RESUMO
Atrial fibrillation (AF) is the most common arrhythmia after cardiac surgery with cardiopulmonary bypass (CPB).The value of N-terminal (Nt)-pro brain natriuretic peptide (BNP) in predicting AF complicating cardiac surgery is not well studied. Our objective is to determine its predictive value in the occurrence of AF after cardiac surgery with CPB. In a prospective observational study, including patients scheduled for cardiac surgery with CPB, we collected blood samples for each patient: the first one immediately after the induction of anesthesia and before CPB. The subsequent samples were taken at the end of the CBP (H0), 4 hours later (H4), and every day during the first four days (H24, H48, H72 and H96). Nt-proBNP and cardiac troponin (cTnI) were measured in each sample. The levels of Nt-proBNP were significantly increased in patients who developed AF. The receiver operating characteristic curve (ROC) analysis of Nt-proBNP studied at different times showed that assays at the end of the CPB and at H4 had the maximum area under the curve (AUC). A threshold value of 353.5 pg/mL of Nt-proBNP at the end of the CPB showed a sensitivity of 71% and a specificity of 84% for the prediction of AF and an AUC of 0.711. The threshold value (307.5 pg/mL) of Nt- proBNP measured at H4 had the same sensitivity but a lower specificity (74%) and AUC = 0.709. We conclude that Nt-proBNP values of 353 and 307 pg/mL at 0 and 4 hour after CPB could predict occurrence of AF.