Derivation and Validation of a Clinical Score for Predicting Postoperative Atrial Fibrillation in Noncardiac Elective Surgery (the HART Score)

Postoperative atrial fibrillation (POAF) represents the most frequent cardiac arrhythmia in the surgical setting. It affects almost 3% of all patients over 45 years old who underwent noncardiovascular surgery and is associated with a higher risk of stroke, heart failure, myocardial infarction, and cardiac arrest. The study aimed to assess independent predictors of POAF and derive and validate a score for risk prediction in clinical practice. This was a retrospective cohort study including all consecutive candidates to all types of noncardiac elective surgery attending a cardiological preoperative assessment from 2016 to 2019. Exclusion criteria were a previous diagnosis of AF and the cancelation of the planned surgery. A total of 2,048 patients were enrolled (1350 men, aged 72 ± 12 years). A total of 44 patients experienced POAF (2.1%) - median 3 days (first to third quartile 2 to 4 days). Age (odds ratio [OR] 1.03 for each year, 95% confidence interval [CI] 1.01 to 1.07), hypertension (OR 3.43, 95% CI 1.22 to 9.63), thyroid dysfunction (OR 2.47, 95% CI 1.22 to 5.01), and intermediate or high-risk surgery (OR 18.28, 95% CI 2.51 to 33.09) resulted as independent predictors of POAF (all p <0.05). The Hypertension, Age, surgery Risk, and Thyroid dysfunction score (OR 2.59 for each point, 95% CI 1.79 to 3.75, p <0.001) was then created based on those 4 items. A cut-off score ≥6 had a 70% sensitivity and a 72% specificity in detecting POAF (area under the curve 0.76). Bootstrapping for internal validation confirmed the overall results (area under the curve 0.72). In conclusion, POAF complicates around 2% of all noncardiac surgery. A 4-item risk score, such as the Hypertension, Age, surgery Risk, and Thyroid dysfunction score, could be effective in implementing POAF screening and improving management.