title: Dose dependent effect of statins on postoperative atrial fibrillation after cardiac surgery among patients treated with beta blockers.
abstract: BACKGROUND
  Previous studies on the effects of Statins in preventing atrial fibrillation (AF) after cardiac surgery have shown conflicting results. Whether statins prevent AF in patients treated with postoperative beta blockers and whether the statin-effect is dose related are unknown.
  
  
  METHODS
  We retrospectively studied 1936 consecutive patients who underwent coronary artery bypass graft (CABG) (n = 1493) or valve surgery (n = 443) at the Minneapolis Veterans Affairs Medical Center. All patients were in sinus rhythm before the surgery. Postoperative beta blockers were administered routinely (92% within 24 hours postoperatively).
  
  
  RESULTS
  Mean age was 66+10 years and 68% of the patients were taking Statins. Postoperative AF occurred in 588 (30%) patients and led to longer length of stay in the intensive care unit versus those without AF (5.1+7.6 days versus 2.5+2.3 days, p < 0.0001). Patients with a past history of AF had a 5 times higher risk of postoperative AF (odds ratio 5.1; 95% confidence interval 3.4 to 7.7; p < 0.0001). AF occurred in 31% of patients taking statins versus 29% of the others (p = 0.49). In multivariable analysis, statins were not associated with AF (odds ratio (OR) 0.93, 95% confidence interval (CI) 0.7 to 1.2; p = 0.59). However, in a subgroup analysis, the patients treated with Simvastatin >20 mg daily had a 36% reduction in the risk of postoperative AF (OR 0.64, 95% CI 0.43 to 0.6; p = 0.03) in comparison to those taking lower dosages.
  
  
  CONCLUSIONS
  Among cardiac surgery patients treated with postoperative beta blockers Statin treatment reduces the incidence of postoperative AF when used at higher dosages.
authors.affiliation: Department of Internal Medicine, Veterans Affairs Medical Center, Veterans Drive, Minneapolis 55417, USA. salima.mithani@va.gov
authors.forename: Salima
authors.initials: S
authors.lastname: Mithani
authors.forename: Muhammad S
authors.initials: MS
authors.lastname: Akbar
authors.forename: Deborah J
authors.initials: DJ
authors.lastname: Johnson
authors.forename: Michael
authors.initials: M
authors.lastname: Kuskowski
authors.forename: Katherine K
authors.initials: KK
authors.lastname: Apple
authors.forename: Jana
authors.initials: J
authors.lastname: Bonawitz-Conlin
authors.forename: Herbert B
authors.initials: HB
authors.lastname: Ward
authors.forename: Rosemary F
authors.initials: RF
authors.lastname: Kelly
authors.forename: Edward O
authors.initials: EO
authors.lastname: McFalls
authors.forename: Hanna E
authors.initials: HE
authors.lastname: Bloomfield
authors.forename: Jian-Ming
authors.initials: JM
authors.lastname: Li
authors.forename: Selcuk
authors.initials: S
authors.lastname: Adabag
mesh_terms: D000319:Adrenergic beta-Antagonists / Q000627:therapeutic use; D001281:Atrial Fibrillation / Q000209:etiology / Q000517:prevention & control*; D001026:Coronary Artery Bypass / Q000009:adverse effects; D004305:Dose-Response Relationship, Drug; D005260:Female; D006801:Humans; D019161:Hydroxymethylglutaryl-CoA Reductase Inhibitors / Q000008:administration & dosage*; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D011183:Postoperative Complications / Q000517:prevention & control*; D012189:Retrospective Studies; D019821:Simvastatin / Q000008:administration & dosage*; D016896:Treatment Outcome
chemical_list: D000319:Adrenergic beta-Antagonists; D019161:Hydroxymethylglutaryl-CoA Reductase Inhibitors; D019821:Simvastatin