Which risk score best predicts perioperative outcomes in nonvalvular atrial fibrillation patients undergoing noncardiac surgery?

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 (CHADS(2), CHA(2)DS(2)-VASc, and R(2)CHADS(2)) 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 CHADS(2), CHA(2)DS(2)-VASc, and R(2)CHADS(2) 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, CHADS(2) = 1, CHA(2)DS(2)-VASc = 3, and R(2)CHADS(2) = 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 CHADS(2) (NRI 14.3%, P < .001), 0.67 for CHA(2)DS(2)-VASc (NRI 10.7%, P < .001), and 0.68 for R(2)CHADS(2) (NRI 11.4%, P < .001). The CHADS(2), CHA(2)DS(2)-VASc, and R(2)CHADS(2) 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 CHADS(2), CHA(2)DS(2)-VASc, and R(2)CHADS(2) scores all improved the prediction of major perioperative events including mortality compared to the Rd.