title: Which risk score best predicts perioperative outcomes in nonvalvular atrial fibrillation patients undergoing noncardiac surgery?
abstract: BACKGROUND
  Patients with nonvalvular atrial fibrillation (NVAF) are at increased risk for adverse events after noncardiac surgery. The Revised Cardiac Index (RCI) is commonly used to predict perioperative events; however, the prognostic utility of NVAF risk scores (CHADS2, CHA2DS2-VASc, and R2CHADS2) has not been evaluated in patients undergoing noncardiac surgery.
  
  
  METHODS
  Using a population-based data set of NVAF patients (n = 32,160) who underwent major or minor noncardiac surgery between April 1, 1999, and November 30, 2009, in Alberta, Canada, we examined the incremental prognostic value of the CHADS2, CHA2DS2-VASc, and R2CHADS2 scores over the RCI using continuous net reclassification improvement (NRI). The primary composite outcome was 30-day mortality, stroke, transient ischemic attack, or systemic embolism.
  
  
  RESULTS
  The median age was 73 years, 55.1% were male, 6.6% had a previous thromboembolism, 17% of patients underwent major surgery, and the median risk scores were as follows: RCI = 1, CHADS2 = 1, CHA2DS2-VASc = 3, and R2CHADS2 = 2. The incidence of our 30-day composite was 4.2% (mortality 3.3%; stroke, transient ischemic attack, or systemic embolism 1.2%); and c indices were 0.65 for the RCI, 0.67 for the CHADS2 (NRI 14.3%, P < .001), 0.67 for CHA2DS2-VASc (NRI 10.7%, P < .001), and 0.68 for R2CHADS2 (NRI 11.4%, P < .001). The CHADS2, CHA2DS2-VASc, and R2CHADS2 scores were also all significantly better than the RCI for mortality risk prediction (NRI 12.3%, 8.4%, and 13.3%, respectively; all Ps < .01).
  
  
  CONCLUSIONS
  In NVAF patients undergoing noncardiac surgery, the CHADS2, CHA2DS2-VASc, and R2CHADS2 scores all improved the prediction of major perioperative events including mortality compared to the RCI.
authors: Divisions of Critical Care and Cardiology, University of Alberta, Edmonton, Alberta, Canada. Electronic address: sv9@ualberta.ca.
authors: Sean
authors: S
authors: van Diepen
authors: Patient Health Outcomes Research and Clinical Effectiveness Unit, University of Alberta, Edmonton, Alberta, Canada.
authors: Erik
authors: E
authors: Youngson
authors: Division of Cardiology, Department of Medicine, University of Alberta, Edmonton, Alberta, Canada.
authors: Justin A
authors: JA
authors: Ezekowitz
authors: Patient Health Outcomes Research and Clinical Effectiveness Unit, University of Alberta, Edmonton, Alberta, Canada; Division of General Internal Medicine, Department of Medicine, University of Alberta, Edmonton, Alberta, Canada.
authors: Finlay A
authors: FA
authors: McAlister
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000416:Alberta / Q000453:epidemiology; D001281:Atrial Fibrillation / Q000150:complications / Q000453:epidemiology*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D059035:Perioperative Period; D011159:Population Surveillance; D011183:Postoperative Complications / Q000453:epidemiology* / Q000209:etiology; D015995:Prevalence; D011379:Prognosis; D012189:Retrospective Studies; D018570:Risk Assessment / Q000379:methods*; D012307:Risk Factors; D013514:Surgical Procedures, Operative; D015996:Survival Rate / Q000639:trends