The usefulness of measuring B-type natriuretic peptide (BNP) levels in the postoperative (PO) period of cardiac surgery (CS) has been frequently assessed.The objective this study is to correlate BNP levels and occurrence of Atrial Fibrillation (AF) in the PO period of CS.
Prospective study with a classic cohort of 77 patients (pts) undergoing CS and consecutively selected between August/2003 and January/2005. Their mean age was 66.9±9.89 years, 22 (28.5%) were females, and the mean Euroscore was 4.26. The BNP level was measured in the preoperative period (BNPPre), and in the first (BNP1) and sixth (BNP6) PO hours. The BNP level was quantitatively measured by use of immunofluorescence (Biosite Triage BNP Test). The occurrence of AF in the PO period was correlated with the following variables: Euroscore; age; sex; preoperative creatinine level and ventricular function; duration of ECC; SOFA on the first PO day; and BNP (Pre, 1, and 6) levels. The statistical analysis comprised the following tests: Student t; Chi-Square; Mann-Whitney followed by ROC curve construction; and principal component analysis.
In the sample studied, 13 pts (16.8%) had AF in the PO period. A significant correlation was observed between the BNP levels [BNPPre (0.01), BNP1 (0.011), and BNP6 (0.03)] and the occurrence of AF. None of the other variables tested correlated with the occurrence of AF. After the principal component analysis, the 3 BNP levels maintained the correlation with the occurrence of AF. BNPPre had a better AUC (ROC) (0.727), in which values greater than 100 pg/dL correlated with the occurrence of AF.
In the population studied, the occurrence of AF showed a correlation with the 3 BNP levels measured, and all of them were independently associated with the outcome. A BNPPre level greater than 100 pg/dL correlated with the occurrence of AF in the PO period of CS.
The BNP showed to be a useful risk marker for the occurence of FA.
Alexandre Felipe, None.