Utility of Brain Natriuretic Peptide as a Predictor of Atrial Fibrillation After Cardiac Operations

Background. Atrial fibrillation (AF) occurs frequently after coronary bypass grafting and valve operations. Brain natriuretic peptide (BNP) has been shown to predict recurrence of AF in congestive heart failure. It is a potential biomarker for preoperative risk stratification for development of AF in at-risk patients. Methods. A total of 398 consecutive patients were prospectively evaluated for new-onset AF after heart operations. Patients with a history of AF and presence of permanent pacemaker were excluded. BNP levels were measured before and immediately after the operation. Results. AF occurred in 20%. AF was more likely to develop in patients who were older, who underwent valve operations, had a lower ejection fraction, and a larger left atrial size. Preoperative exposure to statins (62% vs 43%, p < 0.01) and angiotensin inhibitors (60% vs 45%, p = 0.02) was more common in patients without AF. BNP values were insignificantly higher preoperatively ( 361 vs 302 mg/dL, p = 0.3) and postoperatively ( 312 vs. 229 mg/ dL, p = 0.15) in patients with AF. Multivariate logistic analysis showed that older age ( odds ratio [ OR], 3.1, 95% confidence interval [CI], 1.7 to 5.6), lower ejection fraction ( OR, 2.0; 95% CI, 1.2 to 3.3), larger left atrial size ( OR, 3.1; 95% CI, 1.9 to 4.9), and nonuse of angiotensin inhibitors ( OR, 2.3; 95% CI, 1.1 to 4.8) were independently associated with AF. Conclusions. This study does not support use of BNP for prediction of AF. Age, low ejection fraction, large left atrial size, and nonuse of angiotensin blocking agents were found to be significant predictors of AF development.