title: Middle-aged men with increased waist circumference and elevated C-reactive protein level are at higher risk for postoperative atrial fibrillation following coronary artery bypass grafting surgery.
abstract: BACKGROUND
  We recently demonstrated that metabolic syndrome (MetS) is an independent risk factor for postoperative atrial fibrillation (POAF) following coronary artery bypass grafting (CABG). In the present work, we sought to determine which feature of the MetS is associated with POAF.
  
  
  RESULTS
  We retrospectively analysed the association between metabolic features and the incidence of new-onset POAF in a total of 2214 male patients <65 years who underwent first isolated CABG. Anthropometric data including waist circumference (WC) and complete preoperative lipid profile were available. We also conducted a nested case-control substudy including 147 patients who developed POAF, and were matched for age with a control population. In these patients, C-reactive protein, interleukin-6 (IL-6), and thiobarbituric acid-reactive substances (TBARS; evaluating the oxidative stress) blood levels were determined. In the whole cohort, 19.6% of patients developed POAF. On univariate analysis, body mass index (BMI; P = 0.002) and WC (P = 0.001) were the only anthropometric variables significantly associated with increased incidence of POAF. In the multivariable logistic model, the only independent predictors of POAF were a WC > 102 cm [odds ratio (OR) = 1.40, P = 0.04)] and older age (OR = 1.08, P < 0.001). In the nested case-control substudy C-reactive protein, IL-6, and TBARS levels were not significantly different in patients with or without POAF. Of particular significance, patients with elevated WC > 102 cm and C-reactive protein > 1.5 mg/L or IL-6 >2.2 pg/mL were at a high risk of developing POAF (respectively, OR = 2.32, P = 0.02 and OR = 2.27, P = 0.03).
  
  
  CONCLUSIONS
  Patients with increased WC combined with elevated C-reactive protein levels are at higher risk for POAF. Thus, interventions targeting inflammation related to visceral obesity might help reducing the incidence of POAF.
authors.affiliation: Department of Surgery, Laval University, 2725 Chemin Ste-Foy, Quebec, Canada G1V-4G5.
authors.forename: Nicolas
authors.initials: N
authors.lastname: Girerd
authors.forename: Philippe
authors.initials: P
authors.lastname: Pibarot
authors.forename: Dominique
authors.initials: D
authors.lastname: Fournier
authors.forename: Pascal
authors.initials: P
authors.lastname: Daleau
authors.forename: Pierre
authors.initials: P
authors.lastname: Voisine
authors.forename: Gilles
authors.initials: G
authors.lastname: O'Hara
authors.forename: Jean-Pierre
authors.initials: JP
authors.lastname: Després
authors.forename: Patrick
authors.initials: P
authors.lastname: Mathieu