The use of N-terminal pro-brain natriuretic peptide as a predictor of atrial fibrillation after cardiac surgery

Abstract

Aim: Atrial fibrillation (AF) is the most common arrhythmia after cardiac surgery with cardiopulmonary bypass (CPB). The value of Nt-pro BNP in predicting AF complicating cardiac surgery is not well studied. Our objective is to determine its predictive role in the occurrence of this complication after heart surgery with cardiopulmonary bypass.

Methods: It is a prospective observational study including patients proposed for scheduled cardiac surgery with normo-thermal CPB. We performed blood samples for each patient: the first one immediately after the induction of anesthesia and before CPB. The following samples were made 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 cTnI were measured in each sample. The postoperative AF was defined as any episode of AF documented of a period not less than 15 min recorded in the first 3 days post operative.

Results: The most common cardiovascular complication was the AF (17.5%). Rates of Nt-proBNP were significantly increased in patients who developed this complication. The ROC analysis of NT-proBNP at different times studied for the prediction of AF showed that assays at the end of the CPB and those of the 4th postoperative hour (H4) had the best area under the curve (AUC). A threshold value of 353.5 mg/mL of Nt-proBNP at the end of the CPB has a sensitivity of 71% and a specificity of 84% for the prediction of the AF and an AUC of 0.711. The threshold value (307.5 mg/mL) of Nt-proBNP measured at H4 has the same sensitivity but with a lower specificity (74%) and AUC=0.709.

Discussion and conclusion: An early Nt pro BNP at H0 or H4, respectively, and with thresholds of 353 and 307 pg/mL could predict the occurrence of the AF. In this case, a primary prevention could be envisaged.