A comparison of four risk models for the prediction of cardiovascular complications in patients with a history of atrial fibrillation undergoing non-cardiac surgery

It is unclear how best to predict peri-operative cardiovascular risk in patients with atrial fibrillation undergoing non-cardiac surgery. This study examined the accuracy of the revised cardiac risk index and three atrial fibrillation thrombo-embolic risk models for predicting 30-day cardiovascular events after non-cardiac surgery in patients with a pre-operative history of atrial fibrillation. We conducted a prospective cohort study in 28 centres from 2007 to 2013 of 40,004 patients ≥ 45 years of age undergoing inpatient non-cardiac surgery who were followed until 30 days after surgery for cardiovascular events (defined as myocardial injury, heart failure, stroke, resuscitated cardiac arrest or cardiovascular death). The 2088 patients with a pre-operative history of atrial fibrillation were at higher risk of peri-operative cardiovascular events compared with the 34,830 patients without a history of atrial fibrillation (29% vs. 13%, respectively, adjusted odds ratio 1.30 (95%CI 1.17-1.45). Compared with the revised cardiac risk index (c-index 0.60), all atrial fibrillation thrombo-embolic risk scores were significantly better at predicting peri-operative cardiovascular events: CHADS₂ (c-index 0.62); CHA₂ DS₂ -VASc (c-index 0.63); and R₂ CHADS₂ (c-index 0.65), respectively. Although the three thrombo-embolic risk prediction models were significantly better than the revised cardiac risk index for prediction of peri-operative cardiovascular events, none of the four models exhibited strong discrimination metrics. There remains a need to develop a better peri-operative risk prediction model.