title: Perioperative atrial fibrillation and the long-term risk of ischemic stroke.
abstract: OBJECTIVE
  Clinically apparent atrial fibrillation increases the risk of ischemic stroke. In contrast, perioperative atrial fibrillation may be viewed as a transient response to physiological stress, and the long-term risk of stroke after perioperative atrial fibrillation is unclear.
  
  
  OBJECTIVE
  To examine the association between perioperative atrial fibrillation and the long-term risk of stroke.
  
  
  METHODS
  Retrospective cohort study using administrative claims data on patients hospitalized for surgery (as defined by surgical diagnosis related group codes), and discharged alive and free of documented cerebrovascular disease or preexisting atrial fibrillation from nonfederal California acute care hospitals between 2007 and 2011. Patients undergoing cardiac vs other types of surgery were analyzed separately.
  
  
  METHODS
  Previously validated diagnosis codes were used to identify ischemic strokes after discharge from the index hospitalization for surgery. The primary predictor variable was atrial fibrillation newly diagnosed during the index hospitalization, as defined by previously validated present-on-admission codes. Patients were censored at postdischarge emergency department encounters or hospitalizations with a recorded diagnosis of atrial fibrillation.
  
  
  RESULTS
  Of 1,729,360 eligible patients, 24,711 (1.43%; 95% CI, 1.41%-1.45%) had new-onset perioperative atrial fibrillation during the index hospitalization and 13,952 (0.81%; 95% CI, 0.79%-0.82%) experienced a stroke after discharge. At 1 year after hospitalization for cardiac surgery, cumulative rates of stroke were 0.99% (95% CI, 0.81%-1.20%) in those with perioperative atrial fibrillation and 0.83% (95% CI, 0.76%-0.91%) in those without atrial fibrillation. At 1 year after noncardiac surgery, cumulative rates of stroke were 1.47% (95% CI, 1.24%-1.75%) in those with perioperative atrial fibrillation and 0.36% (95% CI, 0.35%-0.37%) in those without atrial fibrillation. In a Cox proportional hazards analysis accounting for potential confounders, perioperative atrial fibrillation was associated with subsequent stroke both after cardiac surgery (hazard ratio, 1.3; 95% CI, 1.1-1.6) and noncardiac surgery (hazard ratio, 2.0; 95% CI, 1.7-2.3). The association was significantly stronger for perioperative atrial fibrillation after noncardiac vs cardiac surgery (P < .001 for interaction).
  
  
  CONCLUSIONS
  Among patients hospitalized for surgery, perioperative atrial fibrillation was associated with an increased long-term risk of ischemic stroke, especially following noncardiac surgery.
authors.affiliation: Feil Family Brain and Mind Research Institute, Weill Cornell Medical College, New York, New York.
authors.forename: Gino
authors.initials: G
authors.lastname: Gialdini
authors.affiliation: Department of Neurology, Weill Cornell Medical College, New York, New York.
authors.forename: Katherine
authors.initials: K
authors.lastname: Nearing
authors.affiliation: Division of Cardiology, University of Iowa Carver College of Medicine, Iowa City.
authors.forename: Prashant D
authors.initials: PD
authors.lastname: Bhave
authors.affiliation: Section of Neurology, Department of Clinical and Experimental Medicine, University of Pisa, Pisa, Italy.
authors.forename: Ubaldo
authors.initials: U
authors.lastname: Bonuccelli
authors.affiliation: Feil Family Brain and Mind Research Institute, Weill Cornell Medical College, New York, New York2Department of Neurology, Weill Cornell Medical College, New York, New York.
authors.forename: Costantino
authors.initials: C
authors.lastname: Iadecola
authors.affiliation: Population Health Research Institute, McMaster University, Hamilton, Ontario, Canada.
authors.forename: Jeff S
authors.initials: JS
authors.lastname: Healey
authors.affiliation: Feil Family Brain and Mind Research Institute, Weill Cornell Medical College, New York, New York2Department of Neurology, Weill Cornell Medical College, New York, New York.
authors.forename: Hooman
authors.initials: H
authors.lastname: Kamel
mesh_terms: D000328:Adult; D000368:Aged; D001281:Atrial Fibrillation / Q000150:complications*; D005260:Female; D006760:Hospitalization; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D059035:Perioperative Period; D016016:Proportional Hazards Models; D012189:Retrospective Studies; D012307:Risk Factors; D020521:Stroke / Q000209:etiology*; D013514:Surgical Procedures, Operative