of patients undergoing surgical revascularization.
  
  
  METHODS
  Baseline clinical details were obtained prospectively in 1938 patients undergoing CABG. The differential leukocyte was measured before surgery, and patients were followed-up 3.6 years later. The primary end point was all-cause mortality.
  
  
  RESULTS
  The preoperative N/L ratio was a powerful univariable predictor of mortality (hazard ratio [HR] 1.13 per unit, P < .001). In a backward conditional model, including all study variables, it remained a strong predictor (HR 1.09 per unit, P = .004). In a further model, including the European system for cardiac operative risk evaluation, the N/L ratio remained an independent predictor (HR 1.08 per unit, P = .008). Likewise, it was an independent predictor of cardiovascular mortality and predicted death in the subgroup of patients with a normal white blood cell count. This excess hazard was concentrated in patients with an N/L ratio in the upper quartile (>3.36).
  
  
  CONCLUSIONS
  An elevated N/L ratio is associated with a poorer survival after CABG. This prognostic utility is independent of other recognized risk factors.
authors.affiliation: Department of Cardiology, University of Aberdeen and Aberdeen Royal Infirmary, Aberdeen, United Kingdom.
authors.forename: Patrick H
authors.initials: PH
authors.lastname: Gibson
authors.forename: Bernard L
authors.initials: BL
authors.lastname: Croal
authors.forename: Brian H
authors.initials: BH
authors.lastname: Cuthbertson
authors.forename: Gary R
authors.initials: GR
authors.lastname: Small
authors.forename: Adaeze I
authors.initials: AI
authors.lastname: Ifezulike
authors.forename: George
authors.initials: G
authors.lastname: Gibson
authors.forename: Robert R
authors.initials: RR
authors.lastname: Jeffrey
authors.forename: Keith G
authors.initials: KG
authors.lastname: Buchan
authors.forename: Hussein
authors.initials: H
authors.lastname: El-Shafei
authors.forename: Graham S
authors.initials: GS
authors.lastname: Hillis
mesh_terms: D000368:Aged; D001026:Coronary Artery Bypass / Q000379:methods*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007958:Leukocyte Count; D008214:Lymphocytes / Q000473:pathology*; D008297:Male; D017202:Myocardial Ischemia / Q000097:blood* / Q000401:mortality / Q000601:surgery; D009504:Neutrophils / Q000473:pathology*; D011379:Prognosis; D012189:Retrospective Studies; D015996:Survival Rate